The determination of aluminium in wool by atomic-absorption spectroscopy

Abstract

Atomic-absorption spectroscopy at 3092·7 A in a nitrous oxide-acetylene flame provides a simple and precise method for determining aluminium in wool. The sample is dissolved in constant-boiling hydrochloric acid, and the solution sprayed directly into the flame. The presence of hydrochloric acid partially suppresses the aluminium absorbance, whereas the amino-acids present in the wool hydrolysate enhance the absorbance. A linear calibration graph over the range 0 to 130 µg per ml is obtained from solutions of aluminium in constant-boiling hydrochloric acid containing the hydrolysed protein. Although the calibration graph has an accuracy of ±2 per cent., the heterogeneous nature of wool limits the accuracy of the analysis to ±3 per cent. The method, which has been applied successfully down to 0·02 per cent. of aluminium on wool, is equally suitable for other insoluble protein materials, such as hair and hide.