Analysis of metals in marine sediments by microwave extraction and flame, hydride generation and cold vapour atomic-absorption spectrometry

A simple and fast metal extraction method that combines closed vessels and microwave heating for the simultaneous extraction of ten selected heavy met als (As, Cd, Co, Cr, Hg, Mn, Ni, Ph, Zn) from marine sediments is proposed. Digestion conditions, i.e. power and times microwave irradiation, reagent extractant, sample amount, were optimized to recover the potentially availa ble metallic fraction not bound in silicates. A nitric acid and two step mi crowave program was established. The resulting solutions were analyzed by f lame (FAAS) hydride generation (HG-AAS) and cold vapour (CV-AAS) atomic abs orption spectrometry. Quantifications were made using direct calibration wi th aqueous standards. The recoveries of the spiked samples investigated ran ged from 89 to 113%. The results obtained from analyzing the BCR certified reference sediment CRM 277 Estuarine Sediment were in good agreement with t he certified values (93-105%), except for low values for chromium (79%). Th e relative standard deviations for the determination of metals were less th an 4%. Finally, the technique designed herein was applied to sediment sampl es from La Coruna estuary, NW Spain.