JP2010266462A - Method for manufacturing reaction cell for automatic analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reaction cell having excellent reliability, capable of reducing adhesion of bubbles, and preventing mutual contamination of a sample or a reagent between adjacent reaction cells; and to provide a method for manufacturing the reaction cell and an automatic analyzer loaded with the reaction cell. <P>SOLUTION: This automatic analyzer includes a plurality of reaction cells, a means for supplying a sample from an opening part on an upper part of a reaction vessel, a reagent container for accumulating a plurality of kinds of reagents respectively exclusively, a reagent supply means for supplying a prescribed amount of reagent from the reagent container from the opening part on the upper part of the reaction vessel, and a means for measuring a property of the sample in the reaction vessel in the middle of a reaction or in the state where the reaction is finished. In the analyzer, the reaction cell made of a transparent resin, having an inner wall surface comprising a hydrophilic portion and a hydrophobic portion is used. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reaction cell for spectrophotometric analysis used in an automatic analyzer for medical diagnosis such as biochemical analysis reaction and immune reaction, a method for partially modifying the inner wall surface of the reaction cell, and the reaction cell. The present invention relates to an on-board automatic analyzer.

  In clinical tests for medical diagnosis, biochemical analysis and immunological analysis of proteins, sugars, lipids, enzymes, hormones, inorganic ions, disease markers, etc. in biological samples such as blood and urine are performed. In clinical examination, since it is necessary to process a plurality of examination items with high reliability and at high speed, most of the examination items are executed by an automatic analyzer. Conventionally, as an automatic analyzer, for example, a biochemical analyzer that performs biochemical analysis by measuring the absorbance of a reaction solution obtained by mixing a desired reagent with a sample such as serum and reacting it is known. It has been. This type of biochemical analyzer includes a container for storing a sample and a reagent, a reaction cell for injecting the sample and the reagent, a mechanism for automatically injecting the sample and the reagent into the reaction cell, and mixing the sample and the reagent in the reaction cell. Automatic stirring mechanism, a mechanism for measuring the spectral spectrum of the sample during or after the reaction, and an automatic cleaning mechanism for sucking and discharging the reaction solution after the spectral spectrum measurement is completed and washing the reaction cell. (For example, Patent Document 1).

  In the field of automatic analyzers, miniaturization of samples and reagents has become a major technical issue. In other words, with the increase in the number of analysis items, the amount of sample that can be divided into single items has decreased, and the sample itself may be valuable and cannot be prepared in large quantities. It has come to be done routinely. In addition, as the analysis content becomes more sophisticated, reagents are generally more expensive, and there is a demand for reducing the amount of reagents in terms of cost. Such a small amount of sample and reagent is also a strong motivation for further miniaturization of the reaction cell. In addition, miniaturization of the reaction cell and a reduction in the amount of necessary samples and reagents have advantages that lead to improvement in analysis throughput and low waste liquid.

  Here, a reaction cell (also called a reaction vessel) used for a general automatic analyzer is generally formed of glass or synthetic resin. For example, according to Patent Document 2, the material of the reaction cell is selected from resin materials having low water absorption, low moisture permeability, high total light transmittance, low refractive index, and low molding shrinkage. Specifically, one type selected from polycycloolefin, polycarbonate resin, acrylic resin, and polystyrene resin is preferably exemplified. In addition, Patent Document 4 discloses a problem relating to a synthetic resin reaction cell, in which an initial detection failure in which a bubble generated when a biological sample and a reagent flow into the cell adhere to the inner wall of the cell and measurement cannot be performed is reduced. Cite. At this time, the cause of bubble adhesion is that the wettability of the cell inner wall surface is low.

  Effective synthetic resin (also called plastic or polymer resin) surface wettability, that is, effective means for hydrophilizing the surface include oxygen plasma treatment, ozone treatment, ozone water treatment, corona discharge treatment, and UV treatment. Etc. are known. According to Non-Patent Document 1, surface modification by forming a graft polymer after introducing peroxide on the surface by oxidizing the polyethylene surface, which is a kind of polymer resin, by corona discharge treatment. Is possible. Patent Document 3 reports oxidation and hydrophilization of a plastic container by ozone treatment.

Japanese Patent No. 1706358 JP 2005-30763 A JP 2000-346765 A

Journal of Polymer Science: Part A: Polymer Chemistry, Vol.26, 3309-3322.

  In the field of automatic analyzers, the amount of samples and reagents is becoming increasingly smaller, and the demand for miniaturization of the apparatus is increasing. For this reason, the following two problems have emerged as new problems that have not been regarded as problems. The size of the reaction cell used in the past was sufficiently large compared to bubbles, so even if the bubbles hit the optical axis, the absorbance hardly fluctuated within the practical range, and it was extremely rare to have trouble. It has been found that the influence of bubbles becomes obvious in experiments for reducing the reaction cell volume. The cause of this problem is the hydrophobicity of the transparent resin used for the reaction cell material. Therefore, when the inner wall surface of the reaction cell was hydrophilized, it was confirmed that bubble adhesion did not occur.

  However, the second problem emerged when the hydrophilic treatment of the reaction cell was fully performed. When the inner wall of the reaction cell is hydrophilized from the bottom to the top opening, the test solution rises to the edge of the reaction cell by capillary action, and cross-contamination that mixes with the reagent of the adjacent reaction cell easily occurs.

  In addition, although the phenomenon is similar to the above, reaction cells that have been used once are used in sequence after cleaning, but the components of the reaction solution remaining on the inner surface of the reaction cell are mixed in the next analysis, which adversely affects measurement data. There is a case. This phenomenon is called cross contamination. Some of the reaction liquid components that may remain on the inner surface of the reaction cell include hydrophilic substances such as proteins and inorganic ions in addition to lipids.

  Miniaturization of reaction cells tends to promote cross-contamination and is expected to become a bigger problem in the future. In order to cope with the constant trend of miniaturization of automatic analyzers and a small amount of samples and reagents, it is necessary to solve the above two problems. The present invention aims to meet these needs.

  In order to solve these problems, it is necessary to hydrophilize the inner wall of the reaction cell, but the hydrophilized region must be limited to the height required for spectroscopic analysis from the bottom of the reaction cell. Effective means for hydrophilizing the organic resin surface include candidates such as oxygen plasma treatment, ozone treatment, ozone water treatment, corona discharge treatment, and UV treatment. However, these are all suitable for the purpose of processing an object having a planar shape, and are simple enough to achieve the purpose in a single step with respect to the surface of a special three-dimensional structure (see FIG. 1) handled by this patent. In general, it is difficult to find a method. In addition, it is not easy to process by limiting the area. For example, Patent Document 5 describes the oxidation and hydrophilization of a plastic container by ozone treatment. However, in this method, the plastic container cannot be partially oxidized and the plastic container is partially limited. It cannot be hydrophilized.

  Thus, the inventors have come up with an application of the corona discharge method in which an organic resin plate is sandwiched between two electrode plates for discharge treatment. In this method, corona discharge is generated between an external electrode surrounding a reaction cell block made of an organic resin from the outside and a rod-shaped internal electrode inserted into each unit cell (see FIG. 4). At this time, since the external electrode surfaces are close to the outer front and back of the spectrophotometric surface of the cell, discharge is performed between the opposing rod electrodes, and both inner walls of the spectrophotometric surface are subjected to corona discharge treatment. In addition, by installing external electrodes on the gaps and the bottom surface of the unit cell, the corona discharge treatment can also be performed on the non-photometric surface and the bottom surface. This time, the photometric surface of the reaction cell was subjected to corona discharge treatment.

  Since the corona discharge treatment is performed in an atmosphere containing oxygen such as air, oxygen atoms are introduced into the surface of the organic resin. Oxygen atoms are introduced into the surface of the organic resin in the form of hydroxyl groups, ether groups, carbonyl groups, carboxyl groups, and since these are all hydrophilic functional groups, the hydrophilicity of the original highly hydrophobic organic resin surface Will improve. The hydrophilicity of the resin surface is measured by a decrease in the contact angle of water, but it was found that the inner wall of the cell block subjected to corona discharge by the above method has a decreased contact angle and improved hydrophilicity. Moreover, the introduction state of oxygen atoms could be confirmed from the measurement result of XPS (X-ray photoelectron spectrum).

  In addition, since the discharge occurs only in a region where the inner and outer electrodes face each other, there is a possibility that the processing area can be limited. In fact, it was confirmed that the hydrophilized region can be limited only to the region where the electrodes face each other, that is, the region where corona discharge occurs. That is, only the inner wall surface from the bottom of the reaction cell made of a transparent organic resin to a predetermined height can be subjected to a hydrophilic treatment by corona discharge.

  The hydrophilicity of the surface subjected to the corona discharge treatment is based on the hydroxyl group, ether group, carbonyl group, or carboxyl group introduced by the treatment. ) Also produced. This suggests the possibility of vinyl polymerization starting from the peroxide on the surface, that is, graft polymerization. Here, the graft polymerization refers to an active molecular structure that becomes a polymerization starting point by using some means with respect to the already existing first polymer, and the monomer is polymerized using this as a starting point. This is a technique for bonding a second polymer having another property. Therefore, when the surface of the reaction cell subjected to corona discharge for a relatively long time was thermally reacted with various hydrophilic vinyl monomers under deoxidation, vinyl polymerization progressed on the cell surface, and surface hydrophilization was achieved. I confirmed that I can do it.

