JPH09126997A - Optical detector for liquid chromatograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a stable analysis by reducing the influence of the temperature change of the air given to a temperature-controlled bath and at the same time, reducing the influence which an optical measurement system receives from the temperature change of the temperature-controlled bath and the change in the dimension and shape. SOLUTION: A bench 27 is fixed onto a temperature-controlled bat 22 with a bolt 29 through a spacer 28. The optical measurement system is fixed onto the bench 27, thus reducing the influence which the temperature change of the temperature-controlled bath 22 and the change in dimensions and shape give to the optical measurement system. Also, by providing a second temperature-controlled bath outside the conventional temperature-controlled bath 22, the influence with the temperature change of the air gives to the temperature-controlled bath 22 is reduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical detector used for component analysis of a column eluate of a liquid chromatograph.

[0002]

2. Description of the Related Art In a liquid chromatograph, contained components are specified by measuring some physical characteristic of a column eluate. As one of such methods, there is a method using an optical detector that measures optical characteristics such as the refractive index and light transmittance of the column eluate.

A differential refractive index detector will be described as an example of the optical detector. The differential refractive index detector is an apparatus that analyzes the components of a sample by an optical method by utilizing the fact that the refractive index of a substance has a value unique to the substance. FIG. 4 shows an example of a measurement optical system used in the differential refractive index detector. This measuring optical system mainly includes a lamp 11, a lens 12,
It comprises a slit 13, a flow cell 14, a reflecting mirror 15 and a photodetector 16. The inside of the flow cell 14 is divided into a sample cell 14a and a reference cell 14b by a transparent partition that is inclined with respect to the optical axis. When analyzing a sample, the column eluate is passed through the sample cell 14a, while the reference cell 14b is filled with the liquid used for the mobile phase of the liquid chromatograph. The light of the lamp 11 enters the flow cell 14 after passing through the lens 12 and the slit 13, and is refracted when passing through the partition wall inclined with respect to the optical axis. If the refractive index of the liquid passing through the sample cell 14a is different, the optical path of the light emitted from the lamp 11 is also different, and the position where the image of the slit 13 is formed on the light receiving surface of the photodetector 16 is also displaced. The component in the sample cell 14a is specified by examining this displacement.

The refractive index of a liquid also changes with temperature.
If the ambient temperature of the measurement optical system changes during the analysis, and the refractive index of the liquid changes as a result, this change cannot be distinguished from the change in the refractive index due to the change in the component, and thus the correct analysis cannot be performed. Therefore, in order to make a correct analysis,
It is necessary to have a temperature adjusting means for keeping the ambient temperature of the measurement optical system at a constant temperature (hereinafter referred to as “analysis temperature”) according to the analysis. An example of conventional temperature control means is shown in FIG. In FIG. 5, a temperature control means including a temperature control tank 22 for storing the measurement optical system, a heater 23 for heating the temperature control tank 22 and a heat insulating wall 24 covering the temperature control tank 22 is housed in a case 25. It is sectional drawing which shows a mode. The heat generated by the heater 23 is used for the temperature control tank 2
In order to keep the temperature of the temperature control tank 22 constant not only temporally but also spatially, the temperature control tank 22 is made of a material having a high heat conductivity and has a large heat capacity, for example, aluminum. Use block cases. The heat insulation wall 24 is for preventing heat exchange between the temperature control tank 22 and the outside air, and is made of polyethylene sponge or the like.

FIG. 6 is a view showing a state in which a measurement optical system is arranged inside the temperature control tank 22. FIG. 6A is a plan view of the measurement optical system arranged on the temperature control tank 22, and FIG.
It is an end view in the BB 'line of (a) (In addition, in these figures, the temperature control tank 22 is drawing only the bottom face part). The lamp 11 is mounted on the table 18 by the lamp holder 17.
It is fixed to. The lens 12 and the slit 13 are the base 1
9 is fixed. A flow cell 14 is attached to the table 20. The reflecting mirror 15 is fixed to the base 21. These bases 18 to 21 are directly fixed on the temperature control tank 22. The photodetector 16 is directly fixed on the temperature control tank 22 so as to be adjacent to the table 19 under the slit 13.

Even if the temperature of the measuring optical system is kept stable by the temperature control means, correct analysis cannot be performed unless the temperature of the column eluate flowing into the flow cell is stable. For this reason, a heat exchanger is used to stabilize the temperature of the column eluate at the analysis temperature before flowing it into the flow cell. FIG. 7 is a view showing a state in which the heat exchanger 26 is attached to the temperature adjusting means. The heat exchanger 26 is attached so as to be embedded in the temperature adjusting tank 22, and the column eluate introduced from the sample introduction pipe 41 is the heat exchanger 2.
Heat is exchanged with the temperature control tank 22 via 6. In this way, the column eluate flows into the flow cell 14 after its temperature is stabilized at the analysis temperature. The column eluate that has passed through the flow cell 14 flows out of the apparatus through the sample outflow pipe 42.

