Method of analysis of a selected group of pyrethroids in soil samples using off-line flow-through extraction and on-column direct large-volume injection in reversed phase high performance liquid chromatography.
An analytical method using flow-through extraction of a soil sample filled in a short HPLC column with methanol or methanol-water mixtures and large-volume injection in RP-HPLC has been developed for the simultaneous determination of residues of three pyrethroids--kadethrin, cypermethrin, and permethrin--from soil samples. The developed RP-HPLC method enables separation of four diastereoisomers of cypermethrin into three peaks and resolution of two diastereoisomers of permethrin. The UV photometric detection limits of direct on-column large-volume injection of 1.00 mL of extract were 30 ng/mL of kadethrin, 37 ng/mL of total content of cypermethrin, and 65 ng/mL of trans-permethrin, which corresponds to a pyrethroid soil content of around 0.3 mg/kg. Effects of extractant flow rate and optimal extractant volume on the percentage recovery of pyrethroids from Slovak soil samples were studied. Recovery studies were performed at 0.5- 5.0 microg/g fortification level of kadethrin and 1.0-2.5 microg/g fortification level of cypermethrin and permethrin in a soil sample. Recoveries ranged from 83 to 90% for kadethrin, from 87 to 94% for total cypermethrin, and from 85 to 98% for trans-permethrin. This work comprises a basic study aimed at elaboration of an RP-HPLC method of direct analysis of pyrethroids in a soil matrix at low concentration levels achieved by a "solid sample injection" in HPLC--on-line interfacing of analyte extraction, extract clean-up, and analysis.
Chalányová
Mária
M
Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia.
Paulechová
Martina
M
Hutta
Milan
M
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D026023:Permethrin / Q000032:analysis; D011722:Pyrethrins / Q000032:analysis*; D058428:Silica Gel; D012822:Silicon Dioxide; D012987:Soil / Q000032:analysis*
D011722:Pyrethrins; D012987:Soil; C017160:cypermethrin; D026023:Permethrin; C025638:kadethrin; D058428:Silica Gel; D012822:Silicon Dioxide