Direct determination of Cu and Zn in fruit juices and bovine milk by thermospray flame furnace atomic absorption spectrometry

In the present work, thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was employed for Cu and Zn determination in bovine milk and fruit juice samples without any pretreatment. TS-FF-AAS system was optimized and a sample volume of 300 mul was injected into the carrier stream (0.014 mol I-1 HNO3 at a flow rate of 0.4 ml min(-1)), and it was introduced into a hot Ni tube. The detection limits obtained for Cu and Zn in aqueous solution were 2.2 and 0.91 mug l(-1), respectively, and 3.2 mug l(-1) for Cu in a medium containing water-soluble tertiary amines. The relative standard deviations varied from 2.7 to 4.2% (n = 12). Sample preparation was carried out by simple dilution in water or in water-soluble tertiary amines medium. Accuracy was checked by performing addition-recovery experiments as well as by using reference materials (whole milk powder, non-fat milk powder, and infant formula). Recoveries varied from 97.7 to 105.3% for Cu and Zn. All results obtained for reference materials were in agreement with certified values at a 95% confidence level. (C) 2004 Elsevier B.V. All rights reserved.