Study On Deducting Background Error In Near-Infrared Spectroscopy Analysis

During the near-infrared spectroscopy analysis, the reciprocity of thecomponent in the sample and the influence of the spectrum instrument willdestroy the spectrum of the sample. So they must be deducted to increase theveracity of the spectrum measurement. This will ensure the suitability androbustness of the calibration models. In the dissertation, the method of deductingbackground error is studied by the experiment of aqueous matrix,milk andblood glucose of the body.The main research content of the dissertation involves:Firstly, the principle of the method of deducting background error isintroduced. First of all, the principle of near-infrared spectrum measurement isintroduced;then the principle of the method of deducting background error isintroduced by the compensation of both light-paths and deducting the standardsolution;the methods of multi-date analysis are introduced: the MultivariateLinear Regression, Principle Component Analysis and Partial Least Squire. Theevaluating guidelines of the calibration models are also presented.Secondly, the suitability of the method of deducting background error in theaqueous matrix is studied. The results show that the modeling precisions ofanalytical model have raised 37.9% and the predictable precisions have raised22.5% after deducting the background error of water. So deducting thebackground error in the aqueous matrix to eliminate partially influences of theexcursion to the instrument and the strong absorption of water raises theprecision of near-infrared spectrum measurement.Thirdly, the suitability of the method of deducting background error in themilk is studied. The results show that the method of deducting background errorcannot deduct effectively the error of the reciprocity of the other components ofthe milk when measuring the fat and the protein in the milk. But when measuringthe glucose in the milk, the modeling precisions of glucose model have raised26.2% and the predictable precisions have raised 68.4% after deducting thebackground error of pure milk. So deducting the pure milk background errorwhen measuring the glucose in the milk can deduct effectively the error of thereciprocity of the other components of the milk and raises the precision of near-infrared spectrum measurement.Lastly, the suitability o the method of deducting background error in theblood glucose of the body measurement is studied. The OGTT result shows thatthe modeling and predictable precisions of analytical model aren't raisedobviously after deducting from the background. So looking for a suitablestandard matter as background to eliminate partially influence of the excursion tothe instrument is important for the noninvasive monitoring of the blood glucose.