Uses of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate as a good separation electrolyte for direct electrophoretic separation of quaternary ammonium herbicides.

This paper describes a new method for the direct separation of paraquat and diquat by CZE with ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate employed as reliable electrolyte. Several factors that affect the separation efficiency were investigated in detail. The experimental results indicated that the optimal running buffer consisted of 50 mM 1-butyl-3-methylimidazolium hexafluorophosphate and 10% ethanol (pH 5.0), applied voltage was 15 kV, and temperature was kept at 30 degrees C and baseline-separation was achieved within 18 min for the analytes. The proposed method would be very useful and have wide use to monitor the residual level of such pollutants when combined with high-sensitive detector and an excellent sample preconcentration technique with high enrichment factor in the future.