JP2013033035A - Optical measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical measuring device enabling fluorescence measurement even in the case of a minute amount of sample solution, and enabling more accurate measurement.SOLUTION: An optical measuring device 1 comprises: a light source part 2; an excitation light transmission part 3; a fluorescence transmission part 4; a sample holding part 5 including a sample holding surface 5a for holding a sample solution; and a light detection part 6 for detecting a frequency component of fluorescence emitted from the sample solution. The excitation light transmission part 3 includes an excitation light transmission fiber 30 that allows excitation light to enter an excitation-light incident side end face 30a, transmits the light and exposes the sample solution to the light from an excitation-light emission side end face 30b. The fluorescence transmission part 4 includes a fluorescence transmission fiber 40 that allows fluorescence emitted by the sample solution to enter a fluorescence incident side end face 40a, transmits the fluorescence and emits the fluorescence to the light detection part 6 from a fluorescence emission side end face 40b. The sample holding surface 5a is formed by uniformly arranging the excitation-light emission side end face 30b and the fluorescence incident side end face 40a.

Description

  The present invention relates to an optical measurement device used for fluorescence measurement of a sample solution.

  Conventionally, in order to examine the component and concentration of a sample solution, measurement is performed by irradiating the sample solution with light (excitation light) from the light source unit, transmitting fluorescence emitted from the sample solution, and detecting the frequency component. Such an optical measuring device is used. In measurement, fluorescence measurement is widely performed by injecting a required amount of sample solution into a sample cell (cuvette) for sample holding.

  On the other hand, the applicant of the present application has proposed an optical measurement apparatus in Patent Document 1 that does not require a sample cell and enables fluorescence measurement even if the amount of the sample solution is very small. This optical measurement apparatus includes a sample holder having a columnar base member and a guide member, and the light incident surface (fluorescence incident side end surface) of the optical fiber transmitting fluorescence is located on the upper end surface of the base member. The guide member is mounted across the light incident surface. This optical measurement apparatus can quickly perform accurate fluorescence measurement by appropriately holding the sample solution dropped by the pipette in the space formed by the upper end surface of the base member and the guide member.

JP 2011-22065 A

  By the way, in the conventional optical measuring apparatus, the excitation light from the light source part passes through the air and irradiates the sample solution, and the fluorescence emitted from the sample solution is emitted in a direction substantially perpendicular to the direction of the excitation light irradiation. Is generally detected and measured.

  However, since the excitation light is reflected or scattered at the interface between the sample solution and its external environment, a part of the excitation light is mixed with fluorescence as a background and measured. Therefore, the background measurement is usually performed in advance by irradiating the excitation light to the aqueous solution (solution containing only the diluting solvent), and the background measurement result is subtracted from the measurement result of the sample solution. Background processing to be removed is performed. Therefore, if the intensity of the background is small after the background processing, an accurate measurement result of the sample solution can be obtained.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide an optical measurement apparatus capable of performing fluorescence measurement even with a small amount of sample solution and capable of performing more accurate measurement. There is.

  In order to achieve the above object, an optical measurement apparatus according to claim 1 includes a light source unit that emits excitation light that irradiates a sample solution, an excitation light transmission unit that transmits excitation light, and a fluorescence transmission unit that transmits fluorescence. And a sample holding unit having a sample holding surface for holding the sample solution, and a light detection unit for detecting a frequency component of fluorescence emitted from the sample solution, wherein the excitation light transmission unit includes the excitation light transmission unit. It has an excitation light transmission fiber that makes light incident on the excitation light incident side end surface, transmits the light and irradiates the sample solution from the excitation light emission side end surface, and the fluorescence transmission unit emits fluorescence emitted from the sample solution. A fluorescence transmission fiber that is incident on the fluorescence incident side end surface, transmits the light, and radiates from the fluorescence emission side end surface to the light detection unit, and the sample holding surface includes the excitation light emission side end surface and the fluorescence incident side End faces are aligned Made is characterized in that is.

