Use of solid phase microextraction for the quantitative determination of herbicides in soil and water samples

An in-depth study of SPME optimization and application has been made, consi dering not only aqueous (surface water and groundwater samples) but also th e more complex soil samples. Seven herbicides widely used in the area of st udy have been selected including five triazine herbicides (atrazine, simazi ne, terbumeton, terbuthylazine, terbutryn), molinate, and bromacil. Lineari ty range was between 0.1 and 10 ng/mL and the repeatability below 10% when applying the optimized SPME procedure to water samples. Reproducibility was found to be lower than 20% at the 1 ng/mL level, and the limits of determi nation in environmental water samples using GC/MS (SIM mode) were well belo w 0.1 ng/mL(values ranging from 10 to 60 ng/L), Extraction of selected herb icides from soil was carried out by microwave-assisted solvent extraction u sing methanol in screw-capped vials, leading to recoveries over 80% in spik ed soil samples at the 5-200 ng/g level. SPME application over methanolic s oil extracts required a 10-fold dilution with distilled water. The recommen ded procedure was found to be fully applicable for quantitative determinati on of selected herbicides in soils containing lon organic matter content wi th coefficients of variation below or around 10% and limits of determinatio n ranging from 1 to 10 ng/g, Both procedures were applied to real-world sur face water and soil samples where several pesticides were detected includin g atrazine, simazine, terbuthylazine, and molinate.