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Advisor(s)
Abstract(s)
Amulti-residue methodology based on a solid phase extraction followed by gas chromatography–tandem
mass spectrometry was developed for trace analysis of 32 compounds in water matrices, including estrogens
and several pesticides from different chemical families, some of them with endocrine disrupting
properties. Matrix standard calibration solutions were prepared by adding known amounts of the analytes
to a residue-free sample to compensate matrix-induced chromatographic response enhancement
observed for certain pesticides. Validation was done mainly according to the International Conference
on Harmonisation recommendations, as well as some European and American validation guidelines with
specifications for pesticides analysis and/or GC–MS methodology. As the assumption of homoscedasticity
was not met for analytical data, weighted least squares linear regression procedure was applied as a
simple and effective way to counteract the greater influence of the greater concentrations on the fitted
regression line, improving accuracy at the lower end of the calibration curve. The method was considered
validated for 31 compounds after consistent evaluation of the key analytical parameters: specificity,
linearity, limit of detection and quantification, range, precision, accuracy, extraction efficiency, stability
and robustness.
Description
Keywords
Endocrine disruptors Pesticides GC–MS Water Weighted linear regression schemes Validation
Citation
Publisher
Elsevier