Development of an amperometric detector for the determination of phenolic compounds

Polyhistidine chemically modified electrode is shown to greatly improve the voltammetric waves and increase the current response of phenolic compounds (such as dopamine (DA), epinephrine (E) and catechol (CC)) for their cation-selective quality. When used as amperometric detector, the detection limits are 6 x 10(-9) mol/L for DA, 8 x 10(-9) mol/L for E and 2 x 10(-8) mol/L for CC. The modified electrode has also been used as electrochemical detector for capillary electrophoresis (CE) and the phenolic compounds were successfully separated and detected with high resolution. The electrode has a good stability; 80% of the original response was obtained after being used in CE for one month.