  The optical measurement device according to claim 2 is the optical measurement device according to claim 1, wherein the sample holding portion is formed by bending so as to straddle the vicinity of the center of the sample holding surface. It further has a guide member that forms a space for holding the sample solution therebetween.

  An optical measuring device according to a third aspect is the optical measuring device according to the first or second aspect, wherein a plurality of the excitation light transmission fibers are provided.

  An optical measurement device according to a fourth aspect is the optical measurement device according to the third aspect, wherein a plurality of the fluorescence transmission fibers are provided.

  The optical measurement device according to claim 5 is the optical measurement device according to claim 4, wherein the plurality of fluorescent transmission fibers are provided such that their fluorescent emission side end faces form a straight line. It is characterized by.

  The optical measurement device according to claim 6 is the optical measurement device according to claim 5, wherein the connector attached to the ends of the plurality of fluorescent transmission fibers has a rectangular parallelepiped shape, and is arranged at a predetermined position of the light detection unit. It is characterized by being fitted.

  The optical measurement device according to claim 7 is the optical measurement device according to any one of claims 3 to 6, wherein the light source unit has a plurality of types of light whose wavelengths are different from each other and whose light amount can be controlled. A plurality of pumping light transmission fibers are divided into a plurality of pumping light transmission fiber bundles so as to correspond to the respective light emitting diodes, and light emitted from each of the plurality of types of light emitting diodes. Are mixed with each other in the sample solution.

  According to the optical measurement device of the present invention, the direction of the excitation light irradiated onto the sample solution from the end surface on the excitation light exit side is substantially opposite to the direction of the light incident on the end surface on the fluorescence incidence side. There is no excitation light directly incident on the surface, and even if the excitation light is reflected or scattered by the interface between the sample solution and its external environment, the excitation light incident on the fluorescence incident side end face is small. As a result, more accurate fluorescence measurement can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic side view which shows the optical measuring device 1 which concerns on embodiment of this invention, and notched the housing | casing so that the inside could be seen. It is an expansion schematic side view for demonstrating the inside of the optical measuring device 1 same as the above. It is an expansion schematic plan view of the sample holding part 5 of the optical measuring device 1 same as the above. The sample holding part 5 which deform | transformed the guide member 52 of the optical measuring device 1 same as the above is shown, Comprising: (a) is an expansion schematic side view, (b) is an expansion schematic plan view. The state of the sample solution S in the optical measuring device 1 same as the above is shown, (a) is an enlarged schematic side view in the direction orthogonal to FIG. 2, and (b) is a plan view. It is a schematic side view which shows the usage method of the optical measuring device 1 same as the above. It shows the vicinity of the fluorescence emission side end face 40b of the optical measurement apparatus 1 'as above, (a) is an enlarged schematic side view, (b) is an enlarged schematic side view in a direction orthogonal to (a), (c). Is an enlarged schematic bottom view. It is a top view which shows typically arrangement | positioning of the excitation light emission side end surface 30b and fluorescence incident side end surface 40a of the optical measuring device 1 'same as the above. It is an expansion schematic side view which shows the form which deform | transformed the light source part 2 and the excitation light transmission part 3 of the vicinity of the optical measuring device 1 (or 1 ') same as the above. 10 is a characteristic diagram showing an example of the relationship between the characteristics of the sample solution S and the light amounts of the light emitting diodes 20A, 20B, 20C... In the form shown in FIG.

  Hereinafter, preferred embodiments for carrying out the present invention will be described. An optical measurement apparatus 1 according to an embodiment of the present invention analyzes a sample solution S by fluorescence measurement. As shown in FIG. 1, as a basic configuration, the optical measurement apparatus 1 has a light source unit 2, an excitation light transmission unit 3, and fluorescence. The transmitter 4, the sample holder 5, and the light detector 6 are provided. In the figure, reference numeral 1a denotes a housing, 1b denotes a partition plate, 1c denotes a base that supports the sample holding unit 5, 7 denotes a signal processing unit that processes an output signal from the light detection unit 6, and 8 denotes a light source unit 2. And a power supply unit that supplies power to the light detection unit 6 and the like.

