JP2007309938A - Needle unit for sample injection, and sample suction/cleaning device of syringe using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sample injection method for reducing carry-over in high-sensitivity measurement in liquid chromatography, improving the throughput, and securing accuracy of quantitative determination. <P>SOLUTION: The needle of the sample injection comprises a tip, a root, and a solvent-holding section between them, and has two inside diameters. The solvent-holding section has a large inside diameter section, so that the sucked sample solution remains in the needle. As a result of this, the sample can be prevented from coming into contact with part of sample suction device, such as the syringe body, the inner surface of a tube, or the tip of a plunger. For preventing nonspecific specimen adsorption, the inner wall of flow channel is polished effectively. The method of sample injection for reducing carryover effect is also described. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a needle unit for sample injection of an autosampler, and a sample suction and cleaning apparatus and method for a syringe using the needle unit.

  In recent years, there is a growing need for high sensitivity and high throughput mass spectrometry in the biomedical and pharmaceutical fields. As the detection sensitivity of mass spectrometers improves, efforts to reduce the carryover of specimens in continuous injection using an autosampler are becoming more and more necessary to ensure data accuracy. Despite significant efforts to establish needle and syringe cleaning methods to reduce carryover, it has been difficult to overcome carryover problems.

  For example, as shown in FIG. 4A, a sample injection syringe 5 used in a conventional autosampler is adapted to fit a sample injection needle 1, a barrel 2 connected to the sample injection needle 1, and an inner wall of the barrel. And a plunger 3 provided in Further, as shown in FIG. 4B, the cleaning device for the sample injection syringe 5 includes an injection port 7 for inserting the needle 1 of the syringe 5, an injection valve 9 connected to the injection port 7, and the injection The cleaning solvent supply means 15A and B are connected to the valve 9 via a trident joint 11 and pipe lines 13A and 13B, respectively.

  The washing solvent supply means 15A, B are connected to the solvent containers 25A, B, and the pumps 27A, B connected to the containers, respectively, for feeding the solvent to the injection valve 9 via the lines 13A, B and the three-way joint 11. Have The injection valve 9 is connected to the washing system pipe, the injection port 7, the separation column 29, and the eluent adjustment mixer 31, respectively, to wash the injection syringe 5, to inject the sample into the column 29, from the mixer 31. A switching function for selectively supplying the eluent. In the figure, 33 is a detector connected to the outlet of the column 29, and 37A and B are pumps for supplying the eluent of the containers 39A and B to the mixer 31, respectively.

  The sample is supplied to the sample injection syringe 5 by immersing the needle 1 in the sample solution, pulling up the plunger 3 in the syringe, and sucking a predetermined amount of sample into the barrel of the syringe. Next, the needle 1 of the sample injection syringe 5 is inserted into the injection port 7, the injection valve 9 is switched to the load path (dashed line of the valve 9), the sucked sample is injected into the loop, and the injection valve is injected into the injection path (valve). 9), the sample is introduced into the analysis system. Thereafter, the column analysis operation of the sample is performed according to a conventional method.

  In order to clean the sample injection syringe 5 and its related system, the loop of the valve 9 is aligned with the injection port 7 in which the injection syringe 5 is inserted, and the cleaning mode is set as shown in FIG. Next, the cleaning solvents A and B are sequentially supplied from the injection valve 9 to the injection port 7 via the lines 13A and B and the trident joint 11 by the pumps 27A and B from the containers 25A and B. The injection syringe 5 is washed by immersing the needle 1 of the injection syringe 5 into the solvent of the injection port 7 and sucking and discharging the solvent through the needle 1 into the cylinder 3.

  In the above apparatus, since the sample is first sucked into the barrel 2 from the needle 1 with respect to the injection syringe 5, the sample is discharged to the connecting portion between the barrel 2 and the needle 1 and the inner wall of the barrel 2 after the sample is discharged (injected). There was a problem that it remained, and even after washing with a solvent, it affected the next sample measurement as a carry-over. In the above washing system, since the solvents A and B are supplied to the injection valve 9 via the three-pronged joint 11, for example, when the solvent A is supplied by the pump 27 A, another solvent A is supplied via the three-pronged joint 11. As a result, there is a problem in that the same phenomenon occurs when the pump 27B is operated and the cleaning efficiency of the solvents A and B is deteriorated. As for the injection port 7, when the solvent is sucked into the syringe 5 and washed after the sample is deposited (discharged), the remaining sample is mixed into the washing solvent and contaminates the inside of the syringe, the inside of the needle unit, and the outside. There is a problem that it ends up.

