JP6600842B2 - Optical rotation and refractive index measuring device - Google Patents

Description

  The present invention relates to an optical rotation and refractive index measuring apparatus capable of measuring the optical rotation and refractive index of a liquid or solid under the same conditions.

  Conventionally, a method of measuring the refractive index of a measurement object and converting the measured refractive index into a concentration (Brix value) is known. On the other hand, Patent Document 1, Patent Document 2, and Non-Patent Document 1 describe a method of measuring the optical rotation of a measurement object by rotating a polarizing element.

  For example, in order to calculate the pure sugar ratio that represents the ratio of the amount of sucrose contained in the total soluble solid content, two parameters are required: the Brix value obtained from the refractive index and the optical rotation obtained from the polarimeter. It is.

  That is, it is necessary to obtain the third parameter from the binary value of the optical rotation and the Brix value.

JP 2005-292028 A JP 2009-085853 A

Wakayama Toshitaka, Tsushima Hideki, Nakajima Yoshinori, Otani Yukitoshi, Umeda Michihiro: “Liquid Crystal Polarimeter”, Proceedings of the Japan Society of Applied Physics, 1137 (2005).

  By the way, the refractive index and the optical rotation of the object to be measured are measured by dedicated measuring machines. Therefore, in order to obtain the third parameter from these two values, the measurement value obtained by one measuring machine must be calculated by inputting it to the other measuring machine, which is complicated.

  Moreover, it is not possible to measure each value at the same time while keeping the measurement object under the same measurement conditions.

  Furthermore, the conventional polarimeter for measuring the optical rotation is large because it is configured using a drive mechanism such as a motor, and it is difficult to configure it as a small and easy-to-measure instrument.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and the optical rotation and refractive index of the measurement object can be simultaneously measured under the same measurement conditions, and the measurement operation is simple. And it aims at providing the measuring device of the optical rotation and refractive index which is easy to comprise as a small apparatus.

  In order to solve the above-described problems and achieve the above object, an optical rotation and refractive index measurement device according to the present invention has the following configuration.

[Configuration 1]
Measures information corresponding to the refractive index of the measurement object accommodated in the sample chamber, the optical rotation measurement unit for measuring the optical rotation of the measurement object accommodated in the sample chamber, and the measurement object accommodated in the sample chamber And the sample chamber transmits the analysis target light incident from the outside of one side through the measurement target object stored therein, and transmits the analysis target light transmitted through the measurement target side to the other side. And a part of the wall or bottom of the space for accommodating the measurement object is constituted by one surface of the prism, and the optical rotation measurement unit A light source that emits light, a polarization modulation unit that modulates polarization of the analysis target light and enters the sample chamber, an intensity detection unit that detects the light intensity of the analysis target light that has passed through the sample chamber, and the intensity detection unit Based on the light intensity information, An optical rotation calculation unit that calculates characteristic elements and calculates the optical rotation of the measurement object, and the refractive index measurement unit emits the analysis target light and makes it incident on a prism that forms part of the wall or bottom of the sample chamber A position detection unit that detects position information of light to be analyzed that is emitted from the prism through one surface of the prism that is incident on the prism and forms part of the wall or bottom of the sample chamber, and is detected by the position detection unit. And a refractive index (concentration) calculating section for calculating a refractive index or a density based on position information corresponding to the refractive index of the measured object.

[Configuration 2]
In the optical rotation and refractive index measurement device having configuration 1, the third optical rotation is calculated based on the optical rotation calculated by the optical rotation calculation unit and the refractive index or concentration calculated by the refractive index (concentration) calculation unit. The parameter is calculated.

[Configuration 3]
In the optical rotation and refractive index measurement device having the configuration 2, the refractive index (concentration) calculation unit calculates a Brix value, and the third parameter is a pure sugar rate of the measurement object. is there.

