JPH11337478A - Measuring method for optical characteristic and polarimeter used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a measuring method in which the removal of a sample cell is not required when a sample to be inspected is replaced, in which the influence of bubbles is suppressed and in which the measuring accuracy of an optical characteristic is enhanced by a constitution, wherein the sample cell which is cylindrical and which is provided with transmitting faces at both ends is arranged in such a way that its axis is tilted. SOLUTION: A step wherein a sample cell 1 which is cylindrical and which is provided with light transmitting faces at both ends when the angle of rotation or the like of a liquid sample is measured, a step in which the sample is introduced into the cell 1 and a step in which light is projected comprise a measuring method for an optical characteristic. For example, a cell 1 which is provided with a coil 5 used to apply a magnetic field is arranged on a tilted rail 10, a sample such as a urine sample or the like is introduced from a sample introduction and discharge port in the lower end part of the cell 1, and the air is discharged from a vent in the upper end part. Prescribed parallel light from a projection optical module 11 is incident on an optical sensor 14 via a polarizer 12, the cell 1 and an analyzer 13, the current of the coil 5 is controlled by its output signal, and the angle of rotation of the sample is found. Since the cell 1 is tilted, it is possible to prevent the disturbance of bubbles to projected light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the optical characteristics of a liquid test sample, and more particularly to a method of arranging a sample cell for holding a test sample and a test sample therefor. The present invention relates to an improvement of an infusion method of the invention.

[0002]

2. Description of the Related Art Conventionally, measurement of optical properties such as optical rotation, light transmittance and light reflectance of a liquid sample has been carried out by identifying the solute,
It is applied to purity test, concentration determination, etc. For example, the measurement of optical rotation is widely used for determining the concentration of fructose, sucrose, glucose and the like in an aqueous solution. In recent years, urinary sugar levels (glucose levels) and urine protein levels (albumin levels)
It has also been proposed to apply it to the determination of international publication number (International Publication Number WO9
7/18470). According to the same publication, glucose and albumin in urine show optical rotation, while other urine components do not show optical rotation.Therefore, it is necessary to determine the concentration of these by measuring the optical rotation of urine. It can be done.

[0003] In general, when measuring the optical characteristics of a test sample, not only in a urine test, the sample is introduced into a sample cell configured to allow light to pass therethrough, and light is projected on the sample. The sample cell is made of, for example, glass,
It has a pair of transparent transmitting surfaces for transmitting light inside. Conventionally, the sample cell has a box shape with an open top,
The liquid test sample was introduced from this opening using a dropper, pipettor, syringe, or the like. The measurement was performed for each sample cell, and the replacement of the test sample was also performed for each sample cell. That is, after introducing the test sample into the sample cell, the sample cell is arranged in the optical system, and the optical characteristics of the test sample are measured. Therefore, the test sample had to be replaced together with the sample cell, and in order to reuse the sample cell, it was necessary to discharge the test sample from the sample cell removed from the optical system and to wash the sample cell. . As described above, the conventional measurement of the optical characteristics is very troublesome. Further, when the sample is dropped into the sample cell, bubbles are easily generated. Therefore, there is also a problem that bubbles are interposed in the optical path during the measurement, and the measurement accuracy is likely to be reduced.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method for measuring optical characteristics in which a test sample can be easily exchanged. It is another object of the present invention to provide a method for measuring optical characteristics with high accuracy, which can prevent bubbles from being mixed into a test sample.

[0005]

In the present invention, a cylindrical sample cell having transmission surfaces at both ends is used as a sample cell for holding a test sample whose optical characteristics are to be measured. The sample cell is disposed with its axis inclined, and the traveling direction of light projected on the sample cell is also inclined.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the optical characteristic measuring method of the present invention, in measuring optical characteristics of a liquid sample, a sample cell having a cylindrical hollow portion and a pair of end surfaces of the hollow portion each having a transmitting surface through which light is transmitted. And a step of introducing a sample to be measured into the hollow portion, and projecting light onto the transmission surface along the axis of the hollow portion. In the present invention, a substantially closed cylindrical sample cell is used in place of the conventional box-shaped open sample cell, and the axis thereof is further inclined. By using such an inclined cylindrical sample cell,
Bubbles generated during the introduction of the sample can be moved to the upper end of the hollow portion. Therefore, the bubble can be effectively moved to a position deviated from the optical path of the measurement light, and highly accurate measurement can be performed. In introducing the sample into the sample cell as described above, the lower end and the upper end of the hollow portion arranged with the axis inclined are provided with holes that respectively communicate with the outside,
A sample is introduced into the hollow part through the hole at the lower end. This makes it difficult for bubbles to be generated during the introduction of the sample, and allows the bubbles generated during the introduction to be more effectively moved to the upper end.