  As described above, the existing autosampler performs aspiration / injection of the sample solution with a needle connected directly to a suction device (usually a syringe) or through a flexible tube. In this case, it is difficult to completely replace the sample with the washing solvent, and the washing solvent supply system also has a problem in washing efficiency such as mixing of solvents, so that complete solution is difficult. It was.

  An object of the present invention is to provide a needle unit of a sample injection syringe that solves the above problems and minimizes carryover of the sample as much as possible, a sample suction method using the same, and a cleaning solvent It is possible to provide a needle unit of a sample injection syringe, a sample suction method, a cleaning device, and a cleaning method using the unit, which can avoid contamination of the sample, expansion of contamination due to the remaining sample, and the like.

  In order to achieve the above object, the present inventor has discovered that the contact portion of the parts of the sample suction device such as the syringe body, the inner wall surface of the tube, and the tip of the plunger is the cause of carry-over, and the sucked sample solution is By improving the structure of the needle so that it stays within the needle and using this improved needle in combination with a newly developed efficient cleaning method, carry-over was almost completely prevented. That is, for example, in the conventional sample injection syringe (FIG. 4A), the sample is sucked into the barrel 2 through the needle 1, so even if the sample is replaced and washed with a washing catalyst after the sample is injected, It was found that the sample remaining in the inner wall of the barrel 2 and the needle 1 and particularly in the barrel 2 having a large surface area is a major cause of carryover. The present invention has been made on the basis of such knowledge, and is sufficient to store a sample necessary for one detection in a suction needle portion having an inner diameter and a length necessary for sample suction and injection. The storage needle portion having a large volume is continuously provided without a seam, thereby preventing the sample from being sucked into the barrel, thereby solving the above problem.

That is, the invention claimed in the present application is as follows.
(1) A needle unit connected to a syringe as a sample suction device directly or via a conduit, the needle unit having a hole end for sucking a sample, and a suction needle composed of a thin tube And a liquid-retaining needle part comprising a thin tube having an inner diameter B larger than the inner diameter A of the thin-tube of the suction needle part connected to the suction needle part seamlessly. A needle unit for sample injection, wherein the section has a capacity sufficient to hold a sample to be injected.
(2) The needle unit according to (1), wherein the inner diameter A is in the range of 0.15 to 0.45 mm.
(3) The needle unit according to (1) or (2), wherein the inner diameter B is in the range of 0.15 to 1.0 mm.
(4) the suction needle of the length _{L 1} is 35.8mm, the inner diameter A is 0.42 mm, the length _{L 2} of the liquid distillate needle portion 22.5 mm, an inner diameter B is 0.7 mm (1 ) Needle unit.
(5) When a sample is sucked into the sample injection syringe having the needle unit according to any one of (1) to (4), the solvent, air, sample, and air are sequentially introduced from the opening end of the suction needle unit. A sample suction method for a sample injection syringe, wherein the sample is sucked so as to form each layer, and the sample layer is retained in a liquid distillation needle portion below the barrel of the syringe.
(6) A sample injection syringe using the needle unit according to any one of (1) to (4).
(7) The sample injection syringe according to (6), an injection port for inserting the sample injection syringe, an injection valve connected to the injection port, and a plurality of pipes connected to the injection valve via a pipe line An apparatus having a cleaning solvent supply means, wherein a side port for injecting the cleaning solvent is provided in a barrel side wall of the sample injection syringe, and a cleaning line switching valve is provided in a pipe line between the injection valve and the cleaning solvent supply means The sample injection according to (6), characterized in that a pipe for supplying the cleaning solvent to the inner cylinder of the injection port and the side port provided on the barrel side wall is provided through the switching valve. Cleaning apparatus of the syringe.
(8) The injection port has an insertion hole into which the sample injection syringe is inserted, an inner cylinder having the insertion hole at the bottom, and an upper end higher than the inner cylinder provided at intervals around the insertion cylinder. The cleaning apparatus according to (7), comprising an outer cylinder and a cleaning liquid discharge port provided at a bottom of the outer cylinder.
(9) A plurality of cleaning solvents are pumped through the switching valve and injection valve to the injection port, syringe side port, and sample discharge flow path for cleaning, and the cleaning solvent overflows the inner cylinder of the injection port. And cleaning the outside of the needle by inserting and removing the needle into and from the solvent in the inner cylinder.

