End-column electrochemical detection for aromatic amines with high performance capillary electrophoresis

Electrochemical detection of five species of aromatic amines at a carbon fi ber microdisk electrode after separation by capillary electrophoresis is de scribed. Under the optimum conditions, the detection limit for 3,4-dihydrox ybenzylamine, N,N-dimethylaniline, p-phenylenediamine, p-aminophenol and an iline sulfate was 0.9, 0.03, 0.075, 1.2 and 0.15 mu M (S/N = 3), respective ly. The linear response range was 5-1000, 0.1-500, 0.5-500, 5-500 and 1-200 mu M, respectively The effect of the electrode position and buffer pH on t he detection was also studied. This method is very simple, sensitive and st able for the detection of these compounds.