Abstract

GUERRERO DALLOS, Jairo Arturo  and  VELANDIA RODRIGUEZ, Nancy Yohanna. Comparison of two methodologies for the determination of pesticides residues in drinking water. Rev.Colomb.Quim. [online]. 2014, vol.43, n.1, pp.17-24. ISSN 0120-2804.  https://doi.org/10.15446/rev.colomb.quim.v43n1.50538.

A comparative study of two methodologies for the determination of pesticide residues in drinking water was performed in order to establish which of them is more suitable of a method of analysis. The assessed methodologies involved solid phase extraction using polymeric adsorbent LiChrolut ® EN and liquid-liquid extraction using n-hexane as the extraction solvent; its determination was performed by GC with µECD and NPD detectors. The study involved 50 pesticides, including different chemical families, such as organophosphates, organochlorines and pyrethroids among others. The detection capability was assessed by establishing the limits of detection and quantification, and the accuracy and precision performing recovery experiments. It was determined that the two methodologies have suitable detection regarding the maximum concentrations permitted by the Colombian regulations, except for monocrotophos insecticide, for which a limit of detection obtained was slightly above to the required value. The recovery experiments showed that all organochlorine and pyrethroid pesticides can be analyzed using liquid-liquid extraction, while the solid phase extraction is more suitable for the more polar pesticides such as organophosphates and azoles; It was determined that 22 compounds can be analyzed by either of the two methods, that is possible to analyze 36 of the 50 compounds evaluated by solid phase extraction, while using liquid liquid extraction 28 can be analyzed.

Keywords : Pesticides; drinking water; liquid-liquid extraction; solid phase extraction.

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