The polarimeter of the present invention has a sample cell for holding a test sample whose optical characteristics are to be measured, sample supply means for supplying the test sample to the sample cell, and projects substantially parallel light to the sample cell. A monochromatic light source, a polarizer disposed in front of the sample cell and transmitting only a polarized light component in a specific direction out of the substantially parallel light, and a coil for applying a magnetic field to the test sample in the sample cell in a propagation direction of the substantially parallel light A current source for supplying a current to the coil; a magnetic field sweeping means for sweeping the current to sweep the magnetic field; a magnetic field modulation means for modulating the current to oscillate the magnetic field; An analyzer that transmits only polarized light components in a specific direction out of the light that has passed through the test sample, an optical sensor that detects light that has passed through the analyzer, and an output signal of the optical sensor that is a reference signal that is a vibration modulation signal of the magnetic field modulation unit. As phase sensitive A lock-in amplifier that oscillates, and an arithmetic unit that calculates the optical rotation of the test sample based on a magnetic field sweep signal of the magnetic field sweep unit and an output signal of the lock-in amplifier, wherein the sample cell has a cylindrical hollow portion and a hollow portion. Are provided with transmission surfaces for transmitting light, respectively, and are arranged with the axis of the hollow portion inclined. By inclining the sample cell as described above and further inclining the light projection direction, the influence of bubbles on the measurement accuracy can be reduced. Among the optical characteristics, in the measurement of the optical rotation, if the above-described polarimeter is used, other polarimeters, for example, project light polarized in a specific direction onto the sample, and determine the angle of rotation of the transmitted light by a rotation analyzer. A higher accuracy can be obtained as compared with a polarimeter which directly obtains the optical rotation by using the optical system.

The method for measuring optical characteristics as described above can be applied to urinalysis. Examples of the optical rotation substance contained in urine include glucose, albumin, L-ascorbic acid and amino acids. Of these,
In particular, the glucose concentration (protein value) and the glucose concentration (urine sugar value) of urine can be measured with high accuracy. When used as a urinalysis device, it is less susceptible to bubbles and is highly practical due to its high reliability, small size and low cost.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a preferred embodiment of the present invention, measurement of optical rotation will be described in detail with reference to the drawings. In this embodiment, a magnetic field is generated in the sample to compensate for the optical rotation caused by the optically rotating substance in the sample, and the optical rotation is calculated from the magnitude of the magnetic field. Light rotates when passing through a magnetic field. At this time, the angle of optical rotation is proportional to the magnitude of the magnetic field. Also,
As described above, when light passes through the liquid sample containing the optical rotatory substance, the optical rotation is performed in proportion to the concentration of the optical rotatory substance. Therefore, the polarimeter of the present embodiment obtains the optical rotation of the sample from the strength of the magnetic field when the extinction point appears, and further obtains the concentration of the optical rotation substance in the sample.

The sample cell 1 shown in FIG. 1 is obtained as follows. First, the cross section is 25mm on a side
Was cut into a cylindrical shape having a diameter of 12 mm by cutting a side surface of an aluminum block having a length of 55 mm and a length of 55 mm at each end. Further, a hole is made by penetrating between a pair of end faces in the length direction, and a diameter of 1 mm is formed.
A 0 mm cylindrical hollow portion 2 was formed. Next, circular holes having a depth of 2.5 mm and a diameter of 12 mm are respectively formed in the openings of the hollow portion 2, and a circular glass plate having a thickness of 2.5 mm and a diameter of 12 mm is formed in these holes. 3 and 4 were fitted. The hollow portion 2 has a volume of about 2.5 cc and an axial length, that is, an optical path length of 50 mm. A 0.7 mm diameter is formed on the cylindrical outer surface of the sample cell 1.
The enameled wire was wound 600 times to form a coil 5 for applying a magnetic field to the test sample accommodated in the hollow portion 2.
In the vicinity of one end of the hollow portion 2 of the sample cell 1, an inlet / outlet 6 having a diameter of 1.0 mm was formed so as to communicate with the outer surface.
Also, on the other end side of the hollow portion 2, the inlet / outlet 6
A vent hole 7 having a diameter of 2.5 mm and communicating with the outer surface was formed at a location rotated 180 degrees from the location where was disposed.

