title: Optimization of microwave assisted digestion procedure for the determination of zinc, copper and nickel in tea samples employing flame atomic absorption spectrometry.
abstract: The present paper describes the development of a microwave assisted digestion procedure for the determination of zinc, copper and nickel in tea samples employing flame atomic absorption spectrometry (FAAS). The optimization step was performed using a full factorial design (2(3)) involving the factors: composition of the acid mixture (CMA), microwave power (MP) and radiation time (RT). The experiments of this factorial were carried out using a certified reference material of tea GBW 07605 furnished by National Research Centre for Certified Reference Materials, China, being the metal recoveries considered as response. The relative standard deviations of the method were found below 8% for the three elements. The procedure proposed was used for the determination of copper, zinc and nickel in several samples of tea from Turkey. For 10 tea samples analyzed, the concentration achieved for copper, zinc and nickel varied at 6.4-13.1, 7.0-16.5 and 3.1-5.7 (microg g(-1)), respectively.
authors.affiliation: Erciyes University, Faculty of Art and Science, Department of Chemistry, 38039-Kayseri, Turkey. soylak@erciyes.edu.tr
authors.forename: Mustafa
authors.initials: M
authors.lastname: Soylak
authors.forename: Mustafa
authors.initials: M
authors.lastname: Tuzen
authors.forename: Anderson Santos
authors.initials: AS
authors.lastname: Souza
authors.forename: Maria
authors.initials: M
authors.lastname: das Graças Andrade Korn
authors.forename: Sérgio Luis Costa
authors.initials: SL
authors.lastname: Ferreira
mesh_terms: D003300:Copper / Q000737:chemistry*; D006361:Heating; D008872:Microwaves; D009532:Nickel / Q000737:chemistry*; D009792:Oceans and Seas; D013054:Spectrophotometry, Atomic; D013662:Tea / Q000737:chemistry*; D014421:Turkey; D015032:Zinc / Q000737:chemistry*
chemical_list: D013662:Tea; D003300:Copper; D009532:Nickel; D015032:Zinc