[Fast determination of melamine content in milk base on Vis/NIR spectroscopy method].

In order to investigate the feasibility of near infrared reflectance spectroscopy (NIRS) method for detecting if milk was adulterated with melamine or not, the present work has done the following research. Through adulterating different content of melamine into pure milk, altogether 160 samples were prepared. Using the Handheld Field Spec spectrometer spectral data of the samples were obtained, followed by different pretreatment methods to carry on processing the spectrum data, then establishing the mathematical model separately through comparison with different calibration models using different pretreatment methods, thus we got smoothing of moving average as the pretreatment method. One hundred twenty samples were taken out ran domly from 160 samples (all) to set model, with the remaining 40 samples as the validation samples. Two discriminant analysis models were developed by using partial least squares (PLS) method and least squares-support vector machine (LS-SVM) metho respectively, and then the other 40 samples were used to test the performance of the models. The coefficients of correlation (r) between the real values and the discriminant analysis models predicted ones were 0.917 4 (PLS) and 0.910 9 (LS-SVM). The root mean standard errors of prediction (RMSEP) were 0.030 4 (PLS) and 0.046 7 (LS-SVM). The results of this study indicated that NIRS method could provide rapid determination for melamine in milk.