Speciation analysis of inorganic form of arsenic in ground water samples by hydride generation atomic absorption spectrometry with insitu trapping in graphite tube

Abstract

This paper presents the results of a study on the optimization of the determination of total arsenic and its species using the absorption atomic spectrometry method combined with hydride generation and in-situ concentration on the inner walls of the graphite tube. To ensure a maximum efficiency of the in-situ analyte concentration on the graphite tube walls, a palladium modifier subjected to preliminary thermal reduction was used. The limits of detection (3σ) were 0.019 ng/mL for total As and 0.031 ng/mL for As(III) at the preliminary analyte concentration for 60 s. The optimised procedure of the analyte concentration on the inner walls of the atomiser (graphite tube) was applied for determinations of arsenic in samples of ground water. The content of arsenic in the samples studied varied from 0.21 ng/mL to 0.80 ng/mL for As(III), and from 0.19 ng/mL to 1.24 ng/mL for As(V).

Atomic spectrometry update. Advances in atomic emission, absorption and fluorescence spectrometry, and related techniques

“…For an 8 ml sample, the frequency was 40 h À1 and the LOD was 0.1 mg l À1 . Niedzielski and Siepak reported 143 a similar procedure in which the arsine was trapped on the palladium-modified interior of a graphite furnace atomizer. The LOD was 0.02 mg l À1 .…”

Single Laboratory Validation of a Method for the Determination of Total Inorganic Arsenic by Hydride Generation Atomic Absorption Spectrometry

“…In general, inorganic arsenic compounds are much more toxic than organic ones, As(III) being reported to be 25-60 times more hazardous than As(V) (Li, Jia, and Wang 2006); arsenites about 10 times more toxic than arsenates, which are more toxic than the organic species of monomethyl-and dimethylarsenic acid; whereas, arsenobetaine are not toxic (Niedzielski and Siepak 2005). In natural and waste water, arsenic exists as As(III) and As(V), but also in low amounts as methyl-and dimethyl arsenic compounds.…”

The use of L-ascorbic acid in speciation of arsenic compounds in drinking water

“…Until now L-ascorbic acid was used as a chemical agent for arsenic preservation and stabilization in samples with arsenic concentrations 1mg/ml (30,45,46). L-ascorbic acid is also used as pre-reducing agent for the determination of total arsenic and total inorganic forms [As(III) and As(V)], in the presence of thiourea (28,31) or in combination with KI (33,34,36,38). In other cases, mixture of L-ascorbic acid and KI was used for reduction of inorganic As(V) and organic compound arsenic MMA by using cryogenic or HPLC separation (26,27,29,32,37).…”