Absolute determination method for trace quantities of enantiomer of glufosinate by gamma-cyclodextrin modified capillary zone electrophoresis combined with solid-phase extraction and on-capillary concentration.
A highly sensitive and accurate determination method for trace quantities of enantiomers of glufosinate (D,L-GLUF), a phosphorus-containing amino acid-type herbicide, has been studied. The present method is based on the change in the mole ratio of the enantiomeric isomers after spiking of a known amount of an isomer (L-GLUF). The chiral separation and detection were made by gamma-cyclodextrin modified capillary zone electrophoresis (gamma-CD-CZE) with fluorescence detection. Solid-phase extraction of D,L-GLUF with titania was investigated as the pre-separation method to eliminate coexisting materials such as inorganic salts and organic compounds in river water. A separated D,L-GLUF was labeled with dansyl chloride and subjected to the on-capillary concentration using large-volume sample stacking (LVSS) before gamma-CD-CZE. The detection limit of the present method was as low as 2.0 x 10(-9) M. The present method was successfully applied to a model sample containing 2.0 x 10(-7) M D,L-GLUF in river water. It was confirmed that trace quantities of D-and L-GLUF in environmental samples can be accurately determined without any calibration curves and comparison standards.
Asami
Takayuki
T
Department of Environmental Sciences, Faculty of Science, Ibaraki University, Japan.
Imura
Hisanori
H
D000613:Aminobutyrates / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006540:Herbicides / Q000032:analysis; D008722:Methods; D013237:Stereoisomerism; D014873:Water Pollutants / Q000032:analysis; D047408:gamma-Cyclodextrins
D000613:Aminobutyrates; D006540:Herbicides; D014873:Water Pollutants; D047408:gamma-Cyclodextrins; C003121:phosphinothricin