JP2001194294A - Spectrophotometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spectrophotometer allowing the temperature of a sample to be measured to arrive at predetermined temperature for a short time and minimizing the temperature irregularity between sample cells and capable of stably holding the sample cells at the predetermined temperature for a long time. SOLUTION: In a sample chamber 1, pipes 7, 8 are arranged not only to a cell block 3 but also to an open air cutting-off lid 5 and the transmission of heat to a sample to be measured is enhanced by circulating a circulating medium controlled to predetermined temperature through the pipes 7, 8 and the radiation of heat from the sample to be measured can be minimized. By this constitution, the temperature of the sample to be measured is allowed to arrive at predetermined temperature for a short time and the temperature irregularity between sample cells 2 can be minimized and the sample cells can be stably controlled to the predetermined temperature for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a spectrophotometer used as a general-purpose spectrophotometer or as a detector of a high-performance liquid chromatograph.

[0002]

2. Description of the Related Art A spectrophotometer analyzes a sample component by measuring the spectrum of light transmitted through a sample to be measured and examining the wavelength of light absorbed or transmitted by the sample. is there.

[0003] A sample cell of a conventional spectrophotometer is installed on a cell block, and the upper portion of the sample cell is covered with a lid for shutting off outside air. An optical path window is provided on the outside air blocking cover so that light from the light source can reach the sample cell. A pipe is provided in the cell block. By circulating a circulation medium controlled at a constant temperature through the pipe, the cell block receives heat and is controlled at a constant temperature. The temperature of the sample cell is controlled by obtaining heat from a contact point with the cell block by heat conduction. Furthermore, by minimizing the release of heat from the sample cell to the outside with the lid for shutting off outside air, the temperature control accuracy of the sample cell and the sample to be measured is improved,
We are trying to ensure stability of measurement accuracy.

[0004]

In the above configuration, the temperature of the sample cell is transmitted only from the bottom of the cell by the cell block, and the temperature of the sample cell is radiated from the upper surface of the sample cell and the optical path window for measurement. An error easily occurs between the temperature of the sample and the actual temperature of the sample solution, and the error increases as the control temperature shifts to a higher or lower temperature than the ambient temperature of the detector. Furthermore, the cell block is usually made of a metal such as aluminum or brass with good thermal conductivity, but if the control temperature is set at a high temperature, the cell block expands thermally and the contact point with the sample cell bottom decreases. As a result, the efficiency of heat conduction to the sample cell deteriorates. As a result, the error between the temperature of the circulation medium and the actual temperature of the sample solution becomes larger. In particular, when a large number of continuous small cells used in the present apparatus are set, a temperature difference (unevenness) in each cell tends to occur.

The present invention has been made in order to solve the above-mentioned problem. The present invention allows a temperature of a sample solution to be measured filled in a sample cell of a spectrophotometer to reach a control temperature in a short time, and furthermore, the control temperature is reduced. An object of the present invention is to provide a spectrophotometer having a temperature control device that can be stably maintained for a long time and has a control temperature unevenness between cells minimized.

[0006]

In order to solve the above-mentioned problems, a spectrophotometer according to the present invention is not limited to a cell block in which a bottom surface of a sample cell filled with a sample is in contact but also a top surface of the sample cell in which a sample cell is in contact. A circulating system that circulates a circulating medium for temperature control, that is, a circulating flow path is also provided in the outside air blocking lid to control the temperature. With such a structure, the temperature of the sample solution filled in the sample cell is controlled by heat conduction and radiant heat from the bottom surface and the top surface. Further, the heat radiated to the outside through the outside air blocking lid, which is observed in the conventional structure, can minimize the heat taken from the sample cell. Also,
Deterioration of the heat transfer efficiency to the sample cell due to thermal expansion of the cell block can be compensated for by the heat radiation from the outside air blocking lid on the top surface, and the temperature of the sample solution to be measured can be controlled in a short time When the temperature reaches the temperature, the temperature unevenness between the cells can be minimized, and the temperature can be stably maintained for a long time.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing the configuration of an embodiment of the sample chamber of the spectrophotometer of the present invention. FIG. 2 is a perspective view of the sample chamber of the present invention shown in FIG. The sample chamber 1 includes a sample cell 2 to be filled with a sample to be measured, a cell block 3 on which the sample cell 2 is placed, a sample cell frame 4 having the sample cell 2, and a lid 5 for shutting off the sample cell 2 from outside air. Have been. As shown in FIG. 1, the sample cell 2 is filled with a small amount of sample at regular intervals. In the illustrated example, the sample cell 2 has a shape in which six cells are provided in a continuous form. ing. The cell block 3 and the outside air blocking lid 5 are covered with heat insulating materials 12 and 13, respectively. Pipes 7 and 8 through which a circulating medium for temperature control flows through the cell block 3 and the outside air blocking lid 5.
Is plumbed. The pipe 7 is provided with a joint 9 and a tube A for taking in a circulating medium controlled to a specified temperature, and the pipe 8 is provided with a joint 10 and a tube C for discharging the circulating medium. ing. In the present embodiment, water is used as a circulation medium. The pipe 7 and the pipe 8 are connected by a tube B. In addition, the outside air blocking lid 5 and the heat insulating material 13
Is provided with an optical path window 11 for introducing light for measurement into the sample cell 2 and guiding light transmitted through the sample to a diffraction grating (not shown) and a detector (not shown).