  According to the sample injection needle unit and the syringe of the present invention, the sucked sample is retained in the large-diameter portion (storage needle portion) of the needle, and is then injected through the small-diameter suction needle portion. Since the sample does not enter the barrel part on the upstream side of the part and the sample can be supplied only to the needle part, there are few contaminated parts by the residual sample, and the syringe and related equipment cleaning efficiency after sample injection Can be significantly increased. In addition, if the sample is sucked and injected with an air sandwich using the needle unit, contamination of the apparatus by the sample can be further reduced.

  Further, according to the cleaning device of the present invention, a plurality of cleaning solvents are introduced from the injection port and the side injection port of the syringe, and the cleaning solvent is supplied to the needle portion and the barrel portion of the syringe from different pipes for cleaning. Therefore, it is possible to prevent a decrease in cleaning efficiency due to mixing of cleaning solvents.

  FIG. 1 is an explanatory diagram of a needle unit used in the present invention. The needle unit 1 includes an aspirating needle portion 1A having an open end 4 for aspirating a sample, and an inner diameter A of the aspirating needle portion 1A that is seamlessly connected to the aspirating needle portion 1A. It has a liquid-retaining needle part 1B having a large inner diameter B, and an adapter 6 provided at the end of the liquid-retaining needle part 1B for connecting to the suction device. The liquid distilling needle portion 1B has a capacity sufficient to hold the entire injected sample. The needle unit 1 is connected to a suction device and is used for suction and injection of a sample. The suction device (syringe 5) is connected to a barrel 2 and a barrel 2 as shown in FIG. The upper end of the liquid retention needle 1B is attached to the lower end of the barrel 2 via the adapter 6 shown in FIG. The sample is aspirated and injected by moving the plunger 3 of the syringe 5 up and down. At the time of sample suction, the sample is sucked up from the suction needle portion 1A to the liquid retention needle portion 1B, but the diameter of the liquid retention needle portion 1B is large enough to hold the entire sample. Therefore, the influence of the remaining sample after washing on the inner wall of the barrel, the plunger, etc. can be eliminated, and the carry-over of the sample during washing can be significantly reduced.

  When a sample is sucked using the syringe 5 of the present invention, as shown in FIG. 3, each layer is formed in the order of solvent, air (air), sample, and air from the opening end of the suction needle portion 1A. Furthermore, it is preferable to suck the sample in the form of a so-called air sandwich. In this case, the volume of the upper and lower air layers is preferably 1 to 5 μl. From the above viewpoint, the inner diameter of the suction needle portion 1A is preferably in the range of 0.15 to 0.45 mm. If the inner diameter of the suction needle portion 1A is too small, the sample is not sucked smoothly, and if it is too large, the solvent and air layers are mixed, or the sample is diluted with the solvent in reverse and the stable sample Injection is no longer performed.

On the other hand, the needle portion 1B for liquid distillates need only have sufficient capacity to hold a sample to be injected at one time. Specifically, the length L ₂ is 15～100Mm, the inner diameter B 0 The range of 15 to 1.0 mm is preferable. If the inner diameter B is too small, the volume cannot be taken sufficiently, and if it is too large, even if the air sandwich suction operation is performed at the time of sample suction, the air layer may move and the air sandwich may not be performed. May cause reversal of solvent layer and sample layer.

  The suction needle portion 1A and the liquid retention needle portion 1B are preferably constituted by a single stainless steel tube through a seamless step portion. In order to prevent nonspecific specimen adsorption, the inner wall of the needle is preferably subjected to electrolytic polishing. Electrolytic polishing of the inner wall of the needle is particularly effective in preventing needle contamination and carryover because a new smooth surface is formed on the metal surface by electrolysis and a uniform oxide film is formed.