  The light source unit 2 emits light (excitation light) applied to the sample solution S. Specifically, a light emitting diode, a laser diode, or the like is used, and the excitation light is, for example, narrow band light of visible light such as ultraviolet light or blue light.

  The pumping light transmission unit 3 transmits pumping light, and includes a plurality of pumping light transmission fibers 30, 30,... As shown in FIG. The excitation light transmission fiber 30 causes the excitation light emitted from the light source unit 2 to enter the excitation light incident side end face 30a that is one end face, transmits the light, and transmits the light from the excitation light exit end face 30b that is the other end face. S is irradiated.

  The fluorescence transmission unit 4 transmits fluorescence and is composed of a single fluorescence transmission fiber 40. The fluorescence transmission fiber 40 causes the fluorescence emitted from the sample solution S to enter the fluorescence incident side end surface 40a that is one end surface, transmits the light, and radiates the light to the light detection unit 6 from the fluorescence emission side end surface 40b that is the other end surface. To do.

  Each of the excitation light transmission fiber 30 and the fluorescence transmission fiber 40 is an optical fiber having two layers of a core and a clad. Each of the excitation light transmission fiber 30 and the fluorescence transmission fiber 40 has a generally circular end surface, and light with a predetermined angle (for example, within about 20 degrees) is incident or emitted. The excitation light transmission fiber 30 is thin, and the fluorescence transmission fiber 40 is thicker than the excitation light transmission fiber 30. Specific diameters of each of the excitation light transmission fiber 30 and the fluorescence transmission fiber 40 are appropriately determined according to the size of a sample holding surface 5a to be described later. For example, the excitation light transmission fiber 30 is about 100 μm to 200 μm, The fluorescent transmission fiber 40 can be about 1 mm. Moreover, the number of the excitation light transmission fibers 30, 30,... Is also appropriately determined according to the size of the sample holding surface 5a. In the drawing, the boundary line between the core and the clad is omitted.

  The sample holding unit 5 includes a base member 51 and a guide member 52. The base member 51 is a resin in which the excitation light transmission fibers 30, 30,... And the fluorescence transmission fiber 40 are bundled so as to be arranged in the same direction in the vicinity of the excitation light emission side end face 30b and the fluorescence incidence side end face 40a. By adhering to each other with a fixing material F or the like without a gap and by arranging both end faces 30b and 40a to be aligned, a columnar shape (for example, a columnar shape having a diameter of about 2 mm) is formed. That is, a part of the excitation light transmission unit 3 and the fluorescence transmission unit 4 also serve as the sample holding unit 5. The excitation light emission side end face 30b and the fluorescence incidence side end face 40a form a sample holding surface 5a for holding the sample solution S, as shown in FIG. Further, the fluorescence incident side end surface 40a is arranged at the center of the sample holding surface 5a, and the excitation light emitting side end surface 30b is arranged around it. In order to align both end faces 30b, 40a, the ends of the excitation light transmission fibers 30, 30,...

  As shown in FIG. 2, the fluorescent transmission fiber 40 has a connector 4A attached to its end, and the connector 4A is fitted into a predetermined location (not shown in FIG. 2) of the light detection unit 6.

  Further, the guide member 52 of the sample holding unit 5 is formed above the sample holding surface 5a and bent so as to straddle the vicinity of the center thereof. That is, the guide member 52 is a curved surface with a narrow width on the side facing the sample holding surface 5a. The curved surface is usually substantially arc-shaped. By doing so, a space for holding the sample solution S is formed between the sample holding surface 5 a and the guide member 52.

  More specifically, as shown in FIG. 2, the guide member 52 is a wire (having a cross-sectional diameter of, for example, about 200 μm) and can be formed in a substantially semicircular shape having a diameter of about 2 mm. The wire guide member 52 can be fixed to the outer surface of the base member 51 by being spirally wound. As shown in FIG. 4, the guide member 52 is provided with a cylindrical portion 52a that fits on the outer surface of the base member 51, and is integrated with a portion 52b that is formed so as to straddle the sample holding surface 5a. It can also be formed.

