Determinação de melanina em leite em pó por infravermelho próximo e espectrometria de massas

Abstract

The melamine addition in milk on 2008 caused losses to the dairy industry and consumer health. The ingestion of these contaminated products caused the formation of crystals in the kidney in children and babies. In this regard various methods have been developed to prevent further contamination by this substance. However, most require lengthy sample preparation, using harmful reagents, generate waste, and are expensive, which often makes it impossible to use these techniques. Within this context, this work aimed to apply electrospray ionization mass spectrometry (ESI-MS/MS) and infrared spectroscopy (IRS) in the determination of melaminein powdered milk. In the first article three treatments were used in the preparation of samples for analysis by ESI-MS/MS, however only one pretreatment was efficient in removing the milk interference in analysis. The products of thisextraction showed a univariate correlation with the concentration of melamine in milk powder, showing that melamine can be quantified. The extraction of melamine was based on the formation of precipitated by addition of trichloroacetic acid and solubilization in ethyl acetate, and this technique has not been reported in the literature. Thus, melamine can be extracted in a simple and quick wayto ESI-MS/MS analysis. In the second article milk powder samples without pretreatment were evaluated by IRS and multivariate calibration. The region 4500-5100 cm - 1 showed the better calibration model, although the model for the other regions of the spectrum have been accurate. The commercial powdered milk powder evaluated was not contaminated with melamine. Thus, the results showed that the use of infrared spectroscopy and multivariate calibration allows to obtain reliable results simply and quickly, without the need for sample preparation.