  A surface obtained by graft polymerization of a hydrophilic vinyl monomer is higher in stability than a surface having only corona discharge. For example, the hydrophilicity of the surface of the reaction cell only subjected to the corona discharge treatment is deteriorated and not restored by being left at a high temperature when the corona discharge treatment is performed for a short time. On the other hand, even if the hydrophilicity of the reaction cell surface subjected to corona discharge treatment for an appropriate long time or the reaction cell surface to which graft polymerization is added after corona discharge is deteriorated once by high temperature treatment, it is restored by immersion in water. The cell subjected to corona discharge treatment or graft polymerization treatment has no change in appearance, transparency in the wavelength range of 300 nm to 800 nm necessary for spectroscopic analysis is sufficient, and optical properties are not adversely affected.

  As described above, according to the present invention, a stable hydrophilic treatment can be performed on the inner wall of the reaction cell for an automatic analyzer with a limited area. It can solve the problem of cross-contamination between cells without causing it, and can provide an automatic analyzer that realizes a highly reliable clinical chemistry test.

  According to the present invention, the cell inner wall can be subjected to a hydrophilic treatment only in the region close to the cell closing portion of the spectrophotometric surface that does not like bubble adsorption, and the region closer to the opening than that of the cell inner wall is made hydrophobic. Can be held as is. For this reason, the change in spectral transmittance due to bubble adsorption does not occur, and the accuracy of measurement data is improved. In addition, the hydrophobicity of the cell opening region prevents wetting of the reagent and sample, thereby preventing cross-contamination of samples between reaction cells and improving data reliability. These effects contribute to the miniaturization of samples and reagents, and also contribute to reducing the running cost of the automatic analyzer.

The perspective external view of a cell block. The perspective external view of a division cell. The perspective external view of a division cell. The schematic diagram of corona discharge local treatment. The perspective external view of the division | segmentation cell after a corona discharge local process. The figure which shows a contact angle measurement result. The figure which shows the result of XPS. The figure which shows the result of XPS. The process flowchart of a graft polymerization process. The cross-sectional schematic diagram of a photometric surface inner wall part. The figure which shows the structural example of an automatic analyzer. The figure which shows the result of XPS, and a bubble adhesion rate. The schematic diagram of the photometric surface of a cell. The perspective external view of a division cell. The schematic diagram of corona discharge local treatment. The schematic diagram of a spectrophotometer. The schematic diagram of a spectrophotometer.

EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.
Example 1 Local Hydrophilization by Corona Discharge Treatment—Part 1
A reaction cell for an automatic analyzer (hereinafter referred to as “cell”) was manufactured by injection molding using polycycloolefin as a raw material. Incidentally, the cell material may be one selected from polycycloolefin, polycarbonate resin, acrylic resin, and polystyrene resin. It is desirable to select a polycycloolefin from the viewpoint of low water absorption, low moisture permeability, high total light transmittance, low refractive index, and low mold shrinkage.

  In this embodiment, a cell block formed by integrally molding four single cells was used. FIG. 1 shows a perspective external view of a cell block. The molded cell block 50 includes four single cells 51. The long side 101 of the cell block 50 is 60 mm, the short side 102 is 10 mm, and the height 103 is 40 mm. When the single cell 51 is mounted on the automatic analyzer, the reaction progress and the reaction result of the sample and the reagent are measured by the spectrum. Each single cell has two surfaces (photometry surfaces) through which measurement light passes and non-photometry surfaces through which measurement light does not pass. FIG. 2 is a cross-sectional view of a single cell divided into two along the long axis of the non-photometric surface. The single cell 51 includes a non-photometric surface outer wall portion 111, a non-photometric surface inner wall portion 112, a photometric surface outer wall portion 113, a photometric surface inner wall portion 114, and a bottom surface 115. The details are shown in FIG. The dimension of the inner wall portion of the single cell is such that the half length 116 of the non-photometric surface is 3 mm, the length 117 of the photometric surface is 4 mm, the height 118 is 30 mm, the single cell thickness 150 is 1 mm, An opening 140 is provided.

  All the single cells 51 were injected with 600 μl of ethanol and allowed to stand for 24 hours. After removing the ethanol, it was placed in a vacuum desiccator and dried to clean the inner surface of the single cell. Next, corona discharge local treatment was performed. FIG. 4 shows a schematic diagram of the corona discharge local treatment. The photometric surfaces of the four single cells 51 of the cleaned and dried cell block 50 were sandwiched between the cathode plates 218. The cathode plate is connected to the ground 217 via the wiring 216. By adjusting the size of the cathode plate, the height of the corona discharge treatment surface of the cell inner wall can be limited. In this embodiment, the insertion depth was determined such that the inner wall from the bottom surface of each single cell to 14 mm was processed. Thereafter, a corona discharge anode rod electrode 214 was placed in each single cell 51 toward the center of the bottom surface of each single cell up to a height of 1 mm from the bottom surface. The corona discharge anode electrode 214 has a diameter of 2 mm and a length of 50 mm. The corona discharge anode electrode 214 is connected to the corona discharge source 211 via the anode 213 and the wiring 212. As the corona discharge power source, polydyne manufactured by Navitas was used. Next, corona discharge treatment was performed to the height of the inner wall of the single cell corresponding to the height in contact with the cathode plate by applying a voltage of 8.5 kV in the atmosphere.

At this time, if a cathode plate is provided on the bottom outer wall of the reaction cell or the outer wall of the non-photometric surface, corona discharge treatment can be performed on the bottom surface or non-photometric surface of the reaction cell. That is, the corona discharge treatment position can be limited by the position where the cathode plate is installed. As shown in FIG. 13, the area of the metering surface 41 of the conventional cell and S _5, if the area of the metering surface 42 of the miniaturized cell was S _6, S ₆ is smaller than S _5. The area of the photometric surface of the cell can be reduced to the area S ₄ of the photometric area 40. Therefore, when the area S ₆ becomes substantially equal to S ₄ as the cell size is reduced, not only the photometric surface but also the non-photometric surface and the bottom surface are made hydrophilic so that light passes through the photometric region 40 and the solution is detected. At this time, no bubbles are attached to the light transmitting region, and stable measurement can be performed.

  FIG. 14 shows a cross-sectional perspective view of an example of a single cell in which the photometric surface, the non-photometric surface, and the bottom surface are made hydrophilic by corona discharge treatment. The corona discharge treatment was performed on the region 160 including the bottom surface 115 to the boundary line 161 of the photometric surface inner wall portion 114 of the cell and the bottom surface 115 to the boundary line 162 and the bottom surface 115 of the non-photometric surface inner wall portion 112. At this time, with the boundary lines 161 and 162 as the boundary, the closed portion 130 side became hydrophilic and the opening portion side became hydrophobic, and there was a clear difference in hydrophilicity. At this time, the corona discharge local treatment was similarly applied to the inner wall portion of the facing surface of the photometric surface and the inner wall portion of the facing surface of the non-photometric surface shown in the figure. Similar corona discharge local treatment could be performed simultaneously on all of the plurality of single cells provided in the cell block. By changing the position of the cathode plate, the portion to be subjected to the corona discharge treatment can be limited. Moreover, it is also possible to process a part limitedly by carrying out a corona discharge process after previously covering the part which does not want to perform a corona discharge process with the same material as a reaction cell.

  In FIG. 5, the cross-sectional perspective external view of the other example of the single cell after a corona discharge local process is shown. Corona discharge treatment was performed on a portion 120 from the bottom surface 115 to the boundary line 119 in the photometric surface inner wall portion 114 of the cell 51. At this time, with the boundary line 119 as a boundary, the closed portion 130 side became hydrophilic and the opening portion side became hydrophobic, and there was a clear difference in hydrophilicity. At this time, the corona discharge local treatment was similarly applied to the inner wall portion of the surface opposite to the photometric surface shown in the figure. Similar corona discharge local treatment could be performed simultaneously on all of the plurality of single cells provided in the cell block. At this time, the corona discharge treatment can be performed not only on the photometric surface but also on the non-photometric surface and the bottom surface by installing the cathode plate on the non-photometric surface and the bottom surface. In Examples 1 to 7, an example in which a cell in which only a photometric surface is subjected to corona discharge treatment is prepared is shown. It should be noted that detection bubbles can be eliminated if bubbles do not adhere to a region (photometry unit) through which light is transmitted when measuring a spectral spectrum.

  When the contact angle with water on the photometric surface of the cell was measured before and after the corona discharge treatment for 1 second, the contact angle when the corona discharge treatment was not performed was 90 degrees and after the corona discharge treatment for 1 second. The contact angle was 51 degrees.