  In the optical rotation and refractive index measurement device according to the present invention, by having one sample chamber, an optical rotation measurement unit, and a refractive index measurement unit, binary measurement can be performed simultaneously under the same conditions. Measurement time can be shortened. That is, by simultaneously measuring information corresponding to the optical rotation and the refractive index, it is possible to save time and effort to input one parameter to another measuring device.

  Therefore, the optical rotation and refractive index measurement device according to the present invention is useful when the third parameter is derived from two parameters, such as the pure sugar rate.

  Furthermore, the optical rotation and refractive index measuring device according to the present invention can be miniaturized and can be easily measured.

  That is, the conventional optical rotation measuring device is a device in which the polarizing element is rotated by a motor, or a large and complicated polarization modulator such as a Faraday cell or PEM is used. It is difficult to make a device integrated with a small refractive index measuring device.

  On the other hand, in the optical rotation and refractive index measurement device according to the present invention, if a liquid crystal element is used as the polarization modulation unit, the driving unit such as a motor can be eliminated and the size can be reduced. The liquid crystal element is also driven at low voltage and low power consumption. As a result, it is possible to integrate with an existing small-sized refractive index measuring device to obtain an optical rotation and refractive index measuring device.

  Conventionally, an observation tube with a fixed optical path length is used for measuring the optical rotation of a liquid sample. When the observation tube is used, a mechanism for setting the observation tube is required, and there is a restriction on downsizing the apparatus. Further, when the refractive index is to be measured simultaneously, it is necessary to attach a refractive index detector to the observation tube, which complicates the structure.

  On the other hand, in the optical rotation and refractive index measuring apparatus according to the present invention, the configuration of the sample chamber is such that the analysis target light incident from the outside on one side is emitted to the outside on the other side. The use of a pipe is unnecessary, and the apparatus can be simplified and downsized.

  In other words, the present invention can simultaneously measure information corresponding to the optical rotation and refractive index of a measurement object under the same measurement conditions, and can be configured as a compact device with a simple measurement operation. It is possible to provide an apparatus for measuring optical rotation and refractive index that is easy.

It is a block diagram which shows the structure of the measuring device of the optical rotation and refractive index which concerns on this invention.

[Outline of Configuration of Measuring Device for Optical Rotation and Refractive Index According to the Present Invention]
FIG. 1 is a block diagram showing the configuration of an optical rotation and refractive index measuring apparatus according to the present invention.

  As shown in FIG. 1, the optical rotation and refractive index measurement device according to the present invention calculates the optical rotation of the sample chamber 1 in which the measurement object 101 is accommodated and the measurement object 101 accommodated in the sample chamber 1. The optical rotation measuring unit 2 for measuring and the refractive index measuring unit 3 for measuring information corresponding to the refractive index of the measuring object 101 accommodated in the sample chamber 1 are configured.

  The sample chamber 1 can directly inject the measurement object 101, and the analysis object light 4 incident from the outside of one side is transmitted through the measurement object 101 accommodated therein and transmitted through the measurement object 101. The analysis target light 5 is configured to be emitted to the outside on the other side. That is, an incident window 6 is formed on one side of the sample chamber 1. The entrance window 6 is configured by closing an opening on one side of the sample chamber 1 with a transparent material. An exit window 7 is formed on the other side of the sample chamber 1. The exit window 7 is configured by closing the opening on the other side of the sample chamber 1 with a transparent material. The transparent material forming the entrance window 6 and the exit window 7 is made of a material that does not change the optical rotation state of the transmitted light beam or a material whose change is known in the optical rotation state given to the transmitted light beam.

  Further, in the sample chamber 1, a part of the wall portion or the bottom portion of the space that accommodates the measurement object 101 is configured by one surface 8 a of the prism 8 that constitutes the refractive index measurement unit 3. In this embodiment, one surface 8 a of the prism 8 forms a part of the bottom of the space that accommodates the measurement object 101 in the sample chamber 1.

