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Determination of lead in dietary supplements by high-resolution continuum-source graphite furnace atomic absorption spectrometry with direct solid sampling

Leal, Gabriela Camera, Mattiazzi, Patricia, Rovasi, Franciele, Molin, Thaís Dal, Bohrer, Denise, do Nascimento, Paulo Cícero, de Carvalho, Leandro M., Viana, Carine
Subtropical plant science 2020 v.86 pp. 103360
atomic absorption spectrometry, detection limit, dietary supplements, lead, magnesium, nitrates, zirconium
A method has been developed for the determination of lead (Pb) in dietary supplements using direct solid sampling and high-resolution continuum source graphite furnace atomic absorption spectrometry. The lead concentration was determined in 74 food supplements. The zirconium (Zr) coated platform, and chemical modifiers [Pd(NO₃)₂ and Mg(NO₃)₂] were applied. Mass aliquots between 0.8 and 1.0 mg were weighed and directly inserted into the graphite furnace. The precision (expressed as RSD) was lower than 5%, and a detection limit of 2.16 pg was obtained at the 283.306 nm resonance line. The limit of quantification was 7.2 pg. The Pb recuperation in the standard reference material, Bitter Orange-Containing Solid Oral Form NIST SRM 3260, was 116% of the certified value. The contents of Pb in the dietary supplement samples varied in the 0.04–25.3 μg/day range. Two samples had results above that allowed by American Pharmacopoeia for inorganic analysis in food supplements.