  For measurement of the contact angle, Drop Master 500 manufactured by Kyowa Interface Science was used. Using a syringe, 1 μl of pure water was dropped onto the treated cell surface, and the static contact angle 0.5 seconds after the landing was measured by the θ / 2 method. For the measurement, two treated samples were prepared, measured at six different points on the treated surface, and the average value was obtained. As a result, the contact angle with water on the cell surface (treatment time 0 second) before corona discharge treatment was 90 degrees, whereas the contact angle with water was reduced to 51 degrees by corona discharge treatment. . Further, the contact angle of the portion not subjected to the corona discharge treatment was 90 degrees, which was the same as that of the cell surface not subjected to corona discharge treatment. Thus, it was confirmed that the corona discharge treatment can be selectively performed. That is, hydrophilicity can be imparted by limiting the area on the cell surface by corona discharge treatment.

  Next, the transition of the contact angle with water after leaving the cell subjected to the corona discharge treatment for 1 second at room temperature, and the presence or absence of bubbles when 150 μl of water was injected into the cell were examined. FIG. 6 shows the contact angle of the cell surface with water over time. The elapsed time (days) is shown on the horizontal axis, and the contact angle (degrees) is shown on the vertical axis. Since the contact angle of the cell that has been subjected to the corona discharge treatment for 1 second increased as the number of days elapses, the hydrophilicity decreases with time. Table 1 shows the presence or absence of bubble adhesion over time.

  When 150 μl of water was injected into the cell after the lapse of 0 days and 7 days, no bubbles adhered. However, after 14 days, 21 days, and 28 days, when 150 μl of water was injected into the cells, bubbles adhered. Therefore, the hydrophilization by the corona discharge treatment for 1 second is effective for maintaining the hydrophilicity for a short time of about 7 days.

  The reaction cell of this example was confirmed as a reaction cell for an autoanalyzer, which does not cause bubble adhesion, has stirring stability and transparency, and can prevent cross-contamination of samples and reagents between the cells. .

  Further, the corona discharge treatment shown in FIG. 4 can be applied to other shapes of cell blocks. As shown in FIG. 15, in the cell block 60 in which a plurality of cells 61 share the photometric surface 62, the outer wall of the region to be hydrophilized on the photometric surface is sandwiched between cathode plates 218, so that the height of the corona discharge treatment surface of the cell inner wall is increased. The corona treatment can be performed by limiting the thickness. By making the photometric surface hydrophilic, it is possible to carry out stable measurement without bubbles adhering when light is transmitted through the photometric region and a solution is detected.

Example 2 Local Hydrophilization by Corona Discharge Treatment-Part 2-
A reaction cell for a biochemical automatic analyzer composed of the same polycycloolefin as in Example 1 was prepared. Here, the treatment time was extended to 10 seconds under the same conditions as in Example 1, and the corona discharge local treatment was performed to locally hydrophilize the portion from the bottom of the photometric surface inner wall of the cell to the desired height.

  As a result, as in Example 1, the contact angle with water on the cell surface not subjected to corona discharge treatment (treatment time 0 minutes) was 90 degrees, whereas the water on the cell surface subjected to corona discharge treatment for 10 seconds The contact angle was 41 degrees. Thus, the contact angle with water fell by processing by corona discharge. That is, hydrophilicity can be imparted to the cell surface by corona discharge treatment. When the corona discharge treatment time is 1 second, the contact angle with water is about 51 degrees, and when the corona discharge treatment time is 10 seconds, the contact angle with water is about 41 degrees. By increasing the length to 10 seconds, the hydrophilicity can be further increased. Also, if the corona discharge treatment time was extended to 20 seconds, the cell surface was deformed and discolored, making it difficult to use it in an automatic analyzer. Therefore, the upper limit of the corona discharge treatment time was set to 10 seconds here. .

  Next, Table 2 summarizes the results of elemental analysis of the corona discharge-treated surface by XPS (X-ray photoelectron spectroscopy). Here, the relative abundance ratio of carbon, oxygen, and nitrogen with respect to the corona discharge treatment time is shown. The X-ray photoelectron spectroscopy (XPS) device made by SHIMADZU-CRATOS is used for the measurement. In order to compare the relative abundance ratio of carbon, oxygen and nitrogen, wide scan with Pass Energy of 20 eV in the range of 1400 eV to -20 eV. I did it.

  As shown in Table 2, the relative abundance of oxygen was below the lower limit of detection on the corona discharge treatment time of 0 seconds, that is, on the untreated cell surface. On the other hand, the relative oxygen abundance of the cell surface that was subjected to corona discharge treatment for 1 second was 7.9%. Oxygen is introduced by corona discharge treatment, and the polycycloolefin is oxidized and hydrophilized. And the relative oxygen abundance of the cell surface subjected to the corona discharge treatment time of 10 seconds is 15.9%, and more oxygen is introduced than the cell subjected to the corona discharge treatment time of 1 second, and it is more strongly oxidized and hydrophilized. Has been. From the viewpoint of reducing the contact angle and from the viewpoint of the relative oxygen abundance of XPS, the corona discharge treatment time of 10 seconds is more advantageous in terms of improving the hydrophilicity of the cell surface than 1 second.

  Next, in the same manner as in Example 1, the presence or absence of bubbles was examined when 150 μl of pure water was poured into a cell subjected to corona discharge treatment. In order to evaluate the change in hydrophilicity in an accelerated manner, the cells subjected to each treatment were heat-treated for 240 hours in a thermostatic bath maintained at 75 ° C.

  As a result, the cell subjected to the corona discharge treatment time of 1 second had a contact angle with water on the cell surface of 51 degrees in the state immediately after that (elapsed time, 0 hour), and no bubbles were attached. After 240 hours of heat treatment in a thermostat kept at ° C., the contact angle of the cell surface with water increased to 73 degrees and bubble adhesion occurred. On the other hand, the cell subjected to the corona discharge treatment time of 10 seconds had a contact angle on the cell surface of 41 degrees and no bubbles attached in the state immediately after that (elapsed time, 0 hour), but stored in a thermostatic chamber at 75 ° C. After 240 hours, the contact angle of the cell surface with water increased to 68 degrees. However, bubble adhesion did not occur in this cell. Therefore, it was confirmed that a stable hydrophilization treatment was possible by applying a corona discharge treatment to a part of the cell inner wall for 10 seconds. Further, the contact angle of the portion not subjected to the corona discharge treatment remained 90 degrees, which was the same as that of the cell surface not subjected to the corona discharge treatment. That is, the inner wall of the reaction cell could be selectively subjected to corona discharge treatment, and a reaction cell having a stable hydrophilic portion and hydrophobic portion on the inner wall portion could be produced.

  Moreover, the XPS measurement of the cell surface which gave corona discharge by each processing time was performed, and the cell surface was analyzed in detail. In order to compare the bonding state of carbon, narrow scan of C1s was performed in the range of 271 eV to 311 eV with Pass Energy of 2 eV.

  FIG. 7 shows the C1s narrow scan result of the cell surface after the corona discharge was treated for 1 second. The obtained narrow scan peak was separated and analyzed (deconvolved) into each binding state. The range delimited by the arrows 310 is a range in which CC and CH bond peaks are detected. Similarly, the range of the arrow 311 is a C—O (ether, alcohol) bond, the range of the arrow 312 is a C═O (carbonyl) bond, the range of the arrow 313 is an O═C—O (carboxyl) bond, and the arrow 314 is The range is a range where O = C—O—O (peroxide) is detected. As shown in FIG. 7, all of the oxides (C—O, C═O, O═C—O, O═C—O—O) are present on the cell surface that has been subjected to corona discharge for 1 second. Is generated.

  FIG. 8 shows the C1s narrow scan result of the cell surface after the corona discharge was treated for 10 seconds. The range delimited by the arrow 320 is a range in which the C—C and C—H bond peaks are detected. Similarly, the range of the arrow 321 is a C—O (ether, alcohol) bond, the range of the arrow 322 is a C═O (carbonyl) bond, the range of the arrow 323 is an O═C—O (carboxyl) bond, and the arrow 324 The range is a range where O = C—O—O (peroxide) is detected. As shown in FIG. 8, all of the above oxides (C—O, C═O, O═C—O, O═C—O—O) are present on the cell surface that has been subjected to corona discharge for 10 seconds. Is generated. However, the abundance ratio of individual bonds varies depending on the corona discharge treatment time.

  The ratio of the carbon bonding state on the cell surface subjected to each corona discharge treatment time (0 second, 1 second, 10 seconds) was as follows. Only 100% of C—C bonds and C—H bonds were present in the corona discharge treatment for 0 second, that is, on the untreated cell surface. On the other hand, on the cell surface after 1 second of corona discharge treatment, there are 68.6% C—C bond and C—H bond, 6.4% C—O bond, 10.7% C═O bond, O = C—O bond was 11.5%, and O═C—O—O bond was 2.8%. Further, 69.4% of C—C bond and C—H bond exist on the cell surface after 10 seconds of corona discharge treatment, 11.2% of C—O bond, 7.1% of C═O bond, O = C—O bond was present at 5.3%, and O═C—O—O bond was present at 7.0%. On the cell surface after 10 seconds of corona discharge treatment, the proportion of CO bonds containing alcohol groups having high hydrophilicity is particularly high at 11.2%, and the proportion of CO bonds on the surface of corona discharge treatment 1 second cells is 6%. It was higher than 4%. This is the reason why the corona discharge treatment time is increased from 1 second to 10 seconds, so that hydrophilicity is maintained even after heating at 75 ° C. for 240 hours, and no bubble adhesion occurs.

