Ultrasound-Assisted Digestion Using Flow Injection/Stopped-Flow Manifold and On-line Preconcentration for Urinary Nickel Determination by Flame Atomic Absorption Spectrometry

This work deals with nickel determination in urine samples using ultrasound energy for sample preparation. It is shown that this sample digestion procedure is a fast and simple methodology based on,in on-line procedure exploiting the stopped-flow mode. A minicolumn device filled with a commercial chelating resin (Chelite P) is inserted into the on-line manifold for trace nickel preconcentration prior to determination by flame atomic absorption spectrometry. The efficiency of the on-line total digestion-preconcentration process was studied in the mu g L-1 range, obtaining quantitative recoveries with good precision (< 5%). The limit of detection (3 sigma) was 0.6 mu g L-1 and the precision (RSD) was between 1.7-4.4%. The proposed method was applied for the determination of nickel in urine samples.