Validation of a quick and easy extraction method for the determination of emerging contaminants and pesticide residues in agricultural soils

Treated wastewater is currently used in the agricultural sector to solve the lack of availability of freshwater in many regions. However, reclaimed water can contain multiclass of organic contaminants. Therefore, the soil can become a reservoir of agricultural (e.g. pesticides) and urban (e.g. pharmaceuticals) contaminants. Consequently, the evaluation of this contamination process is necessary for assessing its potential human and environmental negative effects. Due to the low concentration levels, different chemical properties and the complexity of the matrix, an efficient sample preparation step for achieving adequate sensitivity and robust analysis in the soil is needed. The aim of this study was to develop a quick and easy extraction method based on a QuEChERS procedure for the determination of 27 organic contaminants in agricultural soil samples. The procedure was based on a salting-out extraction with acidified acetonitrile, followed by a dispersive solid-phase extraction (d-SPE). A liquid chromatography-tandem mass-spectrometry (LC-MS/MS) system was applied for the determination and quantification of the selected target analytes. The main benefits of this analytical approach are: • Reduction/elimination of majority of the interferences improving the sensitivity of the method. • Robust simultaneous determination of a multiclass of organic contaminants with very different physicochemical properties.