[0007]

When a sample is analyzed,
First, it is necessary to heat the temperature control tank with a heater to raise its temperature, and finally to stabilize the temperature within a certain fluctuation range around the analysis temperature. This fluctuation range is required to be about 1/1000 ° C. in order to perform highly accurate analysis, but in order to achieve such a high stable state, conventionally, it is 1 It took a long time of about time. Since the analysis cannot be performed during this heating, the work efficiency of the analysis was significantly impaired.

On the other hand, the temperature of the temperature control tank changes due to various external factors even after once stabilizing. Such factors include heat emitted from a lamp, temperature change of outside air, temperature change of column eluate, and the like. When the temperature of the temperature control tank changes due to these factors, the size and shape of the temperature control tank also change. If the components of the measurement optical system are directly fixed to the temperature control tank, the deformation of the temperature control tank will change the positional relationship of the components of the measurement optical system, and correct analysis will not be possible. Further, a change in the temperature of the temperature control tank is transmitted to the flow cell by heat conduction, and the refractive index of the liquid in the flow cell is changed, which also hinders correct analysis.

The present invention has been made in order to solve such a problem, and an object thereof is to stabilize the temperature of the measuring optical system in a shorter time than the conventional one, and to make the outside air Another object of the present invention is to provide an optical detector having a temperature adjusting means and a heat exchanging means which are less likely to be affected by factors such as temperature change of the above.

[0010]

A first optical detector according to the present invention made to solve the above-mentioned problems comprises a) a measuring optical system including a lamp and a flow cell as constituent parts, and b) measurement. It has a temperature control tank that stores the optical system inside and stabilizes its temperature, and c) a heat exchanger that stabilizes the temperature of the sample solution flowing from the outside of the temperature control tank into the internal flow cell. An optical detector, characterized in that d) at least each component of the measurement optical system other than the lamp is
There is provided means for fixing the constituent parts inside the temperature controlling tank in a state where the constituent parts do not come into direct contact with the temperature controlling tank.

The second optical detector according to the present invention, which has been made to solve the above-mentioned problems, comprises: a) a measuring optical system including a lamp and a flow cell as components, and b) an internal measuring optical system. A first temperature control tank for stabilizing the temperature of the sample solution, and c) a first heat exchanger for stabilizing the temperature of the sample solution flowing from the outside of the first temperature control tank to the internal flow cell, An optical detector having: d) a second temperature control tank for d) storing the first temperature control tank inside and stabilizing the temperature of the temperature control tank; and e) the above sample solution. A second heat exchanger for stabilizing the temperature of the solution before flowing into the first heat exchanger.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the optical detector according to the first aspect of the present invention, each component of the measurement optical system is placed in such a state that the component does not come into direct contact with the temperature control tank. A means for fixing inside the temperature control tank should be provided.
As a result, compared to the case where the components of the measurement optical system are directly fixed to the temperature control tank, it is possible not only to reduce the change in the positional relationship of the components of the measurement optical system due to deformation of the temperature control tank, It is also possible to reduce the influence of fluctuations in the temperature of the temperature control tank on the temperature of the measurement optical system.

Further, in the optical detector according to the second aspect of the present invention, the second temperature for stabilizing the temperature of the temperature control means is provided outside the conventional temperature control means including the first temperature control tank. The second temperature adjusting means including the adjusting tank is provided, the second heat exchanger is provided, and the liquid outlet of the second heat exchanger and the liquid inlet of the first heat exchanger are connected by a pipe. When introducing the column eluate, the temperature is stabilized by the second heat exchanger and then introduced into the first heat exchanger. This allows
Not only can the influence of the temperature change of the outside air directly on the temperature of the first temperature control tank be reduced, but also the influence of the temperature change of the column eluent due to the temperature change of the outside air on the temperature of the first temperature control tank can be reduced. can do.

[0014]

FIG. 1 shows an embodiment of the differential refractive index detector according to the present invention. In this embodiment, the base 1 for the lamp 11
8, the table 19 for the lens 12 and the slit 13, the table 20 for the flow cell 14, the table 21 for the reflecting mirror 15, and the photodetector 16 are fixed on a bench 27. As the bench 27, a member having a high strength and a low coefficient of thermal expansion, such as an Invar plate, can be preferably used, but the effect of the present invention can be sufficiently obtained even if a cost-effective aluminum plate is used. Obtainable. The area of the bench 27 is smaller than the bottom area of the internal space of the temperature control tank 22. The bench 27 is fixed to the temperature control tank 22 by a bolt 29 via a spacer 28. The spacer 28 is a disk-shaped component made of a material having high strength and low thermal conductivity, for example, ceramics, and has a hole for passing a bolt on its central axis. The cross-sectional area of the spacer 28 is made small as long as the structural stability of the bench 27 to which the measurement optical system is fixed is not impaired.