  When this guide member 52 is used, the sample solution S falls along the guide member 52 when dropped onto the sample holding surface 5a by the pipette P as will be described later, and as shown in FIG. It is held by the surface tension in the space formed by the sample holding surface 5a. In this way, quick measurement can be easily performed, and the held sample solution S is kept in a stable shape, so that accurate measurement can be performed. Note that the shape of the sample solution S varies depending on the viscosity and the like.

  In addition, although the speed and accuracy are easily lost, the guide member 52 may be omitted in some cases when the optical measuring device 1 is particularly simple and inexpensive.

  The light detection unit 6 detects a frequency component of fluorescence emitted from the fluorescence emission side end face 40 b of the fluorescence transmission fiber 40 of the fluorescence transmission unit 4. The light detection unit 6 is directed toward the slit 61 (for example, the width is about 20 μm to 50 μm and the length is about 1 mm) by fitting the connector 4A attached to the end of the fluorescence transmission fiber 40 into a predetermined place. Fluorescence is emitted (see FIG. 2). The fluorescence is divided (spectroscopic) into frequency components by passing through the slit 61. The intensity of the frequency component of the fluorescence is detected by being converted into an electric signal by the spectroscopic detector 62.

  An example of how to use the optical measuring apparatus 1 having the above configuration will be briefly described. A small amount of the sample solution S is dropped by the pipette P onto the sample holding surface 5a of the sample holding unit 5 as shown in FIG. And the excitation light from the light source part 2 is irradiated to the sample solution S hold | maintained at the sample holding surface 5a through excitation light transmission fiber 30, 30, ..., .... Then, the sample solution S emits fluorescence corresponding to the component, and the fluorescence is transmitted to the light detection unit 6 through the fluorescence transmission fiber 40. The light detection unit 6 detects the magnitude of each frequency component of the transmitted fluorescence. In this way, the optical measuring device 1 can specify the component of the sample solution S or detect the concentration. The output signal from the light detection unit 6 is processed by the signal processing unit 7, and a two-dimensional graph (for example, the horizontal axis is frequency and the vertical axis is intensity) is displayed on the display unit (not shown). Ground processing is performed.

  In such an optical measurement apparatus 1, the direction of the excitation light irradiated from the excitation light emission side end face 30b to the sample solution S is almost opposite to the direction of the light ray incident on the fluorescence incidence side end face 40a. There is no excitation light that is directly incident on the side end face 40a. Even if the excitation light is reflected or scattered by the interface between the sample solution and its external environment, the guide member 52, or the like, the excitation light that is incident on the fluorescence incident side end face 40a as the background is There are few. As a result, more accurate fluorescence measurement can be performed, and the background processing can be omitted when the optical measurement device 1 is characterized by simplicity and speed rather than accuracy.

  Next, an optical measurement apparatus 1 ′ in which the fluorescence transmission unit 4 is configured with a plurality of fluorescence transmission fibers 40, 40,... Will be described. The fluorescent transmission fiber 40 of the optical measuring device 1 'is thin. Specifically, the fluorescent transmission fiber 40 may be the same optical fiber as the excitation light transmission fiber 30. Then, since the base member 51 of the sample holder 5 can be formed without distinguishing the excitation light transmission fiber 30 and the fluorescence transmission fiber 40, the manufacture becomes easy, and the excitation light transmission fiber 30 and the fluorescence transmission fiber are facilitated. 40 distributions can be easily changed.

