Electrothermal atomic absorption spectrometric determination of molybdenum, aluminium, chromium and manganese in milk

Procedures for the direct determination of manganese, aluminium, chromium and molybdenum in cowʹs milk, infant formula and human milk samples by electrothermal atomic absorption spectrometry with no sample pre-treatment are discussed. The powdered samples are suspended in a medium containing ethanol, nitric acid and hydrogen peroxide and directly introduced into the electrothermal atomizer. In the case of molybdenum, lactalbumin is incorporated in the suspension medium. Liquid milk samples are diluted with the suspension medium. Calibration is carried out using aqueous standards. The reliability of the procedures is checked both by comparing the results with those found after a conventional mineralization-based procedure and by analyzing certified reference materials.