Resíduos de agrotóxicos organohalogenados em morango por cromatografia à gás: validação de metodologia e ocorrência no estado de Minas Gerais

Abstract

A method of gas chromatography with electron capture detection for multiresidue determination of organohalogens pesticides in strawberry was validated by in-house procedures. Linearity, matrix and day effects were observed in experiments with calibration curves of analytes alpha endosulfan, beta endosulfan, sulfate endosulfan, lambda-cyhalothrin, procymidone and trifluralin with and without the matrix. Linearity was demonstrated with significant matrix effects for some analytes, and day effect. The range varied depending on the chromatographic response of the analyte. Selectivity, recovery and precision of the method were investigated by adding standards references in blank samples. Recovery percentages ranged from 74.59 % to 115.41 % with standard deviations of repeatability between 1.63 % and 20.98 % and partial reproducibility between 5.86 % and 20.98 %. Detection limit, quantification limit, decision limit and detection capacity ranged from 0.003 mg kg-1 to 0.007 mg kg-1; 0.005 mg kg-1 to 0.013 mg kg-1; 0.003 mg kg-1 to 3.128 mg kg-1; and 0.005 mg kg-1 to 3.266 mg kg-1, respectively. The performance parameters studied indicated that the validated method is suitability for the purpose of monitoring organohalogen pesticide residues in strawberry. Organohalogen residues of pesticides were detected in 47 samples of strawberry. 75 samples were analyzed in the study conducted in 2010 in the state of Minas Gerais. Three of which did not comply with the current legislation, one presented pesticide residue above the maximum allowed and two contained unauthorized pesticide for the culture