The matrix effect in gas chromatographic analysis is attributed to the presence of coextractives in organic phase obtained in the extraction process. This work reports the quantification study of increased chromatographic response of four pesticides in organic extracts of tomato extracted by solid-liquid extraction with low temperature purification (SLE-LTP). The pesticides chlorpyrifos, λ-cyhalothrin, cypermethrin and deltamethrin showed an increased chromatographic response after the saturation of the chromatographic system with multiple injections of organic extracts of tomato. It was also found that the greater the retention time, the greater the matrix effect, and that the internal standard reduces the matrix effect but does not eliminate it. The matrix effect measured by the analytical curves (in acetonitrile and matrix extract) was 27% for chlorpyrifos, 46% for λ-cyhalothrin, 96% for cypermethrin and 180% for deltamethrin.
matrix effect; pesticide; GC/ECD; tomato; organic extract