  As long as the adapter 6 provided at the end (upper end in the drawing) of the liquid-retaining needle unit 1B can connect the end of the needle unit 1B to a suction device, usually a suction unit of a syringe in an airtight manner, Any shape and material may be used. The material is usually a fluororesin, touch-resistant rubber, or a stainless steel caulking joint.

Next, a method for using the needle unit of the present invention will be described in detail with reference to the drawings.
FIG. 2 is an explanatory diagram of a cleaning system for an apparatus using the needle unit of the present invention.
This apparatus includes a sample injection syringe 5 having the needle unit 1 shown in FIG. 1, an injection port 7 for inserting the sample injection syringe 5, an injection valve 9 connected to the injection port 7, and the injection valve 9. 4 is the same as the conventional apparatus shown in FIG. 4 except for the following points. That is, the injection port 7 is more than the insertion hole 21 into which the sample injection syringe 5 is inserted, the inner cylinder 17 having the insertion hole 21 at the bottom, and the inner cylinder 17 provided around the periphery thereof. It consists of an outer cylinder 19 having a high upper end and a cleaning liquid discharge port 23 provided at the bottom of the outer cylinder 19, and the inner cylinder 17 has dimensions sufficient for the needle 1 of the injection syringe 5 to be inserted and cleaned. The outer cylinder 19 has a height higher than that of the inner cylinder in order to allow the cleaning solvent to overflow from the upper end of the inner cylinder 17.

  On the other hand, a side port 41 for injecting a cleaning solvent is provided on the side wall of the barrel 2 of the syringe 5, and a cleaning line switching valve 40 is provided in a pipe line between the injection valve 9 and the cleaning solvent supply means 15A, 15B. And pipes 42, 46, and 48 for supplying the cleaning solvent to the inner cylinder 17 of the injection port 7 and the side port 41 provided on the barrel side wall through the switching valve 40, respectively. . A sleeve (not shown) is provided at the joint between the injection port 7 and the injection valve 9 so that the sleeve can be sealed when the needle is lowered to the lower end.

  In order to clean the sample injection syringe and related equipment, the cleaning solvent is introduced from the containers 25A, B to the injection port 7 via the injection valve 9 by the pumps 27A, B, but is the same as the apparatus of FIG. The solvent can be supplied to the injection port 7 through the switching valve 40 as described above, and the solvent can be supplied directly from the side port 41 on the side wall of the barrel into the barrel 2 through the same switching valve 40. Is different.

  In order to wash the syringe 5 and its related system, the loop of the valve 9 is aligned with the injection port 7 in which the syringe 5 is inserted, and the washing mode is set as shown in FIG. Next, the cleaning solvents A and B are sequentially supplied from the injection valve 9 to the injection port 7 via the lines 13A and B and the trident joint 11 by the pumps 27A and B from the containers 25A and B. The injection syringe 5 is washed by immersing the needle 1 of the injection syringe 5 into the solvent of the injection port 7 and sucking and discharging the solvent through the needle 1 into the syringe 5. The waste liquid after washing is discharged out of the system from the outlet 23 of the outer cylinder 19 or discharged to a discharge port (not shown). The line 13 </ b> C connected to the three-way joint 11 functions as a waist line for discharging waste liquid when the sample remaining in the injection port 7 and the valve 9 is first discharged. This is useful in preventing contamination by the remaining sample when the syringe 5 is repeatedly washed with a solvent.

  According to the above apparatus, since the cleaning solvent introduced into the syringe 5 through the switching valve 40 and the injection valve 9 is only one kind passing through the pipe line 42, the mixing of the solvents due to the backflow is avoided as in the conventional apparatus. be able to. Further, it is possible to change the supply flow rate of the cleaning solvent by providing the throttle 44 in the pipe line 43 for discharging the sample. On the other hand, the solvent supplied to the side port 41 of the syringe 2 through the pipes 46 and 48 and the tee (T-shaped joint) 50 via the switching valve 40 does not pass through the injection port 7 but directly into the barrel 2. Since it is supplied, contamination with other solvents and contamination (carry over) by the remaining sample can be extremely reduced. Further, the switching of the flow path of the cleaning solution to the injection port 7 and the side port 41 is performed by the switching valve 40, so that no solvent or sample is mixed by backflow, and the tee 50 is provided close to the sample injection syringe 5. Therefore, the solvent can be replaced quickly.

