Rapid determination of mercury in environmental materials using on-line microwave digestion and atomic fluorescence spectrometry

A procedure for on-line microwave digestion and determination of mercury in environmental materials by atomic fluorescence spectrometry has been developed. The method is based on the direct injection of slurried samples (acidified) into a carrier stream of hydrochloric acid. Microwave digestion in a Teflon coil (4 m) permits, in only 50 s, the quantitative extraction of Hg from the solid samples. In combination with atomic fluorescence detection the on-line digestion/procedure permits the determination of mercury with a throughput of 15 samples per hour. Based on a sample injection volume of 400 μl, precision was 0.5–1.5% R.S.D. and the limit of detection was 0.09 ng g−1. Application to a range of certified environmental reference materials was demonstrated.