FLOW-THROUGH MICROWAVE DIGESTION SYSTEM FOR THE DETERMINATION OF ALUMINUM IN SHELLFISH BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

A flow-injection system incorporating a microwave oven was constructed for the digestion of food samples for the subsequent determination of aluminium by electrothermal atomic absorption spectrometry. A volume or 100 mu l of sample slurry was simultaneously injected with 200 mu l of 3 mol l(-1) HNO3 and transferred into a PTFE reactor (coiled around an Erlenmeyer flask filled with water) located inside a microwave oven, The digested sample and flushing solution were collected in an autosampler cup. The sample was diluted 20-fold within the manifold. The performance of the procedure was evaluated by determining aluminium in an oyster tissue reference material. The recovery of aluminium was about 90%; however, the results for replicate analyses showed no significant differences. The proposed method was applied to the determination of aluminium in shellfish.