SEPARATION OF NITROPHENOLS BY CAPILLARY ZONE ELECTROPHORESIS

Separation conditions suitable to a rapid resolution of a group of eig ht nitrophenols by capillary zone electrophoresis (CZE) were found. Re quired differences in their effective mobilities were achieved via hos t-guest complexation of beta-cyclodextrin combined with intermolecular interactions involved by polyvinylpyrrolidone. When both additives we re present in the carrier electrolyte at pH = 9.1 nitrophenols could b e separated in the column of a 300 mu m I.D. and 180 mm in the length within 8-9 minutes. It is shown that the column of such an I.D., provi ding enhanced sample load capacity, can operate with high separation e fficiencies as maintaining zone dispersions due to Joule heating on a tolerable level. CZE on-line coupled with isotachophoretic sample pret reatment is shown to provide the concentration Limits of detection at low ppb concentrations by using an on-column photometric detector oper ating at 254 and 405 nm detection wavelengths.