A multiresidue method for the quantification of 13 sulfonamides in animal feed is described. It involves the application of a modified QuEChERS procedure followed by HPLC–MS/MS (high performance ...liquid chromatography coupled to tandem mass spectrometry) analysis. The best conditions for the extraction solution and PSA (primary secondary amine) mass were determined. After optimization, the method was validated according to the European Commission Decision 2002/657/EC. The validation levels employed were 25, 50 and 75 μg kg−1. Acceptable values were obtained for the following parameters: linearity (0.9864 < r2 < 0.9993), decision limit (50.4 μg kg−1 < CCα < 55.8 μg kg−1), detection capability (50.7 μg kg−1<CCβ < 55.8 μg kg−1), limit of quantification (0.9 μg kg−1 < LOQ < 7.1 μg kg−1), accuracy (86.0 < recovery rates < 106.8), precision (3.6 < repeatability < 19.5), (5.5 < intermediate precision < 21.6), measurement uncertainty (MU) (4.1 < MU < 32.6) and selectivity. These findings met the Codex requirements, which allow for the routine use of the method by the laboratories linked to the Ministry of Agriculture, Livestock and Food Supply of Brazil. Finally, the method was applied to real samples and only one of them showed positive for sulfamethazine, however, with a concentration below the LOQ of the method.
The determination of impurities in roast ground coffee is part of the analyses that contribute to ensuring the control of product quality. The aim of this study was to validate the methodological ...procedure of microscopy to detect and quantify the impurities husks and straw in roast ground coffee. The method is based on the principle of organic solvent extraction of the coffee fat, elimination of the fine powder by screening and sorting of the impurities husks and straw by stereoscopic microscopy. Seventy samples of roast ground coffee were collected in commercial establishments in Belo Horizonte - MG - Brazil and analysed in duplicate by three analysts, totalling 420 determinations, with the results expressed in percentages of the impurities husks and straw. The coefficients of variation under conditions of repeatability ranged from 7.0 to 27.9%, being considered satisfactory for microscopy. The analyst factor had a strong influence on the precision and accuracy of the method. The method was shown to be accurate at concentrations above 0.2% impurities. The accuracy of the method was satisfactory and the recovery in an acceptable range. The uncertainties varied with the impurity concentration range and tended to be inversely proportional. The method was considered suitable for the analysis of these impurities in roast ground coffee, and has the potential to be indicated for use in inspection procedures.
The determination of impurities in roast ground coffee is part of the analyses that contribute to ensuring the control of product quality. The aim of this study was to validate the methodological ...procedure of microscopy to detect and quantify the impurities husks and straw in roast ground coffee. The method is based on the principle of organic solvent extraction of the coffee fat, elimination of the fine powder by screening and sorting of the impurities husks and straw by stereoscopic microscopy. Seventy samples of roast ground coffee were collected in commercial establishments in Belo Horizonte - MG - Brazil and analysed in duplicate by three analysts, totalling 420 determinations, with the results expressed in percentages of the impurities husks and straw. The coefficients of variation under conditions of repeatability ranged from 7.0 to 27.9%, being considered satisfactory for microscopy. The analyst factor had a strong influence on the precision and accuracy of the method. The method was shown to be accurate at concentrations above 0.2% impurities. The accuracy of the method was satisfactory and the recovery in an acceptable range. The uncertainties varied with the impurity concentration range and tended to be inversely proportional. The method was considered suitable for the analysis of these impurities in roast ground coffee, and has the potential to be indicated for use in inspection procedures.
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