Determination of binary and ternary mixtures of pesticides in wetland waters by gas chromatography using partial least-squares analysis.
Partial least-squares (PLS) analysis was applied for the first time to ternary and binary mixtures of pesticides producing overlapping peaks in gas chromatograms. Several preprocessing algorithms for pretreatment of data were tested for optimization of the PLS models, and the most advantageous were used in each case. Three different mixtures of pesticides were resolved with satisfactory results: parathion-methyl, chlorpyrifos-methyl, and vinclozolin; parathion-ethyl, chlorpyrifos, and triadimefon; and endosulfan sulfate and carbophenothion. The proposed models were applied to the determination of 3 mixtures of pesticides at levels of 0.02-1.00 ng/mL in wetland water samples after a preconcentration step with C18 cartridges, with recoveries ranging from 82.7 to 117.4%. The reported method is sufficiently sensitive to measure pesticide residues at the maximum allowable concentrations given in the European Union Drinking Water Directive.
Gil García
M D
MD
University of Almería, Department of Analytical Chemistry, Spain.
Martínez Galera
M
M
Pablos Espada
M D
MD
Garrido Frenich
A
A
Martínez Vidal
J L
JL
D000465:Algorithms; D002138:Calibration; D002849:Chromatography, Gas; D004563:Electrochemistry; D007202:Indicators and Reagents; D016018:Least-Squares Analysis; D010575:Pesticides / Q000032:analysis*; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000032:analysis*
D007202:Indicators and Reagents; D010575:Pesticides; D012996:Solutions; D014874:Water Pollutants, Chemical