  The optical rotation measuring unit 2 includes a light source 10 that emits the analysis target light 9 and a polarization modulation unit 11 that modulates the polarization of the analysis target light 9 and enters the sample chamber 1 from the incident window 6. As the light source 10, for example, a monochromatic LED can be used. The analysis target light 9 emitted from the light source 10 is converted into a parallel light beam by the condenser lens 14.

  The polarization modulation unit 11 includes a polarizer 15 that transmits only a predetermined polarization component, and first and second liquid crystal elements 16 and 17. The applied voltages of the liquid crystal elements 16 and 17 are controlled by the control signal generator 18. Further, the temperature of the liquid crystal elements 16 and 17 is detected by the temperature sensor 19, and the temperature information is sent to the control signal generator 18. The control signal generator 18 controls the liquid crystal elements 16 and 17 to a predetermined optical rotation state based on the temperature information sent from the temperature sensor 19. Alternatively, it may be calculated by correcting the optical rotation based on the temperature information sent from the temperature sensor 19 of the liquid crystal elements 16 and 17 without controlling the voltage applied to the liquid crystal elements 16 and 17.

  The optical rotation measurement unit 2 includes an intensity detection unit 12 that detects the light intensity of the analysis target light 5 emitted from the emission window 7 through the sample chamber 1. In this optical rotation and refractive index measurement device, the light intensity of the analysis target light 5 emitted from the emission window 7 changes according to the optical rotation of the measurement object 101 in the sample chamber 1.

  The intensity detection unit 12 includes an analyzer 20 and a light receiving sensor (photosensor) 21. The analysis target light 5 emitted from the emission window 7 is received by the light receiving sensor 21 through the analyzer 20. The light intensity information detected by the intensity detector 12 is sent to the optical rotation calculator 13. Further, the temperature of the sample chamber 1 is detected by the temperature sensor 22, and the temperature information is sent to the optical rotation calculator 13.

  The optical rotation calculation unit 13 calculates the polarization characteristic element of the analysis target light 5 based on the light intensity information sent from the intensity detection unit 12 and the temperature information sent from the temperature sensor 22, and the optical rotation of the measurement target 101. Calculate the degree. The calculation result in the optical rotation calculation unit 13 is stored in the storage unit 23.

  The optical rotation calculation unit 13 is configured as one calculation unit 13 together with a refractive index (concentration) calculation unit described later.

  The refractive index measurement unit 3 includes a light source 25 that emits the analysis target light 24 and causes the analysis target light 24 to enter the prism 8. The light source 25 is, for example, a monochromatic LED, is a point light source, and emits analysis target light 24 that is diffused light.

  The analysis target light 24 incident on the prism 8 is incident on one surface 8a of the prism 8 forming a part of the bottom of the sample chamber 1, and is internally reflected by the surface 8a and emitted from the other surface of the prism 8. The The analysis target light 24 emitted from the prism 8 enters the position detection unit 26. The position detection unit 26 is, for example, a CCD, and detects the emission position of the analysis target light 24 that is internally reflected by one surface 8 a of the prism 8.

  In this optical rotation and refractive index measurement device, the emission position of the analysis target light 24 that is internally reflected by one surface 8 a of the prism 8 changes according to the refractive index of the measurement target 101 in the sample chamber 1. This is because one surface 8 a of the prism 8 is an interface between the prism 8 and the measurement object 101, and the critical angle on the surface 8 a is determined by the refractive index of the measurement object 101. The position information of the analysis target light 24 is information corresponding to the refractive index of the measurement target 101.

  Note that a parallel light beam may be used as the analysis target light in the refractive index measurement unit 3. In this case, the analysis object is transmitted through the measurement object 101, transmitted through one surface 8a of the prism 8 (interface between the prism 8 and the measurement object 101), and emitted from the other surface of the prism 8. Light position information is detected. The position information detected in this way is also information corresponding to the refractive index of the measurement object 101.

