Double-wavelength absorbance detection device for analyzing trace liquid

Abstract

The invention relates to an ultraviolet double-wavelength absorbance detection device for trace liquid. The device is formed by connecting four parts which are a light source, a liquid core waveguide sample detection tank, a photoelectric detector and a control detection circuit by a light path and a line. The light source comprises two ultraviolet light emitting diodes with different wavelengths. The sample detection tank comprises a liquid core waveguide pipe, and the two pipe orifices of the liquid core waveguide pipe are opened and are used for leading in and leading out a solution to be analyzed. The liquid core waveguide pipe is provided with two turn areas used as an incident light coupler and an emergent light coupler of the liquid core waveguide sample detection tank. The control detection circuit lightens the two light emitting diodes of the light source in a time-sharing way, the intensity of light penetrating through the liquid core waveguide sample detection tank is respectively detected at each lightening moment by the detector, and the absorbance of the liquid to be detected under two wavelengths is obtained. The invention realizes the detection of the ultraviolet double-wavelength absorbance of the trace liquid and has high detection sensitivity of the device, little consumption quantity of a sample, simple and reliable detection operation, low manufacturing cost of the device and easy miniaturization and integration.

Description

technical field [0001] The invention relates to the microfluidic analysis field of analytical chemistry, in particular to an ultraviolet dual-wavelength absorption photometric analysis and detection device for trace liquids. Background technique [0002] The field involved in this patent is the detection system research in the field of analytical chemistry microfluidic analysis. The detection system is an important part of an analysis system. Since the microfluidic analysis system is based on microchannels, the reagent consumption is only picoliters or nanoliters, so the requirements for detection methods and devices are unique. [0003] Absorption spectrophotometry is a widely used detection method, which occupies an important position in analytical chemistry, and is also one of the earliest detection methods used in microanalysis systems. Its detection sensitivity is proportional to the optical path, but due to the The sample size of the system is small, and it is diffic...

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Problems solved by technology

There are many technologies reported at present, and there are mainly the following two types that can effectively increase the optical path under the microsystem to the millimeter level: one is to use micromachining technology to make a high-reflectivity mirror inside the absorption pool (Noda, T. , Takao, H., Yoshioka, K., Oku, N., Ashiki, M., Sawada, K., Matsumoto, K., Ishida, M., Sensors and Actuators B-Chemical, 2006, 119: 245)( Steigert, J., Grumann, M., Brenner, T., Riegger, L., Harter, J., Zengerle, R., Ducree, J., Lab on a Chip, 2006, 6:1040), such techniques The longest optical path can reach 1 cm, but this technology has high requirements for micromachining, difficult parts production, and very strict requirements on the incident angle of light; another more advantageous technology is liquid core waveguide technology, the principle is to use low refractive index The material used to construct the detection cell, the difference between the measured solution and the detection cell material, thus using the principle of total reflection makes the light entering the liquid bound in the liquid and propagates along the waveguide axis, thereby obtaining a long optical path (Du, W.B.Qun , F.Fang, Z.L.Chemical Journal of Chinese Universities-Chinese, 2004, 25:610) (Du, W.B., Fang, Q., He, Q.H., Fang, Z.L., Analytical Chemistry, 2005, 77:1330), this method Sensitivity exceeding that of conventional methods can be obtained, but this type of technology requires that the incident light must be coupled from the port of the waveguide to meet the condition of the liquid core waveguide, which makes all reported systems use a tee or a quasi-tee connected to the end of the waveguide The three-way interface inevitably brings problems such as liquid leakage, interface dead volume, air bubble retention, and cleaning difficulties.

[0005] Although the reported methods for microfluidic photometric detection have effectively solved the problems of short optical path and low sensitivity in the past, there are still major problems in processing technology, cost control, interface coupling, etc., which are limited. promoted its application

Moreover, in the multi-wavelength absorption photometry, the previous scheme generally uses a continuous light source (xenon lamp, deuterium lamp, tungsten lamp) plus a spectroscopic system (grating, prism, filter) to obtain monochromatic light of different wavelengths. The disadvantages of complex system structure and high cost

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