  In addition, 600 μl of pure water was once put in a cell that had been allowed to pass at 75 ° C. for 240 hours, and immersed at room temperature (this operation was named “water immersion”), and then the contact angle on the cell surface was measured. The contact angle of the untreated cell surface was 90 °, the contact angle of the cell surface treated with corona discharge for 10 seconds was 41 °, 68 ° after 240 hours at 75 ° C., and 56 ° after water immersion. Once the hydrophilicity of the cell surface, the hydrophilicity of which was reduced by high-temperature heating, was recovered by immersion in water. Even after the heat treatment, the hydrophilicity was comparable to that after the corona discharge treatment. Subsequently, the stability of the cell surface treated with corona discharge for 10 seconds before and after heating at 75 ° C. for 240 hours was analyzed by XPS measurement. As described in Table 2, the oxygen content of the surface after the production of the cell treated with corona discharge for 10 seconds was 15.9%. The oxygen content of the surface after heating the cell treated with corona discharge for 10 seconds at 75 ° C. for 240 hours was 7.8%. It was found that although there was a decrease in oxygen by about 40% due to heating, sufficient hydrophilicity was maintained.

  The cell treated with corona discharge for 10 seconds showed the same hydrophilicity after the heat treatment as before the heat treatment. Therefore, it was found that the extension of the discharge time is effective for stabilizing the hydrophilicity. Therefore, an experiment was carried out to shorten the discharge time to 7 seconds and 4 seconds, aiming at stable hydrophilicization of the cell surface and efficiency of the corona discharge treatment. A reaction cell for a biochemical automatic analyzer made of polycycloolefin was prepared in the same manner as in Example 1. Here, the corona discharge local treatment was performed under the same discharge conditions as in Example 1 with a treatment time of 7 seconds and 4 seconds, and the portion from the bottom surface of the photometric surface inner wall portion of the cell to the desired height was locally hydrophilized. Table 3 shows the change in the contact angle with water with respect to the treatment time together with the results of the discharge time of 0 seconds, 1 second, and 10 seconds.

  The contact angle of the untreated cell surface was 90 degrees, whereas the contact angle was lowered by corona discharge treatment. That is, hydrophilicity can be imparted to the cell surface by corona discharge treatment. The contact angle that was about 51 degrees in the corona discharge treatment time of 1 second was about 41 degrees in the treatment time of 4 seconds and about 39 degrees in the treatment time of 7 seconds. Therefore, by increasing the corona discharge treatment time, More hydrophilicity can be increased.

  Next, Table 4 summarizes the results of elemental analysis of the corona discharge treated surface by XPS (X-ray photoelectron spectroscopy). Here, the oxygen relative abundance ratio with respect to the corona discharge treatment time is shown. For the measurement, a SHIMADZU-CRATOS X-ray photoelectron spectroscopy (XPS) apparatus was used, and in order to compare the relative oxygen abundance ratio, a wide scan was performed in the range of 1400 eV to -20 eV, with Pass Energy of 20 eV.

  As shown in Table 4, the relative abundance of oxygen was below the lower limit of detection on the corona discharge treatment time of 0 seconds, that is, on the untreated cell surface. On the other hand, the relative oxygen abundance of the cell surface that was subjected to corona discharge treatment for 1 second was 7.9%. Oxygen is introduced by corona discharge treatment, and the polycycloolefin is oxidized and hydrophilized. The relative oxygen abundance on the cell surface with a treatment time of 4 seconds was 11.3%, the oxygen relative abundance on the cell surface with a treatment time of 7 seconds was 11.5%, and a corona discharge treatment time of 1 second was applied. Oxygen is introduced more than the above cells and is more oxidized and hydrophilic. From the viewpoint of reducing the contact angle shown in Table 3 and from the viewpoint of the relative oxygen abundance of XPS shown in Table 4, it is advantageous to increase the hydrophilicity of the cell surface by extending the corona discharge treatment time from 1 second. It is.

  Next, the presence or absence of bubbles was examined when 150 μl of pure water was poured into the cell subjected to the corona discharge treatment. In order to evaluate the change in hydrophilicity in an accelerated manner, the cells subjected to the corona discharge treatment for each time were heat-treated in a thermostatic bath at 75 ° C. for 240 hours. The contact angle of the cell surface treated for 4 seconds with corona discharge was 41 degrees before the heat treatment (treatment time 0). After the cell was heat-treated in a thermostatic chamber at 75 ° C. for 240 hours, its contact angle increased to 62 degrees, but no bubbles adhered. In addition, the contact angle with the water on the cell surface subjected to corona discharge treatment for 7 seconds was 39 degrees before the heat treatment (treatment time 0) and increased to 57 degrees after the heat treatment at 75 ° C. for 240 hours, but the bubbles adhered. Did not happen. Therefore, it was confirmed that a stable hydrophilization treatment was possible by applying a corona discharge treatment to a part of the cell inner wall for 4 seconds or 7 seconds. Further, the contact angle of the portion not subjected to the corona discharge treatment remained 90 degrees, which was the same as that of the cell surface not subjected to the corona discharge treatment. That is, the inner wall of the reaction cell could be selectively subjected to corona discharge treatment, and a reaction cell having a stable hydrophilic portion and hydrophobic portion on the inner wall portion could be produced.

  Table 5 summarizes the contact angle with water on the cell surface subjected to corona discharge in each treatment time and the presence or absence of bubble adhesion over time.

  From the results of Table 5, the contact angle of the cells subjected to the corona discharge treatment after the heat treatment decreased most when the discharge time was 7 seconds, and then decreased in the order of 4 seconds, 10 seconds and 1 second. Moreover, the XPS measurement of the cell surface which performed the corona discharge process according to each time was performed, and the cell surface was analyzed in detail. In order to compare the bonding state of carbon, narrow scan of C1s was performed in the range of 271 eV to 311 eV with Pass Energy of 2 eV. Narrow scan peaks were separated and analyzed (deconvolved) into each binding state from the C1s narrow scan results on the cell surface.

  On the cell surface for 4 seconds after corona discharge treatment, 65.4% of C—C bonds and C—H bonds exist, 21.1% of C—O bonds, 4.9% of C═O bonds, and O═ 4.1% of C—O bonds and 4.5% of O═C—O—O bonds were present. In addition, 57.1% of C—C bonds and C—H bonds are present on the cell surface after 7 seconds of corona discharge treatment, 29.9% of C—O bonds, 4.3% of C═O bonds, There were 2.9% O = C—O bonds and 5.8% O═C—O—O bonds.

  Table 6 summarizes the existence ratio of the carbon bonding state on the cell surface subjected to each corona discharge treatment time.

  In particular, the cell surface after 4 seconds of corona discharge treatment contains 21.1% of the C—O bond containing an alcohol group having high hydrophilicity. The ratio was about 15% higher than 6.4%. Further, the ratio of C—O bonds containing alcohol groups having high hydrophilicity is particularly high at 29.9% on the cell surface after 7 seconds of corona discharge treatment, and the ratio of C—O bonds on the surface of the corona discharge treatment 1 second cell. It was about 23% higher than 6.4%. This is because the corona discharge treatment time is increased from 1 second to 4 seconds to 7 seconds, so that hydrophilicity is maintained even after heat treatment at 75 ° C. for 240 hours, and bubble adhesion does not occur. is there.

  The experimental conditions for obtaining the XPS measurement results described in Table 2, Table 4 and Table 6 described above were performed with the detection angle of the XPS detector fixed at 90 degrees. When performing XPS analysis of the resin surface, when the detection angle is fixed at 90 degrees, the information on the resin surface obtained is about 6 nm deep from the outermost surface. Therefore, in order to investigate in detail the difference in hydrophilicity due to the length of the discharge time and heat treatment, the surface composition analysis from the outermost surface to about 5 nm and about 3 nm by changing the XPS detection angle to 60 degrees and 30 degrees, respectively. I did it. Of the cells subjected to the corona discharge treatment, a cell having a discharge time of 1 second having the highest contact angle after the heat treatment and a cell having a discharge time of 7 seconds having the lowest contact angle after the heat treatment are compared.

  Table 7 shows, for each detection angle, the introduction rate (%) of the C—O bond containing a highly hydrophilic alcohol group to the surface obtained from the narrow scan result of C1s of XPS measurement. The C—O bond introduction ratio (%) to the surface here is the C—O bond ratio (%) / [C—O bond ratio (%) + C = O bond ratio obtained from the narrow scan result of C1s. (%) + O = C—O bond ratio (%) + O = C—O—O bond ratio (%)] and oxygen relative abundance.

