title: On-line flow-through extraction-preconcentration-large volume injection-RP LC for trace determination of pyrethroids in Slovak soil.
abstract: A rapid micro-analytical multiresidue method was developed for analysis of pyrethroids (kadethrin K, cypermethrin C and permethrin P) in soil micro-sample (200 mg). It uses on-line flow-through extraction of soil micro-samples (packed into a short glass column) with a methanol-aqueous citric acid buffer mixture, successive on-line SPE preconcentration of analytes from the extract and on-line RP-HPLC analysis with UV photometric detection. The separation of pyrethroids is performed on a Purospher RP-18e column with methanol/water as mobile phase. Effects of sorbent placed at the bottom of a short column holding the soil sample and different kinds of on-line SPE columns were tested. Besides, the influence of volume of the effluent on the pyrethroids recovery was also studied. Calibration curves were linear over the range assayed from 0.01 to 0.2 microg/mL with correlation coefficients of linear regression (least-squares method) in the range 0.998-0.999. Recovery studies were carried out at 0.25-1.00 microg/g dry soil fortification level and obtained recoveries were for K 81-84%, C 56-59% and for P 58-63%. Achieved LOD (confidence band) of studied pyrethroids were for large-volume injection (1 mL) 4.5 ng K, 3.7 ng C, 3.6 ng P or 27 ng/g K, 32 ng/g C and 29 ng/g P in dry soil "solid sampling HPLC".
authors.affiliation: Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia.
authors.forename: Mária
authors.initials: M
authors.lastname: Chalányová
authors.forename: Milan
authors.initials: M
authors.lastname: Hutta
authors.forename: Martin
authors.initials: M
authors.lastname: Pagác