Aluminium content in milk powders by inductively-coupled argon plasma--optical emission spectrometry

Forty-four brands of milk powders and simulated milk powders were analysed for aluminium content using Inductively Coupled Plasma Spectroscopy (ICP-OES) technique. The samples covered the full range of infant food items available in Singapore--full-cream milk formula, infant formula, fortified infant formula and milk-free soy protein formula. ICP-OES technique was employed for the analysis. Most samples analysed were found to contain less than 1 mg aluminium per kg powder. The highest aluminium content found was 15.0 mg aluminium per kg powder in a milk-free soy protein formula. The study found that ICP-OES is a convenient and accurate technique for trace metal analysis. However, considerable care needs to be exercised in the selection of emission lines of the metal under analysis to avoid error caused by emission from other metal present in the sample.