  The fluorescence emission side end faces 40b, 40b,... Of the fluorescence transmission fibers 40, 40,... Are preferably provided so as to form a straight line as shown in FIG. . This is to make the row of the fluorescence emission side end faces 40b parallel to the length direction of the slits 61 of the light detection unit 6, as shown in FIG. 7C. Then, since the amount of light that does not pass through the slit 61 and is not used for detecting each frequency component is reduced, the total area of the fluorescence emission side end faces 40b, 40b,..., That is, the fluorescence incidence side end faces 40a, 40a. The total area of... Can be reduced. Thereby, it is possible to increase the excitation light emitting side end faces 30b, 30b,... Or the fluorescence incident side end faces 40a, 40a,. become. In order to make the row of the fluorescence emission side end faces 40b parallel to the slits 61, the connector 4A has a rectangular parallelepiped shape in the same manner so that the relative positions thereof are fixed. What is necessary is just to make it fit in the predetermined | prescribed location of the light detection part 6 made like this.

  The arrangement of the excitation light emission side end faces 30b, 30b,... And the fluorescence incident side end faces 40a, 40a,... Constituting the sample holding surface 5a will be described with reference to FIG. In FIG. 8, the fluorescence incident side end face 40a is indicated by a black circle, and the excitation light emission side end face 30b is indicated by a white circle. The fluorescence incident side end surfaces 40a, 40a,... Are arranged adjacent to each other and concentrated in the vicinity of the center of the sample holding surface 5a as shown in FIG. 8 (a). As shown, the sample holding surface 5a can be arranged in a straight line near the center. Therefore, the plurality of excitation light emitting side end faces 30b, 30b,... Are arranged so as to surround the fluorescence incident side end faces 40a, 40a,. This is because the sample solution S has a height just above the vicinity of the center of the sample holding surface 5a and the amount of the sample solution S is large, so that the amount of fluorescence incident on the fluorescence incident side end surfaces 40a, 40a,. Because. When the fluorescence incident side end faces 40a, 40a,... Are arranged so as to form a linear row, the rows of the fluorescence incident side end surfaces 40a with respect to the guide member 52 above the sample holding surface 5a in plan view. Can be orthogonal or parallel (so as to be hidden by the guide member 52).

  Further, instead of these, the fluorescence incident side end faces 40a, 40a,... Constituting the sample holding surface 5a are not adjacent to each other, as shown in FIG. It is also possible to arrange them so as to be dispersed. Thereby, the fluorescence can be made incident on the fluorescence incident side end faces 40a, 40a,... From the entire sample solution S.

  The optical measurement apparatus according to the embodiment of the present invention has been described above, but the present invention is not limited to the one described in the embodiment, and various design changes within the scope of the matters described in the claims. Is possible.

  Moreover, the following form is also possible as a detailed form of the light source unit 2 of the optical measuring device 1 (or 1 ') described above. That is, when a light emitting diode is used for the light source unit 2, the light source unit 2 has a plurality of types of light emitting diodes 20A, 20B, 20C,... Can be configured. And the plurality of pumping light transmission fibers 30, 30,... Constituting the pumping light transmission unit 3 are made to correspond to each of the light emitting diodes 20 A, 20 B, 20 C,. It is divided into bundles 30A, 30B, 30C,. For example, all the excitation light incident side end faces 30a of the excitation light transmission fibers 30, 30,... Constituting the excitation light transmission fiber bundle 30A are made to face the light emitting diode 20A, and the excitation light therefrom is incident. . The same applies to the other excitation light transmission fiber bundles 30B, 30C,. Each of the excitation light transmission fiber bundles 30A, 30B, 30C,... Is preferably composed of two or more excitation light transmission fibers 30, 30,. It is also possible to configure the optical transmission fiber 30.

  Each of the plurality of types of light emitting diodes 20A, 20B, 20C,. In order to stably control the amount of light, it is preferable to control the current flowing through the light emitting diodes 20A, 20B, 20C,. Light emitted from each of the light emitting diodes 20A, 20B, 20C,... Is irradiated from the excitation light emitting side end face 30b of the sample holding surface 5a of the sample holding unit 5 and mixed with each other in the sample solution S.

