Methods for the determination of As, Cd, and Pb in potato slurry using multivariate optimization and graphite furnace atomic absorption spectrometry

Abstract

This study presents the development and validation of a method for the determination of arsenic (As), cadmium (Cd), and lead (Pb) in potato slurry samples using graphite furnace atomic absorption spectrometry (GFAAS) after multivariate optimization. The slurries were prepared by cryogenic grinding, sieving, and addition of 2% (v/v) nitric acid and 1% (v/v) hydrogenous peroxide up to a 2-mL volume. The slurries were kept homogeneous using air bubbling with an aquarium pump. Iridium (500 μg) and titanium were the best permanent modifiers for As, Cd, and Pb. Factorial design was used to obtain the best modifiers, pyrolysis and atomization temperatures for all analytes. After that a central composition design (CCD) was made, to obtain the best pyrolysis and atomization temperatures. The accuracy was evaluated by recovery tests over three different days (n=21) and the results varied from 97.4 to 102.8% for As, 102.3 to 105.2% for Pb, and 100.0 to 104.5% for Cd. The limits of detection and quantification were 0.08 and 0.26 μg g-1 for As, 3-77 and 12.6 ng g-1 for Cd, and 0.07 and 0.22 ng g-1 for Pb, respectively. For comparison, a certified reference material (NIST 1568a Rice Flour) was analyzed resulting in a value of 0.28 ± 0.06 μg g1 for As (certified value of 0.29 ± 0.03μg g-1) and 0.023 ± 0.001 μg g-1 for Cd (certified value of 0.022 ± 0.001 μg g-1). The method offers a simple sample preparation, resulting in adequate accuracy and precision, good sample output, and is very suitable for the quick and cost-effective analysis of potato samples.