title: Analysis of triazolopyrimidine herbicides in soils using field-enhanced sample injection-coelectroosmotic capillary electrophoresis combined with solid-phase extraction.
abstract: In this work, a combined methodology using off-line solid-phase extraction (SPE), on-line field-enhanced sample injection (FESI) and coelectroosmotic capillary electrophoresis with UV detection (CE-UV) is developed for the trace analysis of five triazolopyrimidine sulfonanilide pesticides (i.e., flumetsulam, florasulam, cloransulam-methyl, diclosulam and metosulam). An adequate background electrolyte (BGE) was obtained for the separation of these pesticides using hexadimethrine bromide (HDB) as electroosmotic flow (EOF) modifier. This BGE consisted of 0.00042% HDB, 11 mM formic acid, 16 mM ammonium carbonate and 2.5 mM alpha-CD solution at pH 7.6. The use of this running buffer together with the FESI preconcentration method provided limits of detection (LODs) in the low microg/L range (i.e., between 13.0 and 31.5 microg/L). The optimized FESI-CE-UV method was combined with off-line SPE using C(18) cartridges and applied to the determination of the selected group of pesticides in soil samples. Recovery percentages ranged between 50 and 84% in these samples with LODs between 18 and 34 microg/kg. This work shows the great possibilities of the combined use of SPE-FESI-CE-UV to improve CE sensitivity allowing the achievement of LODs similar to other analytical techniques as GC or HPLC.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Food Science, University of La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Hernández-Borges
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: García-Montelongo
authors.forename: Alejandro
authors.initials: A
authors.lastname: Cifuentes
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Rodríguez-Delgado
mesh_terms: D000813:Anilides / Q000032:analysis / Q000302:isolation & purification; D005591:Chemical Fractionation / Q000379:methods*; D004563:Electrochemistry; D004573:Electrolytes; D019075:Electrophoresis, Capillary / Q000379:methods*; D006540:Herbicides / Q000032:analysis* / Q000302:isolation & purification; D009862:Online Systems; D009995:Osmosis; D011743:Pyrimidines / Q000032:analysis* / Q000302:isolation & purification; D012989:Soil Pollutants / Q000032:analysis*; D014230:Triazoles / Q000032:analysis* / Q000302:isolation & purification; D014466:Ultraviolet Rays
chemical_list: D000813:Anilides; D004573:Electrolytes; D006540:Herbicides; D011743:Pyrimidines; D012989:Soil Pollutants; D014230:Triazoles