  As a result, in the cell having a corona discharge treatment time of 1 second, the CO bond introduction ratio, which was 5.7% before the heat treatment, decreased to 1.1% after the heat treatment when the detection angle was 30 degrees. In the same cell, when the detection angle was 60 degrees, the CO bond introduction ratio, which was 4.4% before the heat treatment, decreased to 3.2% after the heat treatment. On the other hand, when the detection angle was 90 degrees, the C—O bond introduction rate, which was 1.6% before the heat treatment, increased to 3.6% after the heat treatment. From this, the C—O bond introduction rate was highest at a detection angle of 30 degrees, ie, about 3 nm from the outermost surface before the heat treatment, but after the heat treatment, the C—O bond introduction rate was highest at a detection angle of 90 degrees, ie, about 6 nm from the outermost surface. The bond introduction rate was high. Therefore, it was found that in the cell having a corona discharge of 1 second, the highly hydrophilic C—O bond, which was present in the 3 nm range from the outermost surface before the heat treatment, moved in the deep direction in the 6 nm range from the outermost surface. This was found to be the cause of the decrease in hydrophilicity and the occurrence of bubble adhesion due to heat treatment.

  On the other hand, in the cell having a corona discharge treatment time of 7 seconds, when the detection angle was 30 degrees, the CO bond introduction rate, which was 5.0% before the heat treatment, was 5.6% after the heat treatment and did not decrease. In the same cell, when the detection angle was 60 degrees, the CO bond introduction rate, which was 6.7% before the heat treatment, was 6.2% after the heat treatment, which was almost unchanged. Further, when the detection angle was 90 degrees, the CO bond introduction ratio, which was 6.4% before the heat treatment, was 5.7% after the heat treatment, which was almost unchanged. From this, it was found that in the cell of the corona discharge treatment 7 seconds, there was almost no change in the CO bond introduction rate accompanying the heat treatment. This is the reason why a cell having a corona discharge treatment time of 7 seconds can retain hydrophilicity for a long time.

  As described above, the corona discharge time is highly related to the relative abundance of oxygen on the cell surface, the C—O bond introduction rate, and bubble adhesion. Therefore, the above results are collectively shown in FIG. The horizontal axis in FIG. 12 is the corona discharge time (seconds), and the oxygen relative abundance (%) 511 and the C—O bond introduction rate (%) 512 are indicated by the first axis introduction rate (%). Further, the bubble adhesion rate (%) 513 in the figure is indicated by the bubble adhesion rate (%) of the second axis. The bubble adhesion rate is a ratio of cells in which bubble adhesion occurs with respect to 100 cell evaluations after the heat treatment. As the discharge time increases, the relative oxygen abundance increases monotonously. As the relative oxygen abundance increased, the bubble adhesion rate decreased, and was 70% at a discharge time of 1 second, and 0% at a discharge time of 4 seconds, 7 seconds, and 10 seconds. On the other hand, the C—O bond introduction rate reached 2.0% at a discharge time of 1 second, 4.2% at a time of 4 seconds, 6.4% at a time of 7 seconds, and then 4. It was 5%. C—O bonds are sufficiently introduced to the cell surface at a discharge time of about 7 seconds, and are discharged for a longer time so that a highly oxidized C═O bond system (C═O bond, O═C—O bond, This is because it was converted to (O = C—O—O bond). The C═O bond system has light absorption around 340 nm. What is required of a reaction cell for an automatic analyzer is a high light transmittance in the range of 300 nm to 800 nm. Therefore, it is desirable to suppress the formation of bonds including C═O bonds. As a result, a reaction cell formed by a treatment with a corona discharge time of 7 seconds is preferred from the viewpoints of both light transmittance and hydrophilic long-term retention.

  The reaction cell of this example was confirmed as a reaction cell for an autoanalyzer, which does not cause bubble adhesion, has stirring stability and transparency, and can prevent cross-contamination of samples and reagents between the cells. .

<Example 3> Local hydrophilization by graft polymerization of acrylamide Here, an example of local hydrophilization of the cell surface by graft polymerization of acrylamide is shown. A reaction cell for an automatic analyzer made of the same polycycloolefin as in Example 1 was prepared. Here, a partial corona discharge treatment was performed under the same conditions as in Example 1 to locally hydrophilize the portion from the bottom surface of the photometric surface inner wall of the cell to the desired height. Since there are many peroxides such as O = C-O-O on the cell surface, it was thought that this could be used as an initiator and graft polymerization could be carried out without adding a separate polymerization initiator. . As shown in Table 6 of Example 2, the ratio of the peroxide (O = C—O—O) on the cell surface subjected to the corona discharge treatment for 10 seconds was 7.0%, and the corona discharge treatment for 1 second. Since the ratio of the peroxide (O = C—O—O) on the surface of the cell subjected to the treatment is more than 2.8%, the cell subjected to the corona discharge treatment for 10 seconds is used for the graft polymerization. preferable.

  The details of the method of locally hydrophilizing the inner wall of the cell by graft polymerization of a hydrophilic vinyl monomer will be described below. FIG. 9 is a flowchart showing a process for forming a hydrophilic graft polymer on the inner wall of the reaction cell.

Step 1. Cleaning the inner wall of the cell.
Specifically, in the same manner as in Example 1, 600 μl of ethanol was put into the inner wall portion of the cell, left to stand for 24 hours, and after removing the ethanol, the inner wall portion of the cell was cleaned by drying with a vacuum desiccator.
Step 2. Cell local corona discharge treatment in the atmosphere.
Specifically, similarly to the method described in the second embodiment, a corona discharge treatment is performed for 10 seconds on the portion from the bottom surface of the photometric surface inner wall portion 2 surface of the cell to a desired height in the atmosphere.
Step 3. Oxygen removal from hydrophilic vinyl monomer solution.
Specifically, oxygen in the hydrophilic vinyl monomer solution is removed by putting the hydrophilic vinyl monomer solution into a flask, sending nitrogen gas and bubbling.

Step 4. Injection of hydrophilic vinyl monomer solution into the cell.
600 μl of the hydrophilic vinyl monomer solution having a reduced oxygen concentration in Step 3 is injected into the second cell. At this time, hydrophilic vinyl monomers such as acrylamide, sodium vinyl sulfonate, hydroxyl ethyl ester methacrylate, polyethylene glycol methacrylate, polyethylene glycol methyl methacrylate methacrylate, vinyl acetate, glycidyl methacrylate, etc. are used as the hydrophilic vinyl monomer. At least one of the monomers can be used.
Step 5. Confine cell in nitrogen atmosphere.
Specifically, the cell injected with the hydrophilic vinyl monomer in Step 4 is put into a two-necked flask, and nitrogen gas is fed into the place where the lid is capped to make the inside of the flask a nitrogen atmosphere.
Step 6. Freeze vacuum deaeration.
Specifically, by repeating the Freeze-Pump-Thaw cycle 4 times using a rotary pump capable of achieving a vacuum degree of about 10 Pa with liquid nitrogen, the inside of the two-necked flask was frozen and vacuum degassed to form a nitrogen atmosphere. .

Step 7. Graft polymerization by heating.
Specifically, the two-necked flask in Step 6 is placed in a water bath maintained at 50 ° C. and heated to perform graft polymerization.
Step 8. Cell cleaning.
Specifically, the inner wall portion of the reaction cell subjected to graft polymerization in step 7 is washed with pure water, and then the cell is dried by a vacuum desiccator.

By this method, the cell inner wall portion can be locally hydrophilized by graft polymerization. Note that step 1 to step 8 may be performed without performing step 1. FIG. 10 is a schematic cross-sectional view of a photometric surface inner wall portion that has been partially hydrophilized by graft polymerization. A hydrophobic portion 412 and a hydrophilic portion 413 exist on the photometric surface inner wall surface 411 of the cell 410, and a hydrophilic graft polymer 414 exists on the hydrophilic portion 413. A hydrophilic substituent 415 is introduced into the hydrophilic graft polymer. The hydrophilic substituent 415 is replaced by the hydrophilic monomer used. For example, if the hydrophilic monomer is acrylamide, substituents 415 is CONH _2. When the hydrophilic monomer is sodium vinyl sulfonate, the substituent 415 is SO ₃ Na. When the hydrophilic monomer is vinyl acetate, the substituent 415 is OCOCH ₃ . At this time, the hydrophilic portion 413 corresponds to the corona discharge-treated portion of the inner wall portion of the cell. Here, not only the graft polymer 414 but also the hydrophilic group 416 exists. The hydrophilic group 416 includes a hydrophilic substituent 417. The hydrophilic substituent 417 is a highly hydrophilic substituent such as a hydroxyl group, an ether group, a carboxyl group, or a carbonyl group.

  In this example, a 10% aqueous solution of acrylamide was used as the hydrophilic vinyl monomer solution used in step 3 of the flowchart shown in FIG. 9, and the heating time in step 7 of the flowchart was 3 hours. If a hydrophilic vinyl monomer solution is used, the solution concentration and heating time are not limited to the methods of Examples 3-7.

