Evaluation of flow injection sample to standard addition method for the inductively coupled plasma mass spectrometric determination of aluminium in biological tissues.

An on-line flow injection sample to standard addition method was developed for the determination of aluminium in biological tissues by inductively coupled plasma mass spectrometry. The sample concentration is calculated from two transient signals obtained from the injection of the blank and the sample, using a standard solution as carrier. A flow injection manifold for the on-line injection of both solutions was used and a three-step flow injection programme allowing the two transient signals to be obtained in the same measurement process was applied. A microwave nitric acid digestion procedure in closed vessels was used for sample dissolution, and scandium was added as an internal standard to control plasma fluctuations and to correct for ion signal instability. Tissue samples from healthy rat brain, kidney, liver, lung and spleen were analysed to find their aluminium concentrations. Complete recoveries from rat liver tissue spiked with aluminium concentrations in the 0.5-10.0 micrograms g-1 level were achieved. The detection limit (3 sigma) referred to the solid sample was of 10 ng g-1 and the precision (RSD) was better than 1%. The accuracy of the proposed method was tested by determining the aluminium contents in two NIST Standard Reference Materials: SRM 1577b Bovine Liver and SRM 8414 Bovine Muscle Powder).