Rapid detection of trace amounts of Pb(II) and Cd(II) in water by fiber-in-tube preconcentration combined with anodic stripping voltammetry

A rapid and sensitive method was developed for the determination of trace amounts of Pb(II) and Cd(II) in aqueous solution using fiber-in-tube solid-phase microextraction (SPME) in combination with anodic stripping voltammetry (ASV). The main factors influencing the preconcentration and extraction of the metal ions, pH of the aqueous solution, filling mode, sample flow rate, eluent concentration, eluent volume, and eluent flow rate, were investigated. Under the optimized conditions, the process including preliminary enrichment by 100 times and ASV detection was completed within 20 min, and an adsorption percentage of >98% for Pb(II) and Cd(II) was obtained. The relative standard deviations at the limit of quantification (0.001 mu g L-1) were 8.13% (n = 6) and 6.01% (n = 6) for Pb(II) and Cd(II), respectively. The fiber-in-tube SPME was applied for the determination of Pb(II) and Cd(II) in drinking water, and the recoveries were 95.0-102.3% and 99.9-107.4%, respectively.