JPS58193438A - Dual-wave length photometer type absorptiometer - Google Patents

Abstract

PURPOSE:To eliminate the error due to the difference in measuring positions of two lights by a photometer wherein lights from two semiconductor light emitting devices are irradiated to a sample at the substantially same point so that the measured locations in the sample become substantially identical to each other. CONSTITUTION:LEDs 1, 2 having a long life and rapid on-off response are used as light sources. The light from LED1 which emits a light with wavelength suitable for measuring the objective component and the light from LED2 which emits a light with wavelength suitable for measuring suspended matters (SS), are irradiated to a sample cell at the substantially same point using optical fibers 3 arranged in close relation to each other. Both LED's are alternately lit up to avoid an overlap of their light emitting periods and to irradiate the sample cell separately. Then, the intensity of each transmitted light is measured by a photoelectric counter 8.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in an absorption photometer for performing analysis.

In general, when measuring a colored sample with a single photometric absorption photometer, suspended matter and floating matter (hereinafter referred to as SS components) contained in the sample solution cause light scattering, so the measurement is difficult. This was a source of noise, making accurate concentration measurements difficult.

For this reason, light with a wavelength that is not absorbed by the sample component to be measured is used to measure the SS component, and is projected at the same time as light with a wavelength that is absorbed by the sample. A three-wavelength photometric spectrophotometer is used to measure the concentration of the target component based on , or the ratio. Most of these use tungsten lamps or halogen lamps as light sources, and in the case of three-wavelength photometry, the equipment is large because it uses filters, optical systems, and rotating sectors to select each wavelength. In addition, the life of the light source lamp is short, and its maintenance requires a lot of effort and expense.

In order to eliminate the above-mentioned drawbacks, the present invention uses a semiconductor light emitting device (LED) with a fast blinking response and a long life as a light source, and uses an optical fiber as a light transmission element to obtain a wavelength suitable for measuring the target component. The light emitted by a semiconductor light-emitting element that emits light of a wavelength suitable for SS component measurement and the light emitted by a semiconductor light-emitting element that emits light of a wavelength suitable for SS component measurement are connected to a sample cell by an optical fiber that guides both lights. The two semiconductor light emitting devices are arranged to irradiate almost the same point, and each light emitting device is turned on alternately so that the light emitting periods of the two semiconductor light emitting devices do not overlap, and the sample cell is irradiated, and the analyte in the cell and The transmission device absorbs and scatters the light attenuated by the SS component, and receives the light with a photoelectric conversion element, converts it into an electrical signal, amplifies it with a conversion amplifier, and performs measurements by synchronous rectification and operating an indicator etc. according to the blinking period. It is configured as follows. With this configuration, the life of the light source is significantly longer than that of conventional absorption photometers, and the blinking response of the light source is faster, eliminating the need for mechanical means such as a rotating sector, and the use of two semiconductor light emitting elements. A high-performance three-wavelength photometry method that eliminates errors due to photometric position differences between the two lights, as the measurement site in the sample can be placed at approximately the same position by irradiating the light from the same point on the sample. A spectrophotometer can be provided.

FIG. 1 is a diagram showing essential parts of a measurement system of an embodiment of a three-wavelength photometric absorption photometer according to the present invention.

In the figure, / is a semiconductor light emitting device (light emitting diode LED) that emits light with a wavelength λ suitable for measuring the target component, and / is a semiconductor light emitting device (light emitting diode) that emits light with a wavelength λ suitable for measuring the SS component, which is different from /. It is a light emitting element.

These semiconductor light emitting devices/, are connected to the power supply circuit from the power supply circuit.
The second light emitting element f/2 is designed so that the light emitting periods of both light emitting elements f/
Pulse voltages having the waveform shown in the figure are alternately supplied, and the self-luminous elements / and 2 are thereby set to emit pulse light at the intersection r7).

Wavelength λ, λ+ emitted from self-luminous element /, -
The 2.1° light passes through the inlets - and 5 of the optical fibers 3, brings the optical fibers 3 from the inlets + and 5 into close contact with each other, and enters the inside of the cell from the injection port 6 of the optical fiber 3 provided on the sample self-surface. The light that is projected onto approximately one point on the sample and transmitted through the puller reaches the light receiving section g consisting of a charge conversion element. At this time, the light with wavelength λ is absorbed and scattered by the colored sample to be measured in the sample cell, and the light with wavelength λ2 is absorbed and scattered only by the SS component in the sample, and the light is attenuated and reaches the light receiving part g. reach.

The light that reaches the light-receiving part g is converted into an electrical signal by the photoelectric conversion element, but this electrical signal was previously pulsed alternately so that the light of both wavelengths λ and λ did not overlap. The signal amplified by the amplifier is 2,λ
By separating both signal components using a synchronous rectification circuit 1 2 and measuring the difference or ratio between the two, an output corresponding to the target component concentration can be obtained.

The device is configured to be able to detect the concentration using a meter or the like.

FIG. 3 shows an example in which the concentration of creatinine in a sample containing suspended matter (chyle serum) was measured using the spectrophotometer according to the present invention. As shown,
There is sufficient linearity between the sample concentration and the actual value (g & luminous intensity), demonstrating that the accuracy is good.

According to the present invention, it is possible to provide a high-performance three-wavelength absorption spectrophotometer with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the main parts of the measurement system of an embodiment of the three-wavelength photometric absorption photometer according to the present invention. Ω is a diagram showing an example of the waveform of a pulse voltage power supply that is supplied to two semiconductor light emitting devices that emit light of three wavelengths so that the light emission (blinking) periods of both light sources do not overlap. FIG. 3 is a diagram showing the results of measuring the correlation linearity between the concentration of a test sample and absorbance with respect to the concentration of creatinine in chyle serum using the spectrophotometer according to the present invention. /...Semiconductor light emitting device that emits light with wavelength λ, S...
Semiconductor light emitting device that emits light with wavelength λ, 3-yt,
Fiber, da, s...Introduction of light into optical fiber ["
, 6... Light injection port, 7... Sample cell, g... Light receiving section consisting of a photoelectric conversion element. Applicant Toa Denpa Kogyo Co., Ltd.

Claims (1)

[Claims] (1) A sample cell is irradiated with light or radiation from two light sources with different wavelengths, and the amount of light (radiation Is amount) that is absorbed and scattered by the sample material in the sample cell and is attenuated is transferred to a photoelectric conversion element. It is a spectrophotometer that measures the concentration of a substance component in a sample based on the difference or ratio of signals corresponding to the amount of transmitted light by two wavelengths of light, which is received by a light receiving part and converted into an electrical signal. a semiconductor light emitting element that emits light at a wavelength suitable for measuring suspended solids; an optical fiber that causes the two semiconductor light emitting elements to alternately emit light; A dual-wavelength photometric type % type % type characterized by comprising a light receiving section consisting of a photoelectric conversion element arranged to receive emitted light through a sample material in a sample cell.