Fast determination of lead and copper in dairy products by graphite furnace atomic absorption spectrometry

A rapid and direct procedure for determining lead and copper in dairy products by electrothermal atomic absorption spectrometry (ETAAS) is described. Samples are slurried in a medium containing 50% v/v hydrogen peroxide, 1% v/v nitric acid, 0.5% w/v dihydrogen phosphate, and 20% v/v ethanol and directly injected into the furnace with no previous mineralization. Calibration is performed with aqueous standards. Limits of determination were 0.4 and 2.4 ng/mL for copper and lead, respectively. The reliability of the procedure was checked by comparison with the acid mineralization procedure and by analyzing 3 certified reference milk samples.