  XPS measurement was performed in the same manner as in Example 2 in order to compare the relative abundance ratios of carbon, oxygen and nitrogen on the cell surface subjected to graft polymerization of acrylamide. In the measurement, a wide scan was performed in the range of 1400 eV to −20 eV with a Pass Energy of 20 eV. Table 8 shows the relative abundance ratios of carbon, oxygen, and nitrogen on the surface of the cell obtained by graft polymerization of acrylamide obtained by X-ray photoelectron spectroscopy (XPS).

  Nitrogen was present at a relative abundance of 1.1% on the surface of the cell subjected to graft polymerization of acrylamide, and the relative abundance of oxygen was 7.9%. As shown in Table 2 of Example 2, nitrogen that was not detected on the cell surface subjected to corona discharge treatment (1 second, 10 seconds) was present on the cell surface subjected to graft polymerization treatment of acrylamide. Was indeed grafted to the cell surface.

  In the same manner as in Example 1, the presence or absence of air bubble adhesion in a cell subjected to graft polymerization treatment of acrylamide was examined. In order to evaluate the deterioration of hydrophilicity in an accelerated manner, the results are shown together with the results of heat treatment for 240 hours in a thermostatic chamber maintained at 75 ° C. in a cell subjected to graft polymerization of acrylamide. Table 9 shows the contact angle and presence / absence of bubbles attached to the cells subjected to graft polymerization of acrylamide.

  As shown in Table 9, the contact angle immediately after the graft polymerization treatment (elapsed time 0 hour) was 55 degrees, but the contact angle after heating at 75 ° C. for 240 hours was 78 degrees. Adherence of bubbles did not occur immediately after the graft polymerization treatment and after 240 hours.

  In addition, 600 μl of pure water was once put in a cell that had been allowed to pass at 75 ° C. for 240 hours, and immersed in water at room temperature, and then the contact angle on the cell surface was measured. The contact angle of the untreated cell surface is 90 degrees, and the contact angle of the cell surface subjected to graft polymerization of acrylamide is 55 degrees. The contact angle of the surface after the cell subjected to the graft polymerization treatment of acrylamide for 240 hours at 75 ° C. is 78 degrees. The contact angle of the cell surface after immersing the acrylamide graft-polymerized cell at 75 ° C. for 240 hours and then immersing in water is 55 degrees. Even after the heat treatment, the same hydrophilicity as that after the graft polymerization treatment was exhibited. Once the cell surface, whose hydrophilicity had been lowered by high-temperature heating at 75 ° C., was immersed in water, the hydrophilicity was restored. In the cell subjected to the graft polymerization treatment of acrylamide, the contact angle of the surface not originally subjected to the corona discharge treatment was 90 degrees, which was the same as the cell surface not subjected to the corona discharge treatment. Therefore, the graft polymerization treatment can be selectively performed only on the portion of the cell that has been subjected to the corona discharge treatment.

  Subsequently, elemental analysis of the cell surface subjected to graft polymerization treatment of acrylamide was performed before and after heat treatment at 75 ° C. for 240 hours. XPS was used for analysis. As described in Table 8, the oxygen content of the surface after the production of the cell subjected to the graft polymerization treatment of acrylamide was 7.9%. The oxygen content of the surface after this cell was heated at 75 ° C. for 240 hours was 6.8%. The decrease in oxygen concentration due to heating is about 10%, and the rate of oxygen decrease is smaller than that of the cell treated with the corona discharge of Example 2 for 10 seconds, and the stability to heat is high.

  The reaction cell of this example was confirmed as a reaction cell for an autoanalyzer, which does not cause bubble adhesion, has stirring stability and transparency, and can prevent cross-contamination of samples and reagents between the cells. .

Example 4 Local Hydrophilization by Graft Polymerization Treatment of Vinyl Acetate As in Example 3, the cell surface was locally hydrophilized by vinyl acetate graft polymerization treatment. In this example, 100% of vinyl acetate was used as the hydrophilic vinyl monomer solution used in Step 3 of the flowchart shown in FIG. 9 of Example 3, and the heating time in Step 7 of the flowchart was 2 hours.

  In order to compare the relative abundance ratios of carbon, oxygen and nitrogen on the surface of the cell subjected to graft polymerization treatment with vinyl acetate, XPS measurement was performed in the same manner as in Example 2. In the measurement, a wide scan was performed in the range of 1400 eV to −20 eV with a Pass Energy of 20 eV. Table 10 shows the relative abundance ratios of carbon, oxygen, and nitrogen on the cell surface evaluated by XPS. The relative oxygen abundance of the cell surface grafted with vinyl acetate was 5.7%.

  As in Example 1, the presence / absence of bubbles in the cells subjected to the graft polymerization treatment of vinyl acetate was examined. In order to accelerate the degradation of hydrophilicity, a cell subjected to graft polymerization treatment of vinyl acetate was stored in a thermostatic bath maintained at 75 ° C. for 240 hours. Table 11 shows changes in the contact angle and bubble adhesion behavior of the cells obtained by graft polymerization treatment of vinyl acetate due to heat treatment.

  As a result, the contact angle after heating at 75 ° C. for 0 hour was 79 °, but the contact angle after heat treatment at 75 ° C. for 240 hours was 85 °. Also, no bubbles were attached after the lapse of 0 hours and 240 hours. The change of the contact angle by heating is as small as 6 degrees, and a relatively stable surface is maintained. In addition, the contact angle of the area | region which was not processed of the corona discharge in the surface in the cell which grafted vinyl acetate was 90 degree | times, and was the same as that of an untreated cell surface. Here again, the graft polymerization treatment was selectively performed only on the portion of the cell that had been subjected to the corona discharge treatment.

  Subsequently, elemental analysis of the cell surface subjected to graft polymerization treatment of vinyl acetate was performed by XPS measurement before and after heat treatment at 75 ° C. for 240 hours. The oxygen content on the cell surface grafted with vinyl acetate was 5.7%. The oxygen content of the surface after heating the cell subjected to the graft polymerization treatment of vinyl acetate at 75 ° C. for 240 hours was 5.6%. The decrease in oxygen due to heating is only 0.1% and is almost negligible. The rate of oxygen reduction is smaller than that of the cell treated with the corona discharge of Example 2 for 10 seconds, and the stability to heat is very high.

  The reaction cell of this example was confirmed as a reaction cell for an autoanalyzer, which does not cause bubble adhesion, has stirring stability and transparency, and can prevent cross-contamination of samples and reagents between the cells. .

Example 5 Local Hydrophilization by Hydrolysis Treatment After Graft Polymerization Treatment of Vinyl Acetate A cell obtained by graft polymerization treatment of vinyl acetate was prepared in the same manner as in Example 4. Thereafter, 600 μl of 1M (mol / l) aqueous sodium hydroxide solution was injected into the cell, and the whole cell was heated at 50 ° C. for 1 hour to hydrolyze the ester group, thereby improving hydrophilicity. At this time, the solution used for the hydrolysis is not limited to an aqueous sodium hydroxide solution, and a general alkaline solution may be used. Moreover, the solution concentration and heating time in that case are not limited to the said reaction conditions.

  In order to compare the carbon, oxygen, and nitrogen content on the cell surface grafted with vinyl acetate, XPS measurement was performed in the same manner as in Example 2. In the measurement, a wide scan was performed in the range of 1400 eV to −20 eV with a Pass Energy of 20 eV. Table 12 shows the relative abundance ratios of carbon, oxygen and nitrogen on the cell surface subjected to hydrolysis treatment after graft polymerization treatment of vinyl acetate evaluated by XPS. The relative oxygen abundance of the cell surface hydrolyzed after the graft polymerization treatment of vinyl acetate was 5.8%.

  Similar to Example 1, the presence or absence of bubbles in the cells subjected to hydrolysis treatment after graft polymerization treatment of vinyl acetate was examined. In order to accelerate the degradation of hydrophilicity, the results are shown together with the result of heat treatment for 240 hours in a thermostatic chamber maintained at 75 ° C. after the graft polymerization treatment of vinyl acetate and the hydrolysis treatment. Table 13 shows the contact angle of the cell subjected to the hydrolysis treatment after the graft polymerization treatment of vinyl acetate and the presence / absence of bubbles.

  The contact angle after heating at 75 ° C. for 0 hour was 71 °, but the contact angle after 240 hours at 75 ° C. was 76 °. No bubbles adhered even after 0 hours and 240 hours. The change in contact angle by heating is as small as 5 degrees, and the hydrophilicity of the cell surface is stable. Moreover, the contact angle of the cell surface hydrolyzed after that is lower than the contact angle of the cell surface which carried out the graft polymerization process of the vinyl acetate of Example 4 (Table 11, Table 13). That is, hydrophilicity can be increased by hydrolysis treatment.

  The reaction cell of this example was confirmed as a reaction cell for an autoanalyzer, which does not cause bubble adhesion, has stirring stability and transparency, and can prevent cross-contamination of samples and reagents between the cells. .

<Example 6> Local hydrophilization by graft polymerization treatment of sodium vinyl sulfonate As in Example 3, the cell surface was locally hydrophilized by graft polymerization treatment of sodium vinyl sulfonate. In Example 6, a 25% aqueous solution of sodium vinyl sulfonate is used as the hydrophilic vinyl monomer solution used in Step 3 of the flowchart shown in FIG. 9 of Example 3, and the heating time in Step 7 of the flowchart is 3 Conducted as time.

