DETERMINATION OF ALUMINUM IN SERUM BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY WITH PRIOR SAMPLE PRETREATMENT BY MICROWAVE DIGESTION AND SOLID-PHASE EXTRACTION

A microwave-assisted digestion system enabling simultaneous treatment of thirty-six samples with oxidizing acidic media in double-closed ves sels was devised. Aluminum was subsequently separated from the digeste d solution through solid phase extraction by prior reacting with 8-qui nolinol and adsorbing onto the simple XAD-4 resin column. In the separ ated fraction, Al, being in a state free from matrix interferences, ca n be directly determined with electrothermal atomic absorption spectro metry (ETAAS) simply by an external calibration standard. With meticul ous control of analytical blank introduced in the sample pretreatment steps, a good performance of analytical accuracy and limit of detectio n can be achieved. The proposed method, featuring freedom from potenti al interference in ETAAS and relatively fast sample throughput, can co nveniently serve as a reference and/or an alternative method for the d irect ETAAS method commonly used for routine clinical purposes.