Determination of lead in rice grains by solid sampling HR-CS GFAAS

Abstract

A study was performed for the determination of lead in rice grains directly by solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) without digesting sample. The effects of sample amount, pyrolysis/atomization temperatures on the determination of lead in rice were investigated and optimized using a certificated rice flour. The lead concentrations were determined applying 800 °C of pyrolysis and 1800 °C of atomization temperatures without modifier. LOD (N=10, 3σ) and characteristic mass were 2.3 μg kg(-1) and 8.1 pg, respectively. The certified lead value of a rice flour CRM was found in its uncertainity limits. The lead contents of various rice samples obtained from markets in Turkey were between 0.009 and 0.162 mg kg(-1) which are in acceptable range. The average lead concentrations in various rice grains taken from the same package were significantly different from each other.