Thin film hydride generation: determination of ultra-trace copper by flow injection in situ hydride trapping graphite furnace AAS

A novel system which significantly enhances copper hydride generation efficiency was used for the determination of trace copper by coupling a flow injection system to a graphite furnace for in situ collection of the analyte and subsequent AAS detection. A single device integrated the functions of hydride generator and gas liquid separator. Solutions of the sample containing 0.0005% (m/v) phenanthroline and 1% formic acid were merged with tetrahydroborate reductant to yield a thin film wetting a reaction surface from which product vapor was efficiently liberated and transported to the heated furnace. Optimum operating conditions provided for a generation/transport/collection efficiency of 8-12%. Interferences from common transition and noble metals were effectively eliminated. A limit of detection of 100 pg ml(-1) was obtained based on processing a 1 ml sample volume. A precision of better than 4% (RSD) at 1 ng ml(-1) was typical. The methodology was successfully applied to the determination of Cu in several NRCC natural water and biological tissue Certified Reference Materials.