Application of Mid-Infrared Transmission Spectrometry to the Direct Determination of Glucose in Whole Blood

The capability of FT-IR transmission spectrometry was examined for the direct determination of glucose in whole blood without any sample preparation. For these investigations, the whole blood samples were automatically aspirated by a syringe pump into the transmission cell. Infrared spectra were recorded in the 1500–900 cm −1 range. Despite the high water background absorption and the complex blood matrix, significant spectral changes due to different glucose concentrations were observed. Chemometric (partial least-squares) models were applied for the determination of glucose. A standard error of calibration of 13.8 mg/dL was obtained by using a partial least-squares calibration model containing five ranks. The residues for an independent test set were less than 15 mg/dL.