METHODS VALIDATION FOR DETERMINATION OF LEAD, CADMIUM AND TIN IN FRUIT JUICES BY MEANS OF GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY

摘要

The aim of this study was to validate graphite furnace atomic absorption spectrometry (GFAAS) methods for the determination of lead, cadmium and tin in fruit juices according to Commission Decision 2002/657/EC, UNI CEI EN ISO/IEC 17025/2005, Commission Regulation (EC) No 333/2007 and by taking into account Commission Regulation (EC) No 1881/2006. The main parameters evaluated in the validation process were: the detection and the quantification limits (LoD, LoQ), the recovery, the repeatability, the reproducibility, the linearity range and the standard measurement uncertainty. The statistical characteristics of the methods were assessed, and in particular the precision values calculated by the Horwitz equation. The results obtained for LoD and LoQ were, respectively: Pb - 5.48 and 18.26 μg/l; Cd - 1.77 and 5.90 μg/l; Sn - 0.3 and 1.0 mg/l, while for the recovery: Pb - 95.6%; Cd - 90.5%; Sn - 94.9%, and as for the repeatability: Pb - 9.3%; Cd - 1.65%; Sn - 0.28%. The expanded standard measurement uncertainty was estimated as follows: Pb - 17.5%; Cd - 14%; Sn - 24.4%. Also, the paper presents the results obtained by our laboratory by Food Analysis Assessment Scheme (FAPAS) Proficiency test 0795/2007 - Metallic Contaminants in Fruit Juice, organised by Central Science Laboratory, Sanf Hutton, York, United Kingdom.