Quantification of chlorpyrifos in aqueous samples by liquid-liquid microextraction and gas chromatography using a µ-ecd detector

Abstract

The evaluation of contaminants present in the environment is a recurring theme at the international level, which is why it is imperative to develop new methodologies for the extraction of analytes from matrices such as surface water, with a low impact on the environment. Chlorpyrifos (CP) is an organophosphate compound widely used for pest control, toxic to living organisms, which can be mobilized from soils to different water sources. Dispersive liquid-liquid microextraction (DLLME) can be considered as a methodology with green analytical chemistry characteristics, due to its low solvent and time consumption. The objective of this work was to optimize DLLME for the analysis of CP in water samples. For the extraction, methanol was used as dispersing agent and CS2 as extracting agent, and five extraction times were evaluated: 5, 10, 15, 15, 20 and 25 min. The extracts were analyzed by gas chromatography with electron microcapture detector (GC-μECD). The results of the shaking time evaluation showed that, for the shaking times of 10 and 15 min, a CP recovery percentage of 108% and 88% was obtained, respectively, with a detection and quantification limit of 18.3 and 22.4 μg/L, respectively, and a precision expressed as relative standard deviation of less than 14.2%, which is acceptable for this type of extraction. It can be concluded that the DLLME methodology associated with GC-μECD is a suitable alternative for the quantification of CP in aqueous matrices with a low environmental impact.