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 vessels was devised. Aluminum was subsequently separated from the digested solution through solid phase extraction by prior reacting with 8-quinolinol and adsorbing onto the simple XAD-4 resin column. In the separated fraction, Al, being in a state free from matrix interferences, can be directly determined with electrothermal atomic absorption spectrometry (ETAAS) simply by an external calibration standard. With meticulous control of analytical blank introduced in the sample pretreatment steps, a good performance of analytical accuracy and limit of detection can be achieved. The proposed method, featuring freedom from potential interference in ETAAS and relatively fast sample throughput, can conveniently serve as a reference and/or an alternative method for the direct ETAAS method commonly used for routine clinical purposes.