Abstract:

An atomic fluorescence spectrometric (AFS) method was developed for the determination of total arsenic in
wheat, vegetable and algae. Two sample pretreatments were proposed based on digestion with either HNO3-HClO4 or HNO3-
HClO4-H2SO4. Basically similar results were obtained by both sample pretreatments. Improved digestion of algae was
achieved by using H2SO4 due to its high boiling point, and the validity of this digestion method was confimed by proficiency
testing according to IMEP-112: Total and Inorganic Arsenic in Wheat, Vegetable Food and Algae. The chemical speciation
of inorganic arsenic was dominant in wheat and vegetable. Low boiling point acid was suitable for digestion of samples
with simple chemical speciation of arsenic and therefore enabled accurate determination of total arsenic. In the case of algae
samples, which are rich in organic arsenic, full conversion of organic arsenic to inorganic arsenic could only achieved by the
use of high boiling point acid for accurate determination.

Key words: atomic fluoresence spectrometry, wheat, vegetable, algae, pretreatment, total arsenic