title: Automatic determination of nickel in foods by flame atomic absorption spectrometry.
abstract: A new sensitive and low cost flow injection method that combines acid extraction, preconcentration and flame atomic absorption spectrometric determination of nickel in food samples at μg/g levels is described. The dynamic acid extraction step was carried out by using a continuous ultrasound-assisted extraction system. The acid extract was preconcentrated on-line on a minicolumn packed with a chelating resin (Serdolit Che, with iminodiacetic groups) and nickel was eluted with diluted hydrochloric acid, being continuously monitored by flame atomic absorption spectrometry. An experimental design (Plackett-Burman 2(6)×3/16) is used to optimise the methodology proposed. The method allowed a total sampling frequency of 13-28 samples per hour. Good precision of the whole procedure (1.9-3.6% expressed as relative standard deviation) and a detection limit of 0.12μg/g, for 60mg of sample were achieved. The method was successfully applied to the determination of trace amounts of nickel in food samples.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, 15782-Santiago de Compostela, Spain. Electronic address: qncayebi@usc.es.
authors.forename: M C
authors.initials: MC
authors.lastname: Yebra
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, 15782-Santiago de Compostela, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Cancela
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, 15782-Santiago de Compostela, Spain.
authors.forename: R M
authors.initials: RM
authors.lastname: Cespón
keywords: Flow injection analysis; Food analysis; Minicolumn preconcentration; Nickel; Ultrasound-assisted acid extraction