Separation of s-triazine herbicides and their metabolites by capillary zone electrophoresis as a function of pH

The effects of buffer pH on electrophoretic mobility of various s-triazines (chloro-, hydroxy-, methoxy- and thiomethyl-s-triazines) in light of their chemical properties have been studied. Good separation was achieved for each class of s-triazines as cations, except for the chlorotriazines, with buffer pH around the pK(a) of the herbicides, as well as at a pH of pK(a) - 2. Migration times were correlated with molecular masses (as a first approximation of molecular size and shape). Possible hydrophobic wall interactions were detected at acidic pH and low voltage, Separation of hydroxytriazine metabolites as anions could also be achieved at a high pH of around 8, The detection level calculated for most of these s-triazines was 0.05 mu g/ml of analyte in the injection solution.