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This paper involves conditions and methods of high precision measurement of blood glucose concentration using Mid-IR ATR spectroscopy: (1) Comparing the spectra of saline solution, plasma, and whole blood to which adding glucose respectively, we find that in these three backgrounds with different complexity, the absorption peaks of glucose are at the same wavelengths in the band of 1200 to 900 cm' . (2) Analyzing experimental results of concentration gradient built by adding glucose to a series of plasma, we obtained a high correlation (greater than 0.98) between glucose concentration and absorbance in the band of 1200 to 900 cm-2, it provides us the feasibility of building calibration model of glucose concentration in this specific band. (3) In the process of building calibration model for glucose concentration of 40 whole blood samples (blood glucose concentration varied from 73 to 167 mg/dL, mean was 94.46 mg/dL, standard error was 17.68 mg/dL) by utilizing PLS method optimized with full cross validation, we applied genetic algorithms to the selection of optimal subsets of wavelengths, the number of wavelengths for calibration was decreased to 14 and the precision of the model was improved considerably, RMSEP was 10.56 mgldL. This proves that high precision measurement of blood glucose concentration can be achieved in narrow-band width (1200-900cm-1) when few wavelengths are selected.
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