  The position information detected by the position detector 26 is sent to the refractive index (density) calculator 13. In this embodiment, the refractive index (concentration) calculator 13 calculates the Brix value of the measurement object 101 based on the positional information of the transmitted analysis target light 24. The Brix value may be calculated directly from the position information of the analysis target light 24, or the refractive index of the measurement object 101 may be calculated from the position information and converted to the Brix value from this refractive index. In any calculation method, the Brix value is calculated based on the position information corresponding to the refractive index of the measurement object 101.

  In the calculation of the Brix value, correction is performed based on the temperature information (the temperature of the measurement object 101) sent from the temperature sensor 22 in the sample chamber 1.

  In the optical rotation and refractive index measurement device, the third parameter is calculated based on the optical rotation calculated by the optical rotation calculation unit 13 and the Brix value calculated by the refractive index (concentration) calculation unit 13. Calculations can be made. This third parameter is, for example, the pure sugar rate of the measurement object 101.

[Specific Configuration Example of Optical Rotation and Refractive Index Measuring Device According to the Present Invention]
As the light source 10 of the optical rotation measuring unit 2, a monochromatic LED having an emission wavelength near 590 nm was used. The analysis target light 9 passing through a pin hole of φ0.4 mm is converted into a parallel light beam by a biconvex lens 14 having a focal length of 9 mm, and a polarization modulator 11 constituted by a polarizer 15 and two liquid crystal cells 16 and 17, Polarization modulation was performed. The orientations of the polarizer 15 and the two liquid crystal cells 16 and 17 were set to 0 °, 45 °, and 0 °, respectively. The liquid crystal cells 16 and 17 were driven by an AC voltage from the signal generator 18. For the liquid crystal cells 16 and 17, nematic liquid crystal having Δn of 0.2 and cell gap of 5.5 μm was used.

  The analysis target light 4 that has been polarization-modulated by the polarization modulator 11 is rotated by passing through the measurement object 101 in the sample chamber 1. An entrance window 6 and an exit window 7 are attached to the left and right side surfaces of the sample chamber 1 so that the analysis target light 4 is transmitted through the sample chamber 1. BK-7 was adopted as a transparent material forming the entrance window 6 and the exit window 7. The distance from the entrance window 6 to the exit window 7 was set to 20 mm. The analysis target light 5 that has passed through the measurement object 101 passes through the analyzer 20 having an azimuth of 90 ° and is detected by the light receiving sensor 21. Since the optical rotation measurement method in the optical rotation measurement unit 2 is a well-known method, detailed description thereof is omitted.

  The light source 25 of the refractive index measuring unit 3 is also a monochromatic LED having an emission wavelength near 590 nm. The analysis target light 24 emitted as a point light source diffuses in the prism 8 and is reflected on one surface 8a of the prism 8 which forms a part of the bottom of the space for accommodating the measurement target 101 in the sample chamber 1, or To Penetrate. The reflected analysis target light 24 is emitted from the other surface of the prism 8, and position information is detected by the position detection unit 26. The position information detected by the position detector 26 is due to the occurrence of light and darkness at a critical angle that is the boundary between reflection and transmission on one surface 8a of the prism 8, and corresponds to the refractive index of the measurement object 101. Information. A CCD line sensor was used for the position detection unit 26. Moreover, SF-2 was used as a material forming the prism 8.

[Measurement Example of Pure Sugar Ratio in Optical Rotation and Refractive Index Measuring Device According to the Present Invention]
The pure sugar rate is defined by the following formula.
Pure sugar rate [%] = (sucrose amount / total soluble solids) × 100

  The total soluble solid content is represented by the Brix value [%].

