On the issue of modeling calibration dependencies of melamine in milk for an infrared analyzer

The article presents the results of modeling the calibration dependence of the melamine content in milk on its concentration in it. Currently, laboratory analysis of milk to determine its physico-chemical parameters using infrared spectrometry is regulated by current regulatory documents that do not provide for the determination of melamine using BIC analyzers, which makes it difficult for them to be used at all stages of milk processing to determine this chemical compound added for the purpose of protein adulteration.The aim of the study was to develop calibration dependencies for the detection of melamine in the milk matrix by near-infrared spectrometry.The research was conducted in stages at the Educational and Research Center for Food and Animal Feed Expertise of the St. Petersburg State University of Veterinary Medicine in 2024.A standard melamine sample, milk without melamine, was used as the study materials.At the first stage, melamine was added to milk samples in different amounts and its concentration was determined by high-performance liquid chromatography, and at the next stage, the IR spectra of the same milk samples were recorded using an infrared analyzer. At the third stage, a statistical analysis of the recorded IR spectra was performed and a calibration model of melamine in milk was constructed using the partial least squares regression method.As a result of the conducted research, a calibration model of the dependence of the quantitative content of melamine on its concentration in milk was constructed. In addition, analyzing the calculated criteria for the constructed calibration relationship, we found that it allows us to reliably determine the concentration of melamine in milk.