Analysis of pesticide residues in soil: A review and comparison of methodologies

This work reviews recently developed methodologies for multiclass pesticide residue analysis in soil and evaluates them under the focus of Green Analytical Chemistry principles, cost and time. Different extraction, clean-up and determination techniques are highlighted. QuEChERS was found to be the dominant form of extraction reported, although extractions using pressurized fluid, ultrasound and simple solid-liquid partitioning are still widely employed. GC-MS and LC-MS remain the standard analytical techniques, with the latter becoming more prevalent due to its greater versatility in analysing different chemical classes of pesticide residues, namely poorly volatile compounds. A selection of twelve representative methods was compared using the analytical eco-scale and AGREE metrics, as well as in terms of instrumental and operational cost, and time. The analysis shows that the choice of reagents and other operational parameters are more important towards the greenness of a method than the extraction and determination techniques used, but cost and time are more dependent on the techniques themselves.