Determination of Trace Copper in Natural Waters Using Flow Injection Chemiluminescence System with On-Line Solid-Phase Extraction

A novel flow injection chemiluminescence (FI-CL) system combined with on-line solid phase extraction (SPE) has been developed for the determination of trace copper in natural waters. The chemiluminescence (CL) is obtained by oxidation of novel rhodanine derivative by potassium permanganate in hydrochloric acid in the presence of copper. C₁₈-modified silica gel was packed into the glass tube to serve as SPE device. Extraction and preconcentration of the analytes were carried out using on-line SPE system and the selectivity of CL detection was improved. Under the optimum conditions, the calibration graph obtained by injecting copper solutions into the carrier stream is linear with CL intensity over the range of 1.0times10^-3-2.5 mugldrmL^-1 and the detection limit was 0.02 ngldrmL^-1 (s/n=3). The method was successfully applied to the determination of copper in natural waters. Compared with most of the other methods reported, the rapid and simple procedure proposed in the text offers higher sensitivity, wider linear range, and better stability.