The circulating water is controlled to a predetermined temperature in an external reflux device (not shown), and then starts circulating. First, the circulating water of a predetermined temperature is introduced into the pipe 7 from the tube A and the joint 9, and the circulating water is introduced into the pipe 8 once through the tube B connecting the cell block channel and the outside air blocking lid channel. It is discharged through the joint 10 and the tube C, returned to the external reflux device again, and controlled at a predetermined temperature. The cell block 3 is controlled at a predetermined temperature by the reflux water introduced into the pipe 7, and the outside air blocking lid 5 is controlled at a predetermined temperature by the reflux water introduced into the pipe 8. Sample cell 2 filled with the sample to be measured
The lower part is fixed to the sample cell frame 4 so that heat is efficiently transmitted from the cell block 3 to the sample cell 2 and the sample to be measured, and the upper part is covered with an outside air blocking lid 5. An optical path window 11 is provided on the outside air blocking lid 5, and measurement light emitted from a light source (not shown) has passed through the optical path window 11 and interacted with the sample to be measured filled in the sample cell 2. Thereafter, the light is guided to a diffraction grating (not shown) and a photodetector (not shown), and spectrophotometry is performed.

In this measurement, the cell block 3 is positioned so that each sample cell 2 is located at the position of the optical path window 11.
Moves in the direction of the arrow. This movement is performed by, for example, a rack and pinion mechanism (not shown).

In order to provide a flow path for flowing the circulating medium in the outside air blocking cover 5, a flow path for the circulating medium to flow inside the outside air blocking cover 5 may be formed, or the flow path may be excellent in heat conduction. Alternatively, a pipe made of metal such as copper may be welded to the outside air blocking lid. Further, by covering the periphery of the outside air blocking lid 5 with a heat insulating material, heat radiation to the outside air can be blocked, and more stable temperature control can be performed.

Since heat is radiated from the sample cell 2 through the optical path window 11 provided on the outside air blocking lid 5, the optical path window 11
Has a direct influence on the temperature error in the sample to be measured. Therefore, the size of the opening of the optical path window 11 must be kept to a minimum. Also, since heat is radiated to the outside air not only from the piping to the external reflux device but also from the piping in the device, to minimize the error in the control temperature, the periphery of the piping may be covered with a heat insulating material. Good.

By circulating a circulating medium for temperature control not only to the cell block 3 but also to the outside air blocking lid 5, it is possible to minimize the release of heat from the sample cell 2 to the outside. It becomes possible. Furthermore, it is inevitable that the thermal expansion of the cell block 3 caused by the difference between the control temperature and the ambient temperature reduces the contact area between the cell block 3 and the sample cell 2 and deteriorates the efficiency of heat conduction to the sample cell 2. However, it is possible to make up for this by supplying heat from the outside air blocking lid 5. As a result, the temperature of the sample to be measured can be stably maintained at the predetermined control temperature for a long time, and the reliability of the spectrophotometric measurement can be improved. In particular, this effect works more effectively when the difference between the control temperature of the sample to be measured and the ambient temperature is large. In addition, the time required for the temperature of the sample to reach the control temperature can be significantly reduced, making it extremely effective when used as a detector for devices in which the sample is constantly flowing, such as high-performance liquid chromatography. It is.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various changes may be made within the scope of the present invention described in the appended claims. be able to. For example, in the above-described embodiment, the cell block and the pipes installed on the outside air blocking lid are connected in series to flow the circulation medium.However, these pipes may be connected in parallel, or when the pipes are connected in series. In the first circulating cell block, the circulating medium gives heat to the cell block, the temperature of the circulating medium itself changes, and a slight temperature difference occurs between the cell block and the outside air blocking lid. However, when connected in parallel, this temperature difference can be almost eliminated. Although water is used as the circulating medium, a liquid having a suitable freezing point or boiling point depending on the temperature to be controlled can be used. For example,
When it is necessary to cool the sample solution to 0 ° C. or lower, a liquid having a low freezing point such as ether can be used. When it is necessary to heat the sample solution to 100 ° C. or higher, a liquid having a high boiling point such as silicone oil can be used. In the above embodiment, the absorption spectrophotometer has been described, but the present invention can also be applied to a spectrophotometer that performs spectroscopic measurement of light reflected from the surface of a sample to be measured.

[0014]

According to the present invention, in order to control the temperature of the sample to be measured, a flow path is provided not only in the cell block but also in the lid for shutting off the outside air, and the circulating medium controlled at a predetermined temperature is flowed through the flow path. By circulating through the inside of the sample, the heat transfer to the sample to be measured is improved, and the heat radiation from the sample to be measured can be minimized. This makes it possible to minimize the temperature unevenness between the sample cells, stably control the temperature of the sample to be measured at a predetermined temperature for a long time, and perform a long-term stable spectrophotometric measurement. Further, the temperature of the sample to be measured can reach a predetermined temperature in a short time, and when used as a detector of a liquid chromatograph, measurement accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration sectional view of an embodiment of a sample chamber of a spectrophotometer of the present invention.

FIG. 2 is a perspective view of FIG.

[Explanation of symbols]

 1 --- Sample room 2 --- Sample cell 3 --- Cell block 4 --- Sample cell frame 5 --- Lid for shutting off outside air 7,8 --- Pipe 9,10 --- Fitting 11- --Light path window 12, 13 --- Insulation material A, B, C --- Tube

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // G01N 30/74 G01N 1/28 K

Claims (1)

[Claims] 1. A multi-continuous sample cell for filling a sample to be measured, an outside air blocking lid having an optical path window for blocking the sample cell from the outside air and allowing measurement light from a light source to enter the sample to be measured,
A spectrophotometer comprising: a cell block for holding a sample cell; and a circulation system for circulating a temperature control medium in the cell block and the outside air blocking lid.