    As described above, in the present invention, the syringe 5 can be washed by supplying the solvent from the side port 41 into the barrel 2 by the pumps 27A and B via the lines 46 and 48 and the tee 50. It is possible to eliminate the disadvantage that the sample comes into contact with the problematic needle part, syringe parel part, plunger tip, etc., especially the sample adsorbs on the parel part and remains easily even after washing. Furthermore, in the present invention, in addition to increasing the internal volume of the liquid-retaining needle portion 1B so that the sample does not come into contact with the barrel portion of the cylinder, the inner surface of the needle portion is also seamlessly integrated, and the inner area is reduced. The cleaning efficiency can be further increased by electropolishing the inner surface of the needle portion in order to reduce the size. Further, if the sample is sucked into the air sandwich as described above when sucking the sample, the sample does not contact the plunger tip or the like, and the carry-over rate of the sample can be further reduced.

  Next, an embodiment of the present invention using the needle unit of FIG. 1 and the cleaning system of FIG. 2 will be described. In FIG. 2, the solvents W1 and W2 in the containers 25A and 25B indicate washing solvents. Among these, W1 is the same solvent as the initial mobile phase in the case of conditioning the column before starting the gradient in liquid chromatography, for example. Moreover, W2 can use the solvent with a high washing | cleaning effect with respect to a use sample. These solvents can be used not only in one type but also in several types.

The operation of the cleaning device of the present invention includes (1) conditioning of the syringe, (2) suction of the sample, (3) cleaning of the injection valve and cleaning of the outside of the needle, (4) solvent discharge from the injection port, (5) sample Injection, (6) Westline cleaning, (7) Partial cleaning in syringe, (8) Full stroke cleaning in syringe, (9) Pump cleaning in syringe, (10) Valve cleaning of injection valve, (11 ) Valve channel switching cleaning and the like are described below, but the present invention is not limited to these.
(1) Conditioning of the syringe 5 The pump 27A is operated, the solvent W1 is filled with the solvent 15A via the switching valve 40, and then the syringe 5 is moved. Only the tip is inserted into the inner cylinder 17 of the injection port 7, and then the plunger 3 of the syringe 5 is moved up and down to suck and discharge the solvent W <b> 1 in the syringe 5. Expel the air.
(2) Sample suction After a small amount of air is sucked into the tip of the needle suction section 1A, the needle is inserted into the sample container (vial), the sample is sucked, and then air is put into the tip so that the sample is sandwiched with air. Inhale.
(3) Loop cleaning and needle outer side cleaning The injection valve in FIG. 2 is switched to the load (broken line) path, and the solvent W2 is pumped by the pump 27B through the switching valve 40 and the injection valve 9 to the inner cylinder 17 of the injection port 7. To overflow. Since the solvent W2 is a highly washable solvent, the route through which this solvent has passed can be washed. The needle 1 is washed outside by inserting the needle into the solvent in the cylinder in the injection port and making a stroke up and down. At this time, the sample is already held in the needle, but since the lower end side is isolated by the air layer, the sample does not diffuse into the washing solvent W2. Next, the solvent W1 is made to flow through the same path by the pump 27A, and the above path is conditioned. Similarly, the needle is inserted into the inner cylinder 17 and moved up and down to condition the outside of the needle, and then the position of the injection valve 9 is adjusted. To the original position (injection).
(4) Discharge of the solvent by gravity from the injection port 7 With the pumps 27A and 27B stopped, the solvent in the inner cylinder of the injection port 7 is discharged through the injection valve 9 and the discharge line 44 with the water head pressure.
(5) Sample injection For sample injection, the needle suction part 1A is inserted to the lower end of the injection port 7 and pressed so that there is no gap at the lower end of the needle, and the position of the injection valve 9 is switched. Then, the route of the load (broken line) is taken, and then the plunger 3 of the syringe 5 is lowered, and after the sample is injected, the position of the injection valve 9 is switched back to the original state.

