Sono-cathodic stripping voltammetry of manganese at a polished boron-doped diamond electrode: application to the determination of manganese in instant tea

Abstract

Ultrasonically assisted cathodic stripping voltammetry at a boron-doped diamond electrode was developed for the detection of manganese. Differential-pulse voltammetry was used to give the analytical signal from a cathodic strip of electrodeposited MnO₂; linearity was observed from 10^–11 M to at least 3 × 10^–7 M, with 10^–1l M being the detection limit for a 2 min deposition. The procedure involves both ultrasonic–anodic deposition of MnO₂ and ultrasonic–cathodic stripping. This novel analytical tool is robust, reproducible, mercury free, oxygen insensitive and highly specific towards manganese. The differential-pulse sono-cathodic stripping voltammetric technique was used to determine successfully the manganese content of two instant tea samples, giving excellent agreement with independent AAS analyses.