Produção do material de referência de oxitetraciclina em leite em pó desnatado

The NBR ISO/IEC 17025:2005 standard describes the managerial and technical prerequisites for implementing quality management systems in test and calibration laboratories and stresses the importance of assuring the quality of the analytical results. Reference materials (RM) and certified reference materials (CRM) are recommended for this purpose. RM and CRM are being used increasingly in laboratories for analytical quality control, equipment calibration and methodology development, all of which require reliable, traceable measurements. Demand for these materials for veterinary drug residues far outstrips current production capacity. In Brazil there are not yet any producers of RM for veterinary drug residues in food, which hampers access to such products and raises costs for the country’s laboratories. The aim of this study was to produce a RM for an antibiotic, oxytetracycline, in a milk matrix, using a naturally contaminated milk and lyophilization (freeze-drying) as the preservation technique. The determination of the concentration was performed by liquid chromatography coupled with sequential mass spectrometry (LC-MS/MS). The lots of MR 1 and 2 produced were sufficiently homogeneous, with an average concentration of 177.3 and 165.1 µg/L, respectively. The batches were considered sufficiently stable for six months stored at (-20 ± 1 ° C) and (6 ± 1 ° C) and for seven days at (6 ± 1 ° C) and (40 ± 1 ° C). It was concluded that the lyophilization technique proved to be adequate as a drying process for the production of oxytetracycline containing milk matrix. The production of this MR of oxytetracycline in milk in Brazil will allow the improvement of the quality of the analyzes of the food laboratories and consequently in the support to the actions of control and sanitary inspection, besides the possibility of the elaboration of a proficiency test.