  X-ray fluorescence analysis of the cell surface grafted with sodium vinyl sulfonate was performed. As the apparatus, a fluorescent X-ray analyzer System3272 manufactured by Rigaku Corporation was used. As a result, S (sulfur) that was not detected in the untreated cell was detected. From this, it was confirmed that sodium vinyl sulfonate was bound to the cell surface.

  In the same manner as in Example 1, the presence or absence of air bubble adhesion in a cell obtained by graft polymerization treatment of sodium vinyl sulfonate was examined. Further, in order to accelerate the deterioration of hydrophilicity (contact angle), a cell obtained by graft polymerization treatment of sodium vinyl sulfonate was stored in a thermostatic bath at 75 ° C. for 240 hours. Table 14 shows changes in the contact angle and bubble adhesion behavior of the cells obtained by graft polymerization of sodium vinyl sulfonate by heat treatment. As a result, the contact angle after graft polymerization was 69 degrees, and the contact angle after heating at 75 ° C. for 240 hours was 74 degrees. Bubbles did not adhere regardless of heating.

  Further, in the same manner as in Example 3, after a cell subjected to graft polymerization treatment with sodium vinyl sulfonate was heated at 75 ° C. for 240 hours, 600 μl of pure water was placed in the cell and left at room temperature for 24 hours (water immersion). The cell surface contact angle was measured. The contact angle of the untreated cell surface is 90 degrees, and the contact angle of the cell surface obtained by graft polymerization treatment of sodium vinyl sulfonate is 69 degrees. The contact angle of the surface after heating the cell which carried out the graft polymerization process of sodium vinyl sulfonate for 240 hours at 75 degreeC is 74 degree | times. Thus, the cell surface of this example is a stable hydrophilic surface with a contact angle only increasing by 5 degrees even when heated at 75 ° C. The cell subjected to graft polymerization of sodium vinyl sulfonate was heated at 75 ° C. for 240 hours, and then the contact angle of the surface immersed in water was 64 degrees. Once the cell surface, whose hydrophilicity had been lowered by high-temperature heating at 75 ° C., was immersed in water, the hydrophilicity was restored, and the hydrophilicity was higher than that after the graft polymerization treatment. Even after the heat treatment, the same hydrophilicity as that after the graft polymerization treatment was exhibited. In the cell grafted with sodium vinyl sulfonate, the contact angle of the portion not subjected to the corona discharge treatment was 90 degrees, which was the same as the cell surface before the corona discharge treatment. Therefore, also in this case, the graft polymerization treatment selectively selectively hydrophilizes only the region in the cell that has been subjected to the corona discharge treatment.

  The reaction cell of this example was confirmed as a reaction cell for an autoanalyzer, which does not cause bubble adhesion, has stirring stability and transparency, and can prevent cross-contamination of samples and reagents between the cells. .

<Example 7> Local hydrophilization by polymerization treatment of polyethylene glycol methyl ether methacrylate As in Example 3, the cell surface was locally hydrophilized by graft polymerization treatment of polyethylene glycol methyl ether methacrylate. In Example 7, a 10% aqueous solution of polyethylene glycol methyl ether methacrylate was used as the hydrophilic vinyl monomer solution used in Step 3 of the flowchart shown in FIG. 9 of Example 3, and the heating time in Step 7 of the flowchart was used. Was 3 hours.

  In the same manner as in Example 1, the presence or absence of bubbles in a cell obtained by graft polymerization treatment of polyethylene glycol methyl ether methacrylate was examined. In addition, a cell subjected to graft polymerization treatment with polyethylene glycol methyl ether methacrylate was stored in a thermostatic bath at 75 ° C. for 240 hours in order to accelerate the change in hydrophilicity. Table 15 shows the change in the contact angle and the bubble adhesion behavior of the cell obtained by graft polymerization treatment of polyethylene glycol methyl ether methacrylate with the heat treatment. The contact angle immediately after graft polymerization (75 hours of heating at 75 ° C.) was 67 °, but the contact angle after heating at 75 ° C. for 240 hours was 72 °. In the cells subjected to the graft polymerization treatment, no bubbles were attached regardless of the presence or absence of the heat treatment.

  Further, as in Example 3, the cell obtained by graft polymerization of polyethylene glycol methyl ether methacrylate was heated at 75 ° C. for 240 hours, then 600 μl of pure water was placed in the cell and allowed to stand at room temperature for 24 hours. The contact angle of was measured. The contact angle of the untreated cell surface is 90 degrees, and the contact angle of the cell surface obtained by graft polymerization of polyethylene glycol methyl ether methacrylate is 67 degrees. The contact angle of the surface after heating a cell subjected to graft polymerization of polyethylene glycol methyl ether methacrylate for 240 hours at 75 ° C. is 72 degrees. Even when a cell subjected to graft polymerization treatment of polyethylene glycol methyl ether methacrylate is heated at 75 ° C., the contact angle changes only 5 degrees and the hydrophilicity hardly changes.

  The cell subjected to graft polymerization with polyethylene glycol methyl ether methacrylate was allowed to elapse for 240 hours at 75 ° C., and then the contact angle of the surface immersed in water was 61 degrees. Once the cell surface, whose hydrophilicity had been lowered by heating at 75 ° C., was immersed in water, the hydrophilicity was restored, and the hydrophilicity increased more than immediately after graft polymerization. In addition, in the cell grafted with polyethylene glycol methyl ether methacrylate, the contact angle of the surface or part not originally subjected to corona discharge treatment remained 90 degrees, which was the same as that of the cell surface not treated with corona discharge. . Therefore, the graft polymerization treatment can be selectively performed only on the portion of the cell that has been subjected to the corona discharge treatment.

  The reaction cell of this example was confirmed as a reaction cell for an autoanalyzer, which does not cause bubble adhesion, has stirring stability and transparency, and can prevent cross-contamination of samples and reagents between the cells. .

<Embodiment 8> Embodiment in Automatic Analyzer FIG. 11 is a diagram showing a configuration example of an automatic analyzer according to the present invention. Next, the basic operation will be described. Reference numeral 1 denotes a sample storage unit, and one or more sample containers 25 are arranged in the mechanism 1. Here, an example of a sample disk mechanism that is a sample storage unit mechanism mounted on a disk-shaped mechanism unit will be described. However, as another form of the sample storage unit mechanism, a sample generally used in an automatic analyzer It may be in the form of a rack or sample holder. The sample here refers to a solution to be inspected used for reacting in a reaction vessel, and may be a collected sample stock solution or a solution obtained by subjecting it to a processing such as dilution or pretreatment. . The sample in the sample container 25 is extracted by the sample nozzle 27 of the sample supply dispensing mechanism 2 and injected into a predetermined reaction container. Reference numeral 5 denotes a reagent disk mechanism. This mechanism 5 includes a large number of reagent containers 6. The mechanism 5 is provided with a reagent supply dispensing mechanism 7, and the reagent is sucked and injected into a predetermined reaction cell by the reagent nozzle 28 of the mechanism 7. Reference numeral 10 denotes a spectrophotometer, and 26 denotes a light source with a condensing filter. Between the spectrophotometer 10 and the light source 26 with a condensing filter, a reaction disk 3 that accommodates a measurement target is disposed. On the outer periphery of the reaction disk 3, for example, 120 reaction cells 4 having a hydrophilic portion and a hydrophobic portion on the inner wall portion are installed. This hydrophilic portion is limited to the closed portion side of the reaction cell, but has an area sufficiently including the photometric region. On the other hand, the hydrophobic portion is on the opening side of the reaction cell, and prevents wetting due to the capillary action of the solution. Further, the entire reaction disk 3 is held at a predetermined temperature by a thermostatic chamber 9. Reference numeral 11 denotes a reaction cell cleaning mechanism, and the cleaning agent is supplied from the cleaning agent container 13. Reference numeral 19 is a computer, 23 is an interface, 18 is a Log converter and A / D converter, 17 is a reagent pipetter, 16 is a washing water pump, and 15 is a sample pipettor. Reference numeral 20 denotes a printer, 21 denotes a CRT, 22 denotes a floppy disk or hard disk as a storage device, and 24 denotes an operation panel. The sample disk mechanism is controlled and driven by the drive unit 200, the reagent disk mechanism is driven by the drive unit 201, and the reaction disk is controlled and driven by the drive unit 202, respectively. Each part of the automatic analyzer is controlled by a computer via an interface.

  In the above configuration, the operator inputs analysis request information using the operation panel 24. The analysis request information input by the operator is stored in a memory in the microcomputer 19. The sample to be measured that is placed in the sample container 25 and set at a predetermined position of the sample disk mechanism 1 is supplied to the sample pipettor 15 and the sample supply dispensing mechanism 2 according to the analysis request information stored in the memory of the microcomputer 19. A predetermined amount is dispensed into the reaction cell by the sample nozzle 27. The sample nozzle 27 is washed with water. A predetermined amount of reagent is dispensed into the reaction cell by the reagent nozzle 28 of the reagent supply dispensing mechanism 7. After the reagent nozzle 28 is washed with water, it dispenses a reagent for the next reaction cell. The mixed solution of the sample and the reagent is stirred by the stirring rod 29 of the stirring mechanism 8 or the ultrasonic element. The stirring mechanism 8 sequentially stirs the liquid mixture in the next reaction cell. If a reaction cell composed of a hydrophilic part and a hydrophobic part is used, the bubbles encased by agitation will not be adsorbed to the photometric region on the inner wall surface of the cell, so that analysis data will not be affected.

