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

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.