Melamine is also a residue in the chemical industry, it can also be found in residual water. If residual water is not adequately purified, melamine can move to drinking water, and be taken by humans. The ingestion of products contaminated with melamine has been related to renal diseases, urolithiasis and bladder cancer in both animals and humans. Safety limit of melamine ingestion has been officially set by the US FDA at 2.5 ppm for adult’s food, and at 1 ppm for infant formula. Therefore, a reliable method is needed to determine melamine residues in food as milk and dietetic supplement, particularly in products for children. Therefore, the possible melamine-contamination level of the farm animals must be evaluated by the analysis of the kidney. In this work, several liquid chromatographic procedure using micellar mobile phases of sodium dodecyl sulphate (SDS), and eventually an organic modifier, buffered at pH 3, a C18 column and UV detection were reported for the determination of melamine in < 15 min in milk, dietetic supplements, serum, urine, waste and drinking water and swine kidney. Samples were diluted with a SDS solution, filtered and directly injected, thus avoiding long extraction and experimental procedures. The optimum mobile phase composition was taken using a experimental design. For each case, melamine was eluted in < 15 min without interferences from the matrix compounds. Validation was performed following the indications of FDA. The following parameters were studied: linearity, limits of detection and quantification, intra- and inter-day precision and accuracy, robustness and recovery. The proposed method was found useful for routine analysis of this kind of samples.

 

Acknowledgements: This work has been supported by projects from the Spanish Ministry of Education and Science (MEC) CTQ 2007-764473/BQU and CTQ2010−16010/BQU; the Foundation Caixa-Castelló, Bancaixa P1-1B2006-12 and by FACSA through the collaboration research projects 292 11I036.01 and 11I358.01.