(6) Washing of the waist line 43 Since the injected sample may be partially discharged into the line 43 in the injection valve 9, the line 43 may be dirty. Therefore, when the injection is completed, the pump 27B is operated with the needle as it is, the solvent W2 is flowed, the injection valve 9 is washed through the line 42, and the waste liquid is discharged from the line 44.
(7) Partial cleaning inside the syringe After inserting the needle shallowly into the inner cylinder of the injection port 7 and filling the inner cylinder 17 with the solvent W2 from the pump 27B, the sample previously used in the needle is sandwiched with an air layer. Then, the cleaning solvent W2 is sucked by the total volume, and then the syringe 5 is moved to the discharge port to discharge the solvent. Here, only the part contaminated with the sample of the syringe is cleaned in advance, but not only the cleaning solvent is supplied to the injection port 7 but also the cleaning inside the injection valve 9 is also performed.
(8) Full-stroke cleaning inside the syringe The solvent is sucked in the same process as the above-mentioned cleaning inside the syringe. At this time, the plunger 3 is sucked in full stroke, and the suction and extrusion are repeatedly washed.
(9) Pump cleaning in the syringe The syringe 5 is moved to the solvent discharge port, the plunger 3 of the syringe is slid to the opening position of the side port 41, the solvent W2 is sucked through the switching valve, and the solvent W2 is removed. Rinse into a syringe for cleaning.
(10) Cleaning the injection valve 9 The syringe 5 is moved to the injection port 7 and the needle is inserted to the lower end of the injection port. Next, the plunger 3 of the syringe 5 is slid to the position 41 where the side port is opened, and the solvent W2 is supplied from the pump 27B, and the syringe 5 and the injection valve 9 are washed through the side port 41 of the syringe. Next, the pump 27A is operated, and the syringe 5 and the injection valve 9 are conditioned by flowing the solvent W1 in the same manner as described above. Next, the plunger and the syringe 5 are returned to their original positions.
(11) Valve flow path switching cleaning The solvent W2 is flowed to the injection valve 9 via the line 42 to clean the inside of the valve. At this time, the position of the injection valve is switched to clean the flow path in the valve. The washing solvent W1 is flowed by the pump 27A to the injection valve via the line 42 to condition the valve. Next, the position of the injection valve 9 is switched to clean the flow path in the valve, and then the position of the injection valve 9 is returned to the original position.

Measurement of Carryover Rate in Needle of the Present Invention In order to evaluate the performance of the needle unit of the present invention, three kinds of compounds, reserpine, ibuprofen and chlorhexidine, were analyzed by HPLC / mass spectrometry with the following setup.
Mass spectrometer API 5000 (Applied Biosystems / MDS Sciex, Applied Biosystems); Autosampler HTC-PAL (CTC Analytics, AG); Pump Agilent 1100 binary pump (Agilent Technology); Elution mode isocratic at 0.2 or 0.25 ml / min; wash 1 (W1) Solvent acetonitrile: 2-propanol / 8: 2; wash 2 (W2) Solvent Same as mobile phase; Diluter solvent: acetonitrile containing 1% formic acid; Injection volume: 10 μl; The column temperature, room temperature, and other conditions are as follows.

ESI, ACN, Q1 and Q3 indicate electrospray ionization, acetol, tolyl, quadrupole 1, and quadrupole 3, respectively. Cadenza and Unison are trade names in the intact column.

In this example, the AMR cleaning system was set up to clean the inner and outer surfaces of the needle and the lumen of the syringe body (Fig. 2), and the degree of carryover was compared with that of the conventional needle (22s gauge x 58 mm in length). Comparison was made with the needle of the present invention shown (length L ₁ 35.8 mm of suction needle 1A, inner diameter A 0.42 mm, length L ₂ 22.5 mm of liquid distillation needle 1B, inner diameter B 0.7 mm).
1. Rinse syringe 5 with solvent W2.
2. Sandwich suction of sample solution (solvent W2 + bubble + sample + bubble),
3. Wash the outside of needle 1 with solvents W1 and W2,
4. Thoroughly wash the injection valve 9 and sample loop with solvent W1 and W2 sent from the pump,
5. Injection,
6. Wash syringe 5 with solvent W1,
7. Thoroughly wash syringe 5 with solvents W1 and W2 sent from pumps 27A and B,
8. Thoroughly clean injection valve 9 with solvents W1 and W2 sent from pumps 27A and B.

