Arsenic Detection Techniques and Their Drawbacks

The importance of arsenic detection techniques has received significant attention of researchers during recent years due to its carcinogenic effects on human health through drinking water even at low concentration. There are various arsenic detection techniques used in laboratory that have detection limit below 1μg/L viz., Hydride Generation Atomic Absorption Spectroscopy (HGAAS), Graphite Furnace Atomic Absorption (GFAA), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICPAES), Atomic Fluorescence Spectroscopy (AFS). This paper gives an overview of various technologies with the potential to measure and monitor arsenic in the aquatic environment. The relative effectiveness of arsenic concentration detection techniques which have been discussed in this paper is based on sensitivity of the method, reliability (or bias and precision) of the analytical results, specificity or selectivity of the method in the presence of interferences, operating range of the method, availability of equipment and trained personnel, quick analysis to permit routine use, and cost of analysis. The selection of a suitable technique among available techniques to detect arsenic in water samples is presented in this paper. The GFAAS technique is the preferred method in absence of overwhelming interferences whereas HGAAS is used when interferences of trace metal elements are present. ICPMS is considered to be more efficient with compared to all other methods mentioned above as it can determine the individual isotopes of each element and capable of multi elemental analysis, but it shows its limitations in detecting arsenic concentrations in presence of chloride. AFS technique is most efficient for detection of low arsenic concentration. Silver Di Ethyl Di Thio Carbamate (SDDC) method determines total inorganic arsenic when interferences are absent and sample contains no methyl arsenic compounds. When spectrometric methods are used in hyphenation with colorimetric methods, it becomes the most efficient technique for arsenic detection.