The sample cell 1 is used, for example, as follows. As shown in FIG. 2, the sample cell 1 is placed on a rail 10 inclined at, for example, 45 degrees. The projection module 11 uses a semiconductor laser as a light source and emits substantially parallel light having a wavelength of 670 nm and an intensity of 5 mW to the sample cell 1.
Project toward. The light projected by the projection module 11 travels in the direction of the arrow in the figure and is detected by the optical sensor 14. Upstream of the sample cell 1, a polarizer 1 that transmits only a specific polarization component of the projection light of the projection module 11
2 are arranged. Downstream of the sample cell 1, an analyzer 13 that transmits light that is projected from the projection module 11 and transmitted through the sample cell 1 is arranged. Analyzer 13
Are arranged in a state of orthogonal Nicols with respect to the polarizer 12.

The computer 16 issues a command signal to the current source 17 to sweep the current flowing through the coil 5 in the range of -5 to 5A. The signal generator 18 supplies a 1.3 kHz vibration modulation signal to the current source 17. The current source 17 converts the vibration modulation signal from the signal generator 18 into a vibration modulation current signal having an amplitude of 0.02 A, and superimposes the vibration modulation current signal on the sweep current instructed by the computer 16, and then supplies this to the coil 5. The lock-in amplifier 15 performs phase-sensitive detection of the output signal of the optical sensor 14 using the vibration modulation signal of the signal generator 18 as a reference signal. Since the output signal of the lock-in amplifier 15 corresponds to the angular frequency component of the output signal of the optical sensor 14, the time when the output signal of the lock-in amplifier 15 becomes zero is the extinction point.

Here, the sample cell 1 has an inlet / outlet 6
Are located at the lower end, and the ventilation holes 7 are located at the upper end. The sample is introduced into the sample cell 1 through the introduction / exhaust port 6 using a syringe, a pump, or the like. At this time, since the air in the hollow portion 2 is exhausted from the vent 7, the liquid sample can be smoothly introduced. Here, the hollow portion 2
Since the axis is inclined, bubbles are less likely to be generated during sample introduction. Furthermore, even if bubbles are generated, the bubbles move above the sample, and then move along the upper surface of the hollow portion 2 toward the upper end of the hollow portion 2 having the ventilation port 7, so that the bubbles are projected light. Can be prevented.

When the measurement is completed and the sample is to be replaced, the sample in the hollow portion 2 is discharged from the inlet / outlet 6. When the amount of the sample to be measured is larger than the volume of the hollow portion 2, a new sample is introduced into the inlet / outlet 6 while the sample whose measurement has been completed remains in the hollow portion 2. The sample that has been introduced and the measurement of which has been completed may be discharged from the vent 7 and replaced. When the sample cell 1 is washed, a washing solution or water is similarly introduced into the hollow portion 2 from the inlet / outlet 6. Here, by continuously supplying a large amount of cleaning liquid and the like to the hollow portion 2 and discharging the same through the ventilation port 7,
The sample cell 1 can be effectively cleaned. In addition, although the light is projected toward the sample cell 1 upward from the oblique lower side, the light may be projected downward from the oblique upper side.

Regarding suppression of foaming of the sample, for example, as shown in FIG. 3, the axis of the hollow portion 22 is inclined, and light is emitted in the horizontal direction in the sample cell 21 provided with the inlet / outlet 26 and the vent 27. Similar effects can be obtained when measuring by projection. However, this method has the following problems. The measurement optical path length has a great influence on the measurement accuracy of the optical characteristics. In order to prevent the projection light from being refracted when entering the sample, the light traveling direction needs to be perpendicular to the transmission surfaces 23 and 24, so that the axis of the hollow portion 22 of the sample cell 21 is inclined. In order to ensure the same optical path length as the sample cell 1 used in this embodiment, the length of the hollow portion 22 needs to be longer. Further, in order to incline the axis of the hollow portion 22 at a high angle, it is necessary to increase the diameter of the hollow portion 22. Therefore, the volume of the hollow portion needs to be larger than that of the sample cell 1 in the present embodiment, and a large amount of sample is required for measurement.