According to the above configuration, the influence of the deformation of the temperature control tank 22 on the change in the positional relationship of the components of the measurement optical system is greater than that when the measurement optical system is directly fixed to the temperature control tank 22. Can be made smaller. Further, under this configuration, the fluctuation of the temperature of the temperature adjusting tank 22 is transmitted to the bench 27 via the spacer 28, but since the contact area between the temperature adjusting tank 22 and the spacer 28 is small, the temperature is changed per unit time. The amount of heat exchanged between the temperature adjusting tank 22 and the bench 27 is also small, and therefore, compared to the case where the measuring optical system is directly fixed to the temperature adjusting tank 22, the measuring optical system with respect to the fluctuation range of the temperature of the temperature adjusting tank 22 is The ratio of the fluctuation range of the temperature becomes small. As a result, after the temperature control tank 22 is started to be heated by the heater 23, the temperature control tank 22 is heated.
The fluctuation range of the temperature is the desired fluctuation range, eg 1/1000 ° C
Before reaching, the fluctuation range of the temperature of the measuring optical system is 1/1
Since the temperature reaches 000 ° C., the time from the activation of the heater 23 to the start of analysis can be shortened.

FIG. 2 is a view showing one of other modes of the above embodiment. In this embodiment, the base 18 of the lamp 11 is
Is fixed directly to the temperature control tank 22, while the lamp 11
The measuring optical system bases 19 to 21 other than the above are fixed on the bench 27. According to such a configuration, the heat generated from the lamp 11 is not directly transmitted to the bench 27, but most of the heat flows into the temperature control tank 22 by heat conduction, so the lamp 11
It is possible to reduce the influence of the heat on the bench 27.

FIG. 3 is a schematic block diagram of an embodiment of the temperature control means and the heat exchange means according to the present invention. The temperature adjusting means in the present embodiment heats the second temperature adjusting tank 30 and the second temperature adjusting tank 30 provided so as to cover the existing temperature adjusting means including the temperature adjusting tank 22, the heater 23 and the heat insulating wall 24. The second heater 31 and the second heat insulation wall 32 for covering the second temperature control tank 30 are included in the case 25. When the sample is analyzed, the heater 23 heats the temperature adjustment tank 22 to stabilize the temperature of the temperature adjustment tank at the analysis temperature, and the second heater 31 also heats the second temperature adjustment tank 30 to increase the temperature. Stabilize the bath temperature to the analysis temperature. By providing the second temperature adjusting tank 30 in this way, it is possible to reduce the influence of changes in the outside air temperature on the temperature of the temperature adjusting tank 22.

The second heat exchanger 3 is installed in the second temperature control tank 30.
3 is attached to the temperature control tank so as to be embedded therein, and the liquid inlet of the heat exchanger 26 and the liquid outlet of the second heat exchanger 33 are connected by a pipe 43. According to such a configuration, the column eluate is brought to a temperature substantially equal to the analysis temperature by the action of the second heat exchanger 33, and then the heat exchanger 2
Since it flows into the heat exchanger 6, heat exchange between the column eluate and the temperature adjusting tank 22 in the heat exchanger 26 is stabilized. Therefore, even if the temperature of the column eluate changes due to the change of the outside air temperature, the temperature adjustment tank 22 is hardly affected by the change and stable analysis can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical detector including a bench for installing a measurement optical system.

FIG. 2 is a schematic configuration diagram of an optical detector including a bench for installing a measurement optical system other than a lamp.

FIG. 3 is a schematic configuration diagram of an optical detector including a dual temperature control tank and two heat exchangers.

FIG. 4 is a diagram showing the configuration and principle of a measurement optical system.

FIG. 5 is a cross-sectional view of an example of conventional temperature control means.

FIG. 6A is a plan view showing a state in which a measurement optical system is directly arranged in a temperature control tank. 6B is an end view taken along the line BB ′ of FIG.

FIG. 7 is a diagram showing a state in which a heat exchanger is attached to an existing temperature control means.

[Explanation of symbols]

 11 ... Lamp 12 ... Lens 13 ... Slit 14 ... Flow cell 15 ... Reflector 16 ... Photodetector 22 ... Temperature control tank 23 ... Heater 24 ... Insulation wall 26 ... Heat exchanger 27 ... Bench 28 ... Spacer 29 ... Bolt 30 ... No. Two temperature control tank 31 ... Second heater 32 ... Second heat insulation wall 33 ... Second heat exchanger

Claims (2)

[Claims] 1. A measuring optical system including a) a lamp and a flow cell as components, b) a temperature controlling tank for storing the measuring optical system inside and stabilizing its temperature, and c) an outside of the temperature controlling tank. An optical detector having a heat exchanger for stabilizing the temperature of the sample solution flowing into the internal flow cell from d), and d) at least each component of the measurement optical system other than the lamp,
An optical detector comprising means for fixing inside the temperature control tank in a state where the constituent parts do not come into direct contact with the temperature control tank. 2. A measuring optical system including a) a lamp and a flow cell as components, b) a first temperature control tank for storing the measuring optical system therein and stabilizing its temperature, and c) a first temperature. An optical detector having a first heat exchanger for stabilizing the temperature of the sample solution flowing from the outside of the adjustment tank to the internal flow cell, and d) storing the first temperature adjustment tank inside, A second temperature control tank for stabilizing the temperature of the temperature control tank, e) a second heat exchanger for stabilizing the temperature of the sample solution before flowing into the first heat exchanger, An optical detector comprising: