Off-resonance dual-cavity photoacoustic cell used in noninvasive blood glucose measurement and detection method

Abstract

The invention discloses an off-resonance dual-cavity photoacoustic cell used in noninvasive blood glucose measurement and a detection method. The off-resonance dual-cavity photoacoustic cell includes a sample cell, an incidence window, a laser, a communicating pipe, an inspection room, an adjusting plate and a microphone, wherein a to-be-detected sample is placed in the sample cell; a gas cavity is formed by the space from the upper surface of the to-be-detected sample to the incidence window; the incidence window is installed at the top of the sample cell; the laser is arranged on the incidence window; the communicating pipe is arranged on the lateral surface of the sample cell and faces to the gas cavity; the inspection room is placed at the rear end of the communicating pipe and forms a detection cavity together with the adjusting plate; and the detection cavity is mutually communicated with the gas cavity through the communicating pipe. As the position of the adjusting plate in the inspection room is adjustable, the volume of the detection cavity can be changed to adapt to different modulating frequencies; and the microphone installed on the adjusting plate is used for detecting the intensity of the optical and acoustic signals. The off-resonance dual-cavity photoacoustic cell and the method solve the disadvantages that the traditional resonance type photoacoustic cell has big volume, is difficult to process and manufacture and is only suitable for single stationary modulating frequency, and can meet the requirement of blood glucose monitoring.

Description

technical field [0001] The invention relates to a photoacoustic cell for non-invasive blood sugar detection, in particular to a non-resonant double-cavity photoacoustic cell for non-invasive blood sugar detection and a method for using the photoacoustic cell for non-invasive blood sugar detection. Background technique [0002] Non-invasive blood glucose detection methods have become the development trend in the field of blood glucose detection due to less pain for patients, low chance of infection, and continuous monitoring of blood glucose changes. At present, the main non-invasive detection methods of blood glucose mainly include near-infrared spectroscopy, fluorescence spectroscopy, and photoacoustic spectroscopy. Among them, photoacoustic spectroscopy has become one of the most promising methods for clinical diagnosis and treatment because of its high sensitivity and good specificity. [0003] Photoacoustic spectroscopy is an important branch of spectroscopy. It is a ne...

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Problems solved by technology

[0006] However, most of the existing resonant photoacoustic cells are gas photoacoustic cells, while blood glucose monitoring requires solid (sample is glucose powder) or liquid (sample is glucose aqueous solution) photoacoustic cells

Moreover, the Helmholtz resonant frequency is determined by the volumes of the two cavities and the connecting cavities, so a big disadvantage of the Helmholtz resonant photoacoustic cell is that the size of the connecting tube cannot be changed when the modulation frequency changes. Retuning, that is, the Helmholtz resonant photoacoustic cell is suitable for a single fixed modulation frequency

When the modulation frequency changes, its resonance effect will be greatly reduced, thus losing its meaning

In addition, when the modulation frequency is low (this is the requirement for blood glucose monitoring), the volume of the connecting tube must be large enough, and the diameter of the gas pipeline connecting the two connecting tubes is very small, which is not easy to realize in the processing technology.

Therefore, the traditional Helmholtz resonant photoacoustic cell is not suitable for the requirements of blood glucose monitoring

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