JPH10281987A - Spectrophotometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve maintainability, and size and cost reduction by forming a sample sucking mechanism for a flow cell using an electromagnetic pump. SOLUTION: A spectrophotometer is provided with a flow cell 3, an electromagnetic pump 8, a waste liquid tube 9, a suction nozzle for sample 6 and so on. The pump 8 operates on pulse exciting given by a control circuit 5, sucks the sample 6 to the flow cell 3, and discharged through a tube 9 after the completion of measurement. Regulating frequency of pulse exciting optimizes sucking accuracy under conditions of a flow passage such as piping inside diameter and sample viscosity. The suction nozzle, pump 8 and the tube 9 are composed of Teflon series material, which is capable of measuring a sample such as organic solvent. Sample suction requires the tube to be drawn through hands, therefore, there is not any aging change in suction amount due to tube deterioration, and the pump 8 of small type and low power model is available for operation, thereby reducing an installation space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spectrophotometer.

[0002]

2. Description of the Related Art Generally, a method using a square cell and a method using a flow cell are known as methods for installing a sample in a measuring section in order to perform photometry of the sample.

A method using a square cell is advantageous in reproducibility of measurement results because measurement is performed without the influence of carryover or contamination, but the cell must be replaced each time another sample is measured. Therefore, a method using a flow cell is advantageous for continuous measurement of different samples. As a method for sucking a sample into the flow cell, there is a peristaltic pump for sucking the sample by squeezing a tube, and the configuration thereof is shown in FIG.

[0004]

The peristaltic pump rotates the rotor to move the liquid in the flow path by squeezing the tube. Therefore, the material of the tube must be excellent in elasticity and excellent in durability. The most frequently used tube material is vinyl chloride. However, vinyl chloride-based materials have poor chemical resistance to organic solvents such as toluene and xylene, and strongly acidic samples such as concentrated sulfuric acid, and the life of the tube is extremely shortened. Further, the peristaltic pump strongly stiffens the tube without using a sample that shortens the life of the tube as described above, so that the tube is deteriorated and the tube needs to be periodically replaced. In addition, since the suction amount changes with the deterioration of the tube, the suction accuracy is poor and the suction amount needs to be corrected. Further, the peristaltic pump requires the use of a motor having a large torque in order to rotate the rotor and squeeze the tube, so that the power supply capacity and the installation space are increased, resulting in an increase in the size of the apparatus and an increase in production costs. SUMMARY OF THE INVENTION An object of the present invention is to provide a small-sized, low-cost spectrophotometer which improves the maintainability by forming a flow path including a tube with a material having excellent chemical resistance and a long life.

[0005]

According to the present invention, as a means for solving the above-mentioned problems, a magnetic field is applied to the electromagnet by applying a pulse current 15 to an electromagnet 13 as shown in FIG. A small electromagnetic pump having a structure for sending liquid by applying thrust for generating reciprocating motion to the magnet 14 is employed to simplify the sample suction mechanism, and furthermore, the flow path of the sample including the tube is chemically resistant. It is made of a material with excellent properties.

[0006]

FIG. 1 shows an embodiment in which the present invention is applied to a spectrophotometer. White light emitted from the light source 1 is split into monochromatic light by the spectroscope 2, transmitted through the flow cell 3, and provided to the light receiver 4. On the other hand, the flow path of the sample 6 includes the suction nozzle 7, the flow cell 3, and the waste liquid tube 9.
And the electromagnetic pump 8 are connected in order. Photometry of the sample 6 with the spectrophotometer configured as described above is performed in the following procedure.

[0007] The suction nozzle 7 is inserted into the sample 6, and the electromagnetic pump 8 is operated by the control circuit 5 to fill the flow cell 3 with the sample 6. The monochromatic light is emitted from the spectroscope 2 to the sample 6 filled in the flow cell 3 by the electromagnetic pump 8 and the flow cell 3
And is given to the light receiver 4. The light provided to the light receiver 4 is converted into an electrical signal by an amplifier circuit 10 and processed by a control circuit 5 to determine the absorbance or transmittance.
When the sample 6 after measurement is discharged to the outside of the apparatus, the electromagnetic pump 8 is operated by the control circuit 5 as in the case of suction, and the sample 6 filled in the flow cell 3 is passed through the electromagnetic pump 8 and the waste liquid tube 9 to the outside of the apparatus. To be discharged.

The electromagnetic pump 8 operates by alternately applying a pulse of a voltage having both positive and negative polarities. The pulse application is given by the control circuit 5. The pulse energization given by the control circuit 5 is set so that the number of pulses can be controlled and the suction amount of the sample 6 can be adjusted. Also, the frequency and duty ratio of the pulse current can be adjusted, and the setting is made so that the suction accuracy can be optimized under the conditions where the flow path is placed, such as the inner diameter of the pipe and the viscosity of the sample.

In a device using a peristaltic pump as the sample suction mechanism, the tube is sucked by suction. Therefore, the suction amount once set may change with deterioration of the tube. By using the electromagnetic pump, it is not necessary to squeeze the tube 9 and it is not necessary to correct the suction amount due to the deterioration of the tube.

The suction nozzle 7, the electromagnetic pump 8, and the waste liquid tube 9 are made of a Teflon-based material having excellent chemical resistance so that a sample such as an organic solvent can be measured.

Further, the installation space of the electromagnetic pump 8 is about 7
It is about 0cm ³ and can be installed in a smaller space than the peristaltic pump.

[0012]

According to the spectrophotometer of the present invention, there is no requirement for the material of the tube to be stretchable, and the tube is not required to be very strong. Therefore, a material having excellent chemical resistance can be selected for the tube. As a result, periodic maintenance is not required, and measurement of a sample that cannot be measured by a conventional apparatus using a peristaltic pump as a sample suction mechanism can be performed. In addition, the electromagnetic pump can be operated sufficiently with a small-sized and small power supply model, and the size and cost of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the present invention.

FIG. 2 is an explanatory diagram of the principle of an electromagnetic pump.

FIG. 3 is a conventional block diagram.

[Explanation of symbols]

1 light source, 2 spectroscope, 3 flow cell, 4 light receiver,
5: control circuit, 6: sample, 7: suction nozzle, 8: electromagnetic pump, 9: waste liquid tube, 10: amplifier circuit, 11: power supply circuit.

Claims (1)

[Claims] 1. A spectroscope for dispersing white light emitted from a light source into monochromatic light using a diffraction grating, and a flow cell for a measuring unit for optically measuring a reaction-treated sample, wherein the flow cell is used. In a spectrophotometer having a suction port for sucking the sample, and a sample suction mechanism for sucking the sample from the suction port and filling the sample in the flow cell, an electromagnetic pump is provided for the sample suction mechanism. A spectrophotometer characterized by using: