JPH0686060U - Total reflection spectrophotometer - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide a total reflection spectrophotometer having a prism structure that enables the application of the total reflection method even in the spectroscopic measurement of a trace amount of a dissolved substance. [Structure] The sample contact surface of the prism of the total reflection spectrophotometer is curved along the optical path direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a total reflection spectrophotometer suitable for spectroscopic analysis of a trace amount of melt.

[0002]

[Prior art]

 Conventionally, the spectroscopic measurement of a trace amount of a dissolved substance has been performed exclusively by a transmission method or a diffuse reflection method.

Here, in the transmission method, a small amount of a dissolved substance is put in a cell such as glass or spread on an infrared transmitting material, and the light is irradiated to the light to be transmitted through the cell or the like. In the diffuse reflection method, the infrared reflection plate such as Au or Ag is coated with a sample together with a standard reflection material such as KBr, and the sample is irradiated with light to reflect the light reflected from the plate. It is something to detect.

[0004]

[Problems to be solved by the device]

 However, in the transmission method, there is a problem that the thickness is reduced due to the spread of the solution, and in the diffuse reflection method, there is a problem of deliquescent property of an alkali halide such as KBr used as a standard reflection material.

Therefore, for example, a total reflection method other than the above may be used, but the prism used in the total reflection method has the configuration of FIG. 3 (FIG. 3A is a side view, FIG. (b) shows the view as seen from the optical path direction.) When the solution is brought into close contact with the prism, the solution spreads to a position outside the optical path (total reflection point), increasing the area that does not contribute to absorption. There is a drawback that it will end up. In FIG. 3, 21 is a prism, 22 is a sample, and a is a total reflection point.

Therefore, it is an object of the present invention to provide a total internal reflection spectrophotometer having a prism structure which enables the application of the total internal reflection method even in the spectroscopic measurement of a trace amount of dissolved substance.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is directed to a total reflection spectrophotometer in which a sample is attached in close contact with a prism, and the sample surface is irradiated with light through the prism. Characterized by being curved.

Here, the prism may be an optical material capable of transmitting infrared rays, such as KRS-5, ZnS, and ZnSe. However, the prism is not limited to these, and the shape of the prism may be a triangle, a trapezoid, or the like. .

Light is incident on the prism by narrowing the light from the light source with a beam condenser, and the incident angle must be larger than the critical angle so that the incident light is totally reflected at the boundary surface. Further, as the light source, for example, a heat radiator such as a grover, a Nernstrouer, or a nichrome wire is used.

The prism is curved downward so as to collect the sample without flowing out. The curved portion may be formed either by putting it in a mold or the like when forming the prism and by molding, or by cutting a flat prism into a curved shape after forming it. The bending ratio of the curved portion is determined by the amount of sample solution.

The prism is curved along a line connecting the total reflection points of light within the prism, that is, along the optical path direction.

The sample to be measured in the present invention includes, but is not limited to, a trace amount of oil in water and plastic in an organic solvent.

[0013]

[Action]

 In the present invention, since the sample can be collected in the curved portion of the prism, the solution does not spread out of the optical path.

[0014]

【Example】

 The structure of the prism of the device of the present invention will be described with reference to the drawings. FIG. 1A shows a side view, and FIG. 1B shows a view seen from the optical path direction. Reference numeral 1 is an optical material capable of transmitting infrared rays, for example, a prism having a trapezoidal cross section formed by KRS-5. The upper portion of the prism is curved inward as shown in FIG. Is formed. A sample is stored in the deepest part of the groove 6, and the deepest line becomes the reflection line 3.

The measurement light (infrared ray) indicated by the broken line in the figure enters from the incident surface 2 and is reflected on the reflection line 3 indicated by the alternate long and short dash line. The incident surface 2 is set to form an angle of 45 degrees with respect to the reflection line 3, and infrared rays are incident on the incident surface 2 at an angle of 90 degrees, so that the incident surface 2 is reflected on the reflection line 3. Total internal reflection occurs. A in the figure indicates a total reflection point.

The infrared light totally reflected on the reflection line 3 is also reflected on the opposite surface 5 of the reflection line 3 and finally exits from the emission surface 4 to the outside. The opposite surface 5 may be coated with Au, Ag or the like in order to promote reflection of infrared light.

With the above configuration, the measurement of a trace amount of dissolved substance is performed as follows. A small amount of the dissolved substance is dropped into the groove 6 of the prism 1 with a pipette or the like. Then, the solvent of the trace amount dissolved material is volatilized or evaporated so that only the sample component 7 remains in the deepest part of the groove 6. After the solvent volatilizes or evaporates, the light (infrared light) from the light source is narrowed down by the beam condenser, made incident from the incident surface 2 in the direction of the broken line in the figure, and reflected on the reflection line 3. Here, since the sample component 7 remains on the reflection line 3, the wavelength component corresponding to the characteristic of the sample is absorbed and the other wavelength components are reflected.

The light reflected on the reflection line 3 is reflected on the opposite surface 5 and sent to the reflection line 3 again. By repeating these (due to multiple reflection of light), the contact area between the light and the sample can be increased, and a spectrum with strong absorption can be obtained.

After the multiple reflection, the light exits from the exit surface 4 and is detected by a detector (not shown) to obtain an infrared spectrum.

Although the prism has one curved surface (groove) in the above description, for example, a plurality of curved surfaces may be formed as shown in FIG. In FIG. 2, 1'denotes a prism, and 11, 12, and 13 denote grooves, respectively. The material of the prism and the incidence of the measurement light are the same as in FIG.

In this embodiment, different samples may be put in the grooves 11, 12 and 13, respectively, and the plurality of grooves may be irradiated with the measurement light at the same time, but the incident position of the measurement light is fixed at one position. Then, the prism 1 ′ may be moved as indicated by the arrow in FIG. 2 so that the grooves of the prism 1 ′ are sequentially provided there. As the moving mechanism of the prism, a known moving mechanism such as a rack and pinion mechanism can be used.

Further, in combination with a liquid chromatograph or the like, the release liquid from the liquid chromatograph may be sequentially put into the grooves 11, 12, 13.

[0023]

[Effect of device]

 According to the present invention, since the sample can be efficiently collected on the prism on the optical path, the same effect as the concentration can be obtained. Therefore, for example, analysis of oil in water, which is currently extracted using carbon tetrachloride, etc., can be measured simply by evaporating water on the prism, and carbon tetrachloride is unnecessary.

Further, a fixed amount of the solution can be dropped on the prism for quantitative measurement.

[Brief description of drawings]

FIG. 1 (a) is a side view of the prism of the present invention, (b)
Is a view of the prism of the present invention viewed from the optical path direction.

FIG. 2 shows another embodiment of the present invention.

3A is a view of a conventional prism viewed from the side, and FIG. 3B is a view of the conventional prism viewed from the optical path direction.

[Explanation of symbols]

 1, 1 ', 21: Prism 2: Incident surface 3: Reflection line 4: Emission surface 5: Opposite surface 6, 11, 12, 13: Groove

Claims (1)

[Scope of utility model registration request] 1. A sample is attached in close contact with a prism,
A total reflection spectrophotometer for irradiating a sample surface with light through a prism, wherein the sample contact surface of the prism is curved along the optical path direction.