Spectrophotometic flow injection determination of lead in port wine using in-line ion-exchange concentration

Abstract

A flow injection system with in-line ion exchange is proposed for the spectrophotometric determination of lead in Port wine. A Chelex-100 resin mini-column (200–400 mesh) is used for lead concentration, and the chromogenic reaction is based on the formation of a ternary complex between lead, Malachite Green and iodide. Forty-five digested wine samples can be run per hour (25–500 µg l^–1 Pb) and results are comparable to those obtained by ETAAS. Other features are the measurement precision (RSDs lower than 2.6%), a detection limit of 12 µg l^–1 and a sampling rate of 45 h^–1.