  In this way, for example, the light amounts CA, CB, CC,... Of the light emitting diodes 20A, 20B, 20C,. When the sample solution S is irradiated with light under control, the curve formed by the total amount of light becomes close to the absorption curve CS. Then, it is possible to generate more appropriate fluorescence and contribute to more accurate fluorescence measurement. Preferably, in order to easily cope with various absorption curves CS, the number of light emitting diodes 20A, 20B, 20C... Is increased (for example, 10 or more) and the light wavelengths are made as close as possible. Prepare a lot. For example, when the sample solution S includes a plurality of substances to be measured, the absorption curve CS can be complicated. In addition, the light amount of light having an unnecessary wavelength is controlled to be zero.

  In FIG. 10, the maximum value of the absorbance of the absorption curve CS is set to 1, and the maximum value of the light amounts CA, CB, and CC is set to 1, and each is normalized. In FIG. 10, the absorbance of the absorption curve CS of the sample solution S has a maximum value at a wavelength of about 630 to 640 nm, the light emitting diode 20A has a light center wavelength of about 660 nm, and the light emitting diode 20B has a light center wavelength. Is about 635 nm, and the light emitting diode 20C has a center wavelength of light of about 585 nm. In FIG. 10, a curve close to the absorption curve CS of the sample solution S is created by the sum of these three types of light.

DESCRIPTION OF SYMBOLS 1 Optical measuring device 2 Light source part 20A, 20B, 20C Light emitting diode 3 Excitation light transmission part 30 Excitation light transmission fiber 30a Excitation light incident side end face 30b Excitation light emission side end face 30A, 30B, 30C Excitation light transmission fiber bundle 4 Fluorescence transmission part DESCRIPTION OF SYMBOLS 40 Fluorescence transmission fiber 40a Fluorescence incident side end surface 40b Fluorescence emission side end surface 4A Fluorescence transmission fiber connector 5 Sample holding part 5a Sample holding surface 51 Base member 52 Guide member 6 Light detection part 61 Slit 62 Spectral detector S Sample solution

Claims (7)

A light source that emits excitation light to irradiate the sample solution;
An excitation light transmission unit for transmitting excitation light;
A fluorescence transmission unit for transmitting fluorescence;
A sample holder having a sample holding surface for holding the sample solution;
A light detection unit for detecting a frequency component of fluorescence emitted from the sample solution;
With
The excitation light transmission unit includes an excitation light transmission fiber that causes the excitation light to enter the excitation light incident side end surface, transmits the light, and irradiates the sample solution from the excitation light emission side end surface,
The fluorescence transmission unit has a fluorescence transmission fiber that causes fluorescence emitted from the sample solution to enter the fluorescence incident side end surface, transmits the light, and radiates the light from the fluorescence emission side end surface to the light detection unit,
The optical measurement apparatus, wherein the sample holding surface is formed by arranging the excitation light emission side end surface and the fluorescence incident side end surface to be aligned. The optical measurement apparatus according to claim 1,
The sample holder is formed by bending so as to straddle the vicinity of the center of the sample holding surface, and further includes a guide member that forms a space for holding the sample solution between the sample holding surface and the sample holding surface. Optical measuring device. In the optical measuring device according to claim 1 or 2,
An optical measurement apparatus comprising a plurality of the excitation light transmission fibers. In the optical measuring device according to claim 3,
An optical measuring apparatus comprising a plurality of the fluorescence transmission fibers. The optical measurement apparatus according to claim 4,
The plurality of fluorescence transmission fibers are provided so that their fluorescence emission side end faces form a straight line. In the optical measuring device according to claim 5,
An optical measuring device characterized in that a connector attached to the ends of the plurality of fluorescent transmission fibers has a rectangular parallelepiped shape and is fitted into a predetermined portion of the light detection unit. In the optical measuring device according to any one of claims 3 to 6,
The light source unit has a plurality of types of light emitting diodes having different wavelengths of light to be emitted and capable of controlling the amount of light,
The plurality of pumping light transmission fibers are divided into a plurality of pumping light transmission fiber bundles so as to correspond to each light emitting diode,
The optical measuring device, wherein light emitted from each of the plurality of types of light emitting diodes is mixed with each other in the sample solution.

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