Speciation Analysis of Trace Arsenic, Mercury, Selenium and Antimony in Environmental and Biological Samples Based on Hyphenated Techniques

Abstract

In order to obtain a well understanding of the toxicity and ecological effects of trace elements in the environment, it is necessary to determine not only the total amount, but also their existing species. Speciation analysis has become increasingly important in making risk assessments of toxic elements since the toxicity and bioavailability strongly depend on their chemical forms. Effective separation of different species in combination with highly sensitive detectors to quantify these particular species is indispensable to meet this requirement. In this paper, we present the recent progresses on the speciation analysis of trace arsenic, mercury, selenium and antimony in environmental and biological samples with an emphasis on the separation and detection techniques, especially the recent applications of high performance liquid chromatography (HPLC) hyphenated to atomic spectrometry or mass spectrometry.

Keywords: antimony; arsenic; hyphenated technique; mercury; selenium; speciation analysis.

Figure 1

Representative chromatograms of As, Hg, Se, and Sb species. (a) As: each at 100 μg/L. Detected by HG-AFS after separated by a Hamilton PRP-X100 column (250 mm × 4.1 mm i.d., 10 μm) and eluted using 15 mM (NH₄)₂HPO₄ (pH 6.0) at 1.0 mL/min flow rate [127]; (b) Hg: each at 5.0 μg/L. Detected by ICP-MS after separated by two consecutive Zorbax SCX columns (12.5 mm × 4.6 mm i.d., 5 μm) and eluted by 2.0 mM thiourea (pH 2.0) at 1.5 mL/min flow rate [128]; (c) Se: Detected by ICP-MS after separated by a Dinoex IonPac AS11 anion exchange column (4 mm i.d. × 250 mm) and eluted using 10 mM NaHCO₃ with 2% acetonitrile (pH 11 adjusted with 20% NH₃) at 0.6 mL/min flow rate [129]; (d) Sb: 1 μg/L Sb(V), 2 μg/L Sb(III) and TMeSb. Detected by ICP-MS after separated by a Hamilton PRP-X100 column (250 × 4.1 mm i.d., 10 μm) and eluted using A: 20 mM EDTA + 2 mM KHP (pH 5.5), B: 20 mM + 2 mM KHP + 40 mM (NH₄)₂CO₃ + 1% (v/v) CH₃OH (pH 9.0) at 1.2 mL/min flow rate [123].