title: Direct determination of Cu and Zn in fruit juices and bovine milk by thermospray flame furnace atomic absorption spectrometry.
abstract: 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 300mul was injected into the carrier stream (0.014moll(-1) HNO(3) at a flow rate of 0.4mlmin(-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 0.91mugl(-1), respectively, and 3.2mugl(-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.
authors.affiliation: Grupo de Análise Instrumental Aplicada, Departamento de Quimica, Universidade Federal de São Carlos, P.O. Box 676, 13560-970 São Carlos, SP, Brazil.
authors.forename: Clésia C
authors.initials: CC
authors.lastname: Nascentes
authors.forename: Marco A Z
authors.initials: MA
authors.lastname: Arruda
authors.forename: Ana Rita A
authors.initials: AR
authors.lastname: Nogueira
authors.forename: Joaquim A
authors.initials: JA
authors.lastname: Nóbrega