Comparison Between Three Chromatographic (GC-ECD, GC-PFPD and GC-ITD-MS) Methods and a UV-Vis Spectrophotometric Method for the Determination of Dithiocarbamates in Lettuce

摘要

The purpose of this study was to compare the performance of gas chromatographic with electron capture detector, pulsed flame photometric detector and mass spectrometry (GC-ECD, GC-PFPD and GC-MS) and UV-Vis spectrophotometric methods, based on acidic hydrolysis with tin(II) chloride of dithiocarbamate and analysis of the evolved CS 2 . For the validation studies were assessed linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy and precision. Recovery experiments were performed at 0.05 and 0.4 (chromatographic method) and 0.4, 0.8 and 2.0 mg CS 2 kg -1 (UV-Vis spectrophotometric method). The analytical curves were linear from 0.08 to 2.0 ?μg CS 2 mL -1 (chromatographic method) and from 0.4 to 2.2 ?μg mL -1 and from 2.2 to 8.9 ?μg CS 2 mL -1 (both with r 2 > 0.995) (UV-Vis spectrophotometric method). Method LODs were 0.01 and 0.28 mg CS 2 kg -1 and LOQs were 0.02 and 0.4 mg CS 2 kg -1 for the chromatographic and spectrophotometric methods, respectively. Acceptable accuracy was obtained for both methods (RSDs < 15.9% and recoveries from 87.7-107.4%). There was no significant difference between the techniques and detectors employees.