The carryover rate (%) was calculated as follows.
First, the background chemical noise level was measured (injection # 0), and samples of three different concentrations were injected and analyzed in order of increasing concentration (injections # 1- # 3). Finally, three blanks (injections # 4- # 6) were measured. The carry-over rate (%) was calculated as the ratio of the peak area (B1) of Blank 1 to the peak area (c) of the highest concentration sample. The results are shown in Table 2.

  Next, Table 3 shows a comparison of the analysis results of reserpine, ibuprofen, and chlorhexidine. Ibuprofen is used for performance evaluation in anion mode, and chlorhexidine is known to have a strong tendency to carry over. First, the carryover rates of the conventional needle and the needle of the present invention were compared between reserpine and ibuprofen. For both compounds, carry-over in the needle of the present invention was not substantially detected, but carry-over occurred remarkably in the conventional needle. It should be noted that the chlorhexidine carryover, which is likely to cause carryover, was not detected by the conventional cleaning method. These results show that the AMR cleaning system equipped with the syringe with the needle of the present invention is very effective in eliminating carryover in high sensitivity and high throughput analysis.

Sectional drawing which shows the structure of the needle unit of this invention. Explanatory drawing of the washing | cleaning system of the sample injection apparatus used for this invention. Explanatory drawing which shows the suction state of the sample using the needle unit of this invention. Explanatory drawing of the washing | cleaning system of the conventional sample injection apparatus.

Explanation of symbols

1. Needle unit, 1A. Needle unit for suction, 1B. 1. Liquid distillation needle part 2. barrel Plunger, 5. 6. Sample injection syringe, 8. injection port; Injection valve, 15A, B.I. Cleaning solvent supply means, 40. Switching valve, 41. Side port.

Claims (9)

A needle unit connected to a syringe as a sample suction device directly or via a pipe line, the needle unit having a hole end for sucking a sample; A liquid-retaining needle portion comprising a narrow tube having an inner diameter B larger than an inner diameter A of the thin-tube tube of the suction needle portion that is seamlessly connected to the suction needle portion, and the liquid-retaining needle portion is injected A needle unit for sample injection, which has a capacity sufficient to hold a sample to be retained. The needle unit according to claim 1, wherein the inner diameter A is in a range of 0.15 to 0.45 mm. The needle unit according to claim 1 or 2, wherein the inner diameter B is in a range of 0.15 to 1.0 mm. The suction needle portion of the length _{L 1} is 35.8mm, the inner diameter A is 0.42 mm, the liquid distillate needle portion of the length _{L 2} is 22.5 mm, according to claim 1 the inner diameter B is 0.7mm Needle unit. When a sample is sucked into the sample injection syringe having the needle unit according to any one of claims 1 to 4, each layer of solvent, air, sample, and air is sequentially formed from the opening end of the suction needle portion. A method for sucking a sample of a sample injection syringe, wherein the sample is sucked into the tube and the sample layer is retained in a liquid distillation needle portion below the barrel of the syringe. A sample injection syringe using the needle unit according to claim 1. The sample injection syringe according to claim 6, an injection port into which the sample injection syringe is inserted, an injection valve connected to the injection port, and a plurality of cleaning solvent supplies connected to the injection valve via a pipe line A side port for injecting a cleaning solvent into a barrel side wall of the sample injection syringe, and a cleaning line switching valve is provided in a pipe line between the injection valve and the cleaning solvent supply unit, 7. The sample injection system according to claim 6, wherein pipes for supplying the cleaning solvent to the inner cylinder of the injection port and the side ports provided on the side wall of the barrel are provided through the switching valve. Nji of the cleaning apparatus. The injection port includes an insertion hole into which a sample injection syringe is inserted, an inner cylinder having the insertion hole at the bottom, and an outer cylinder having an upper end higher than the inner cylinder and spaced from the inner cylinder. The cleaning apparatus according to claim 7, further comprising a cleaning liquid discharge port provided at a bottom portion of the outer cylinder. A plurality of cleaning solvents are pumped through the switching valve and injection valve to the injection port, syringe side port, and sample discharge flow path for cleaning, and the cleaning solvent is allowed to overflow the inner cylinder of the injection port. 9. The cleaning method for a cleaning apparatus according to claim 8, wherein the outside of the needle is cleaned by inserting and removing the needle into the solvent of the inner cylinder.

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