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配置合格的纯牛奶样本及含有三聚氰胺质量浓度范围为0.01g/L～3g/L的掺杂牛奶样本各20个,并采集其近红外光谱。以牛奶中掺杂三聚氰胺浓度为外扰,构建二维相关同步谱,研究其相关谱特性。在此基础上,结合偏最小二乘判别分析法(PLS-DA)建立定性模型,可以实现纯牛奶与掺伪牛奶的定性鉴别,正确识别率达100%。同时,将二维相关近红外同步谱矩阵与偏最小二乘法(PLS)结合起来,建立定量分析牛奶中掺杂三聚氰胺的数学模型。对未知样品的预测相关系数R达到0.98,预测均方根误差(RM-SEP)为0.18g/L,说明基于同步相关谱矩阵建立定量分析的数学模型是可行的。该方法无需样品处理,成本低,为快速检测掺伪牛奶提供了一种新的途径。
Qualified samples of pure milk and 20 samples of dyed milk containing melamine with concentration range of 0.01g / L ~ 3g / L were collected and their NIR spectra were collected. The concentration of doping in milk as external disturbances, the construction of two-dimensional correlation spectrum, study the correlation spectral characteristics. On this basis, combined with Partial Least Squares Discriminant Analysis (PLS-DA) to establish a qualitative model, can be qualitative identification of pure milk and adulterated milk, the correct recognition rate of 100%. At the same time, the mathematical model of quantitative analysis of melamine doped in milk was established by combining two-dimensional correlation near-infrared synchronous spectral matrix with partial least squares (PLS). The predicted correlation coefficient R of unknown sample is 0.98 and the prediction root mean square error (RM-SEP) is 0.18g / L, which shows that it is feasible to establish a mathematical model based on synchronous correlation matrix. The method requires no sample processing and has low cost and provides a new way for rapid detection of adulterated milk.