The process of inclining the normal direction of the transmission surface of the sample cell from the axial direction of the hollow portion is inefficient and increases the cost of the sample cell. In addition, since the sample has an acute peak, solids in the sample tend to adhere and remain. When applying a magnetic field to the sample to be tested by the coil 25 in the same manner as the sample cell 1 of the embodiment,
Since the diameter and the length of the hollow portion 22 become large, if an attempt is made to form a magnetic field equivalent to that of the sample cell 1, the coil 25
Or the amount of current supplied to the coil 25 needs to be increased. Increasing the number of turns of the coil increases the amount of heat generated by the coil. Also, even if the amount of current supplied to the coil is increased, the amount of heat generated by the coil also increases. As described above, when the amount of heat generated by the coil increases, measurement accuracy deteriorates. That is, such measurement is inferior to the measurement method of the present invention in accuracy, cost, and the like.

[0017]

According to the present invention, it is not necessary to remove the sample cell for exchanging the sample in the measurement of the optical characteristics, so that the measurement with high workability can be performed. In addition, it is possible to suppress the influence of bubbles generated at the time of introducing the sample on the measurement accuracy, so that highly accurate measurement can be performed. further,
The amount of sample required for measurement can be reduced. Further, according to the present invention, it is possible to accurately test the concentration of glucose and protein, which are optical rotation substances in urine,
It is possible to provide a small, inexpensive urinalysis device with high reliability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the structure of a sample cell used in a polarimeter according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a homorotometer.

FIG. 3 is a longitudinal sectional view showing a structure of a sample cell of a comparative example.

[Explanation of symbols]

 1,21 sample cell 2,22 hollow part 3,4 glass plate 5,25 coil 6,26 inlet / outlet port 7,27 vent port 11 projection module 12 polarizer 13 analyzer 14 optical sensor 15 lock-in amplifier 16 computer 17 current Source 18 Signal generator 23, 24 Transmission surface

Claims (6)

[Claims] 1. A method for measuring optical properties of a liquid sample, comprising: a sample cell having a cylindrical hollow portion and a pair of end surfaces of the hollow portion each having a light transmitting surface for transmitting light;
Arranging the axis of the hollow portion at an angle, introducing a liquid sample to be measured into the hollow portion, and projecting light onto the transmission surface along the axis of the hollow portion. Optical property measurement method. 2. The optical characteristic according to claim 1, wherein the sample cell has holes communicating with the outside at the lower end and the upper end of the hollow portion, respectively, and the sample is introduced into the hollow portion through the hole at the lower end. Measuring method. 3. The optical characteristic measuring method according to claim 2, wherein the sample cell is arranged so that the light at the lower end portion is on the upstream side and the hole at the upper end portion is on the downstream side. 4. A sample cell for holding a test sample whose optical characteristics are to be measured, sample supply means for supplying the test sample to the sample cell, and a monochromatic light source for projecting substantially parallel light to the sample cell. And a polarizer disposed in front of the sample cell and transmitting only a polarization component in a specific direction of the substantially parallel light, and applying a magnetic field to a test sample in the sample cell in a propagation direction of the substantially parallel light. Coil, a current source that supplies a current to the coil, a magnetic field sweeping unit that sweeps the current to sweep a magnetic field, a magnetic field modulation unit that modulates the current to vibrate the magnetic field, and the sample cell An analyzer that is disposed at a subsequent stage and transmits only a polarized light component in a specific direction out of the light transmitted through the test sample, an optical sensor that detects light transmitted through the analyzer, and an output signal of the optical sensor. The magnetic field A lock-in amplifier that performs phase-sensitive detection using a vibration modulation signal of a modulation unit as a reference signal, and a calculation unit that calculates an optical rotation of the test sample based on a magnetic field sweep signal of the magnetic field sweep unit and an output signal of the lock-in amplifier. A polarimeter, wherein the sample cell includes a cylindrical hollow portion and a pair of end surfaces of the hollow portion that transmit light, and is arranged with the axis of the hollow portion inclined. 5. The polarimeter according to claim 4, wherein the test sample is urine, and the concentration of the optical rotation substance contained in the urine is determined from the obtained optical rotation. 6. The polarimeter according to claim 5, wherein the optical rotation substance is at least one of glucose and albumin.