The amount of sucrose is defined as follows.
Sucrose amount = (mass (density) of liquid of 26.016 / 100 ml) × international sugar content

  In addition, the mass of 100 ml of liquid is calculated | required from the 4th term | formula (2) of SPS-4 of ICUMSA. The international sugar content is the value obtained by setting the optical rotation when measuring a 26.000 g / 100 ml sucrose solution with a 200 mm observation tube to 100 ° Z, as described in Section 3.2 of ICUMSA SPS-1. Is defined. (ICUMSA Japan Subcommittee: ICUMSA Methods Book, SPS-1 (2005) pp.1-7. ICUMSA Japan Subcommittee: ICUMSA Methods Book, SPS-4 (1994) pp. [71] 1- [71] 11.)

From these relationships, the pure sugar ratio was calculated using the measured optical rotation and Brix value. Table 1 below shows the results of measurement for three types of sucrose 10% (w / w), 20% (w / w), and 30% (w / w).

  Since there was no mixture, the pure sugar ratio was almost 100% for all three types of samples.

  The present invention is applied to an optical rotation and refractive index measuring apparatus capable of measuring the optical rotation and refractive index of a liquid or solid under the same conditions.

DESCRIPTION OF SYMBOLS 1 Sample chamber 2 Optical rotation measuring part 3 Refractive index measuring part 4, 5, 9, 24 Analysis object light 8 Prism 8a One surface 10, 25 Light source 11 Polarization modulation part 12 Intensity detection part 13 Optical rotation calculating part, Refractive index ( (Concentration) calculation unit 26 position detection unit 101 measurement object

Claims (6)

A sample chamber in which an object to be measured is stored;
An optical rotation measurement unit for measuring the optical rotation of the measurement object accommodated in the sample chamber;
A refractive index measuring unit that measures information corresponding to the refractive index of the measurement object accommodated in the sample chamber,
The sample chamber is configured to transmit the analysis target light incident from the outside on one side through the inside of the measurement target accommodated and to emit the analysis target light transmitted through the measurement target to the outside on the other side. And part of the wall or bottom of the space for accommodating the measurement object is constituted by one surface of the prism,
The optical rotation measuring unit includes a light source that emits analysis target light, a polarization modulation unit that modulates the polarization of the analysis target light and enters the sample chamber, and an intensity for detecting light intensity of the analysis target light that has passed through the sample chamber. A detector, and an optical rotation calculator that calculates a polarization characteristic element of the light to be analyzed based on the light intensity information detected by the intensity detector and calculates the optical rotation of the measurement object,
The refractive index measuring unit emits light to be analyzed and enters a prism that forms part of the wall or bottom of the sample chamber, and the light source that enters the prism and forms part of the wall or bottom of the sample chamber. A position detector that detects position information of the light to be analyzed emitted from the prism via one surface of the prism, and refracted based on position information corresponding to the refractive index of the measurement object detected by the position detector. A refractive index (concentration) calculation unit for calculating a ratio or a concentration,
The polarization modulator includes a liquid crystal element,
The analysis target light in the sample chamber is parallel light, and the optical path of the analysis target light is an optical rotation and refractive index measurement device that is parallel to the one surface of the prism .   From the light source of the refractive index measuring unit, the analysis target light incident on one surface of the prism is divergent light,
  The light source of the optical rotation measurement unit and the light source of the refractive index measurement unit each have independent LEDs.
The optical rotation and refractive index measuring device according to claim 1. 3. The optical rotation and refractive index measurement device according to claim 1, wherein a temperature sensor for measuring the temperature of the liquid crystal element is attached to the liquid crystal element. The prism forms a part of the bottom of the sample chamber, and the sample chamber has only a bottom and a side so that a measurement object can be directly injected.
The optical rotation and refractive index measuring device according to any one of claims 1 to 3. The sample chamber has only a bottom portion and a side portion so that a measurement object can be directly injected, and an upper portion facing the bottom portion is opened to the outside during measurement.
The optical rotation and refractive index measuring device according to any one of claims 1 to 4. 6. The optical rotation and refractive index measurement apparatus according to claim 1, wherein a length of the sample chamber in the optical path direction of the analysis target light is longer than a length in a vertical direction of a side portion of the sample chamber.

Images