Selective determination of dopamine in the presence of ascorbic acid at an over-oxidized poly(N-acetylaniline) electrode

Abstract

An over-oxidized poly(N-acetylaniline) (PNAANI)/GCE was used to determine dopamine (DA) in a large excess of ascorbic acid (AA) by differential pulse voltammetry. A linear relation between I_p and DA concentration was found over the range 5.0 × 10⁻⁷ to 2.0 × 10⁻⁵ M. The detection limit was 1.68 × 10⁻⁸ M for S/N = 3 and 400 µM AA did not interfere with the DA determination. The high sensitivity was due to accumulation and selectivity was due to charge discrimination. The mechanism of selective determination of DA at over-oxidized PNAANI/GCE was also proposed.