  The reaction cell 4 is maintained at a constant temperature by a thermostat 9 and serves as both a reaction and a photometric container. In the reaction process, light is supplied from a light source 26 with a condensing filter, and the hydrophilic portion of the reaction cell is measured by a spectrophotometer 10 at regular intervals and mixed using one or more set wavelengths. The absorbance of the liquid is measured. By using a light source with a condensing filter at the time of measurement, only the hydrophilic portion of the reaction cell can be selectively transmitted.

FIG. 16 is a peripheral view of the spectrophotometer of the automatic analyzer. The example which uses a condensing lens as a condensing filter is shown. The light emitted from the light source 32 travels in the direction of the arrow 38, is collected by the condenser lens 34, passes through the photometric region 36 of the reaction cell, and is split by the spectrophotometer 10. At this time, the light spreading width 33 emitted from the light source is L ₁ and is condensed by the condenser lens and converted into the light spreading width L ₂ , and L ₂ <L ₁ is satisfied. Thereby, the size S ₁ of the photometric region 36 can be made smaller than the size S ₂ of the hydrophilic region 37. By using a condensing lens and making S ₁ <S ₂ , photometry can be performed without bubble adhesion.

FIG. 17 shows an example in which a slit 45 is used instead of the condenser lens 34 as a condenser filter. The size of the slit windows 46 and S _3, as compared to the size S ₂ of the foregoing hydrophilic region can be photometry does not occur bubble adhesion by the S 3 _{<S 2.}

  Since the bubble adhesion does not occur in the hydrophilic part of the reaction cell, there is little variation in absorption measurement and the accuracy is high. Similarly, since there is a hydrophilic portion on the inner wall portion of the reaction cell, bubbles that become a detection hindrance are not adsorbed on the photometric surface and bottom surface of the reaction cell, so that the region through which light passes through the reaction cell can be set near the bottom surface. Therefore, the amount of sample and reagent put into the reaction cell can be greatly reduced, which is useful from the viewpoint of reducing the running cost of the user. By using the reaction cell of the present invention, the amount of the reaction solution including the reagent and the sample solution can be reduced to 1/2 or less than the conventional amount, and automatic analysis can be performed.

  The measured absorbance is taken into the computer 19 via the Log converter and A / D converter 18 and the interface 23. The absorbed absorbance is converted into a concentration value, and the concentration value is stored in a floppy disk or hard disk 22 or output to the printer 20. In addition, inspection data can be displayed on the CRT 21. The reaction cell 4 that has been measured is washed with water by a reaction vessel washing mechanism (nozzle arm) 11. After the washing is completed, water is sucked by the suction nozzle 12 and then used sequentially for the next analysis.

  Thus, as a result of mounting the reaction cell 4 having a hydrophilic portion and a hydrophobic portion on the inner wall portion and performing automatic analysis, there was no phenomenon in which the test solution climbed to the opening of the reaction cell by capillary action. That is, cross-contamination and cross-contamination mixed with reagents in adjacent reaction cells did not occur. Moreover, since there was no bubble adsorption, the measurement error was reduced. On the other hand, cross-contamination and cross-contamination occurred when the inner wall of the reaction cell was made hydrophilic from the bottom to the opening.

  This example shows an example in which automatic analysis was performed when the amount of the reaction solution was minimized using a reaction cell in which a portion from the bottom surface of the inner wall of the photometric surface to a desired height was locally hydrophilized. However, the present invention is not limited to the size of the region to be hydrophilized or the amount of the reaction solution. In addition, if the reaction cell has a high hydrophilicity on the inner wall portion of the photometric region, it is possible to carry out stable automatic analysis without causing bubbles and without causing cross-contamination and cross-contamination.

  Furthermore, when water is poured into the reaction cell in the same manner as in Examples 2 to 7, the hydrophilicity of the hydrophilic portion of the cell can be further increased, and a more stable analysis can be performed. The water used for water injection here may be pure water, but is not limited to pure water, and may be a solution to which an additive having an effect of further improving hydrophilicity is added. In order to obtain the same effect, not only liquid but also fine powder, mist, or gas may be used. Therefore, it is desirable to use an automatic analyzer after the reaction cell is immersed in water.

1 ... Sample storage unit, 2 ... Sample supply dispensing mechanism, 3 ... Reaction disk, 4 ... Reaction cell, 5 ... Reagent disk mechanism, 6 ... Reagent container, 7 ... Reagent supply dispensing mechanism, 8 ... Agitation mechanism, 9 ... constant temperature bath, 10 ... spectrophotometer, 11 ... reaction cell washing mechanism, 12 ... suction nozzle, 13 ... detergent container, 15 ... sample pipetter, 16 ... wash water pump, 17 ... reagent pipettor, 18 ... Log Converter and A / D converter, 19 ... computer, 20 ... printer, 21 ... CRT, 22 ... floppy disk or hard disk, 23 ... interface, 24 ... control panel, 25 ... sample cell, 26 ... light source with condensing filter, 27 ... Sample nozzle, 28 ... Reagent nozzle, 29 ... Stirring rod, 32 ... Light source, 33 ... Light spread width, 34 ... Condensing lens, 35 ... Light spread width, 36 ... Photometry area, 37 ... Hydrophilic area, 38 ... light direction, 40 ... photometry area, 41 ... photometry surface, 42 ... photometry surface, 45 ... slit 46 ... Slit window, 50 ... Cell block, 51 ... Single cell, 60 ... Cell block, 61 ... Cell, 62 ... Photometric surface, 70 ... Sample disk mechanism, 71 ... Sample cell, 72 ... Sample cell cleaning mechanism, 73 ... Suction Nozzle, 101 ... long side, 102 ... short side, 103 ... height, 111 ... non-photometric surface outer wall, 112 ... non-photometric surface inner wall, 113 ... photometric surface outer wall, 114 ... photometric surface inner wall, 115 ... bottom surface, 116 ... non Half length of photometric surface, 117 ... length of photometric surface, 118 ... inner wall height, 119 ... boundary line, 120 ... corona discharge treatment part, 130 ... closed part, 140 ... opening part, 150 ... single cell thickness , 160 ... area, 161 ... boundary line, 162 ... boundary line, 200 ... drive unit, 201 ... drive unit, 202 ... drive unit, 211 ... corona discharge source, 212 ... wiring, 213 ... anode, 214 ... corona discharge anode rod Electrode, 216 ... wiring, 217 ... ground, 218 ... cathode plate, 300 ... driving unit, 301 ... driving unit, 410 ... cell, 411 ... photometric surface inner wall surface, 412 ... hydrophobic part, 413 ... hydrophilic part , 414 ... hydrophilic graft polymer, 415 ... hydrophilic substituent, 416 ... hydrophilic group, 417 ... hydrophilic substituent, 511 ... oxygen relative abundance (%), 512 ... CO bond introduction rate (%), 513 ... air bubbles Adhesion rate (%)

Claims (5)

In the manufacturing method of the reaction cell for automatic analyzer made of transparent resin,
Inserting an electrode into the inside of the reaction cell made of resin and covering the outside of the inner wall surface to be hydrophilized on the bottom side of the reaction cell with an electrode without covering the outside near the opening of the reaction cell with the electrode When,
Corona discharge using the electrode inside the reaction cell and the electrode outside the reaction cell, and imparting hydrophilicity to the inner wall surface inside the region covered by the electrode outside the reaction cell; A method for producing a reaction cell for an automatic analyzer, comprising:   The automatic analyzer according to claim 1, wherein the corona discharge imparts hydrophilicity to a region between the two electrodes while keeping a region not covered by the electrode outside the reaction cell hydrophobic. Method for manufacturing a reaction cell. Introducing a peroxide into a desired region excluding the opening side of the resin reaction cell inner wall surface;
Adding a hydrophilic vinyl monomer solution in the reaction cell after the introduction of the peroxide;
A step of bringing the inside of the reaction cell into a nitrogen atmosphere after the addition of the hydrophilic vinyl monomer;
Having a thermal graft polymerization process under a nitrogen atmosphere,
A method for producing a reaction cell for an automatic analyzer, wherein hydrophilicity is imparted to the desired region excluding the opening side of the inner wall of the reaction cell.   The method for producing a reaction cell for an automatic analyzer according to claim 3, wherein in the step of introducing the peroxide into a desired region on the inner wall surface of the reaction cell, the region is subjected to corona discharge treatment.   The method for producing a reaction cell for an automatic analyzer according to claim 3, wherein hydrophilicity is imparted to the desired region while keeping the inner wall of the reaction cell on the opening side hydrophobic.

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