Applicability of capillary electrophoresis with amperometric detection to study degradation of chlorophenols in contaminated soil

Details are presented for assembling an amperometric detector compatible with commercial capillary electrophoresis (CE) instruments. The detector assembled with a gold electrode achieves a sufficient sensitivity in analyzing liquid extracts to enable determination of pentachlorophenol (PCP) in soils at 35 mg/kg (PCP/soil). The CE system equipped with amperometric detection is used to study the oxidation of chlorophenols with ceric sulfate. The selected chlorophenols are completely oxidized by ceric sulfate in 5 min and the ceric sulfate can be recovered and reused. The same CE system is also applied for monitoring the photodegradation of PCP in contaminated soil, in the presence of titanium dioxide. Complete degradation of PCP, with no trace of electroactive products, is achieved in 7 h. This study demonstrates that capillary electrophoresis can be an important technique for monitoring processes of degradation and bioremediation.