Direct determination of Fe and Zn in different components of cow milk by FAAS with a high performance nebulizer

摘要

Methods for the direct determination of iron and zinc in different components of cow milk (whole milk, non fat milk and whey milk) by flame atomic absorption spectrometry (FAAS) were performed using two nebulizers (nebulizer of platinum with a glass impact bead and a high performance nebulizer). The non fat milk and the whey milk were obtained by physical procedures (centrifugation and ultracentrifugation) in absence of chemical treatment. A limit of detection of 0.024 and 0.007 μg ml~(-1) for ironand zinc, respectively, were obtained by using a high performance nebulizer. The precision obtained varied between 1.4-4.0% and 0.4- 1.9% for iron and zinc, respectively. The accuracy of the methods was studied with the analysis of SRM-1549 and A-l 1 nonfat milk reference materials. The methods were applied to ten cow milk samples. Dates about the distribution of iron and zinc into the different components of cow milk were present.