Study On Instrument Of Blood Glucose Measurement Based On Mid-IR Transmission Spectroscopy

Blood glucose monitoring is vital for the diabetics. The conventional methodshave to consume the biochemical reagents and last a long measuring period. So weattempt to achieve the blood glucose measurement by optical method. This paper isconcentrated on the methodology and instrumentation for blood glucose measurementbased on Mid-IR ATR spectroscopy, for it not only provides an economic way toavoid biochemical test methods, reduce material wastage and speed up measurement,but also it is the important base of non-invasive blood glucose measurement.We used FT-IR spectrum to design a serial of experiments. Through theseexperiments proved the feasibility of measuring the concentration of blood glucose byFT-IR method and it could achieve high precision. We got the approximately value ofoptimal pathlength of Mid-IR single variable of whole blood by the theory of optimalpathlength in IR spectrum.Based on the method and result mentioned above, we built a sample instrumentfor blood glucose measurement in terms of single and multi-wavelength, in which anew model miniature CO2 laser was used as the IR source and the pyroelectricdetector as the detection device. In order to change the output wavelength wedesigned a control system consist with the motion controller and the linear actuator. Adual beam scheme has been adopted for the optical setup. Also, we developed therelevant software for the data acquisition and analysis. The signal-to-noise ratio (SNR)of the instrument is 10000:5 and the stability is approximately 6‰ by transmissionmethod. We finished the experiments of glucose in water solution and whole blood bytransmission, the single wavelength is 1080cm-1 and the result coefficient of wholemodel is 0.975 in this device. Through comparing the transmission and ATR method,we think the transmission method add the measurement pathlength and made it moreaccess to the optimal pathlength,so it can get higher measurement sensitivity thanATR method and the consume of sample can decrease from 2ml to 0.05ml bytransmission. Finally we attempted the multi-wavelength method by using thismeasurement system.