Inorganic Arsenic Speciation in Groundwater Samples Using Electrothermal Atomic Spectrometry Following Selective Separation and Cloud Point Extraction

Abstract

A method has been developed for speciation of total, total inorganic and organic arsenic (As) species in groundwater samples. The inorganic species of As (III,V) were separated from organic forms by adsorbing on alumina (Al2O3) whereas the organic As was eluted out. The retained inorganic As species was eluted by 0.2 M HCl. Then eluent As III and As V were formed as complexes with ammonium pyrrolidinedithiocarbamate (APDC) and molybdate, respectively. Then As III -PDC and As V -molybdate complexes were quantitatively extracted into a non-ionic surfactant Triton X-114. The total As was determined by conventional preconcentration procedures. The resulting solutions of each method were determined by ETAAS with modifier. The main factors affecting the separation and cloud point extraction (CPE) were investigated in detail. The limits of detection values were found as 0.04 and 0.20 μg L -1 for As III and As V , respectively, whereas limits of quantification were observed as 0.13 and 0.33 μg L -1 for As III and As V , respectively. Standard addition method confirmed the accuracy. The recoveries of As III and As V were found in the range of 98 -99%. The proposed method was applied to groundwater samples collected from different areas of Sukkur district.

Evaluation of the fate of arsenic-contaminated groundwater at different aquifers of Thar coalfield Pakistan

“…This might be due to the less availability of carbonated and gypsum rocks (Brahman et al 2013b). However, EC and TDS have good correlation with all studied anions and cations (p<0.05), which might be the presence of minerals like calcite, fluorite, dolomite, and iron oxide (Baig et al 2011;Rafique et al 2008). …”

“…Then, the sample solutions were centrifuged, to separate the precipitates and make slurry by adding 5 ml of ultrapure water after subjected to ultrasonic bath for 2 min. Then, slurry with modifier was injected into a graphite tube by an autosampler (Baig et al 2011). The same procedure was applied for blank.…”

“…Then, the sample solutions were centrifuged. To surfactant-rich phase, added 0.5 mL of 0.1M HNO 3 in methanol, to reduce its viscosity before ETAAS determination (Baig et al , 2011Brahman et al 2013a). Then, 10 μl of sample solution with 10 μl of modifiers was injected into electrothermal atomizer.…”

Geostandards and Geoanalytical Research Bibliographic Review 2011

“…Environmental samples, such as NIST 1643, CASS‐4, NASS‐5 are of particular interest in the 2011 literature (e.g., Baig et al . , Böning and Schnetger ) and were used for water analyses. The bovine liver NIST SRM 1577a–c is also often used in environmental research, however for quality control of biological samples (e.g., Grotto et al .…”

Determination of Trace Zinc in Water, Soil and Rabbit Blood Samples Using Cloud Point Extraction Coupled With Ultraviolet-Visible Spectrophotometry

“…Moreover, compared with the classical liquid-liquid extraction method, CPE technique has become increasingly popular due to its high enrichment factor, high recovery, rapid phase separation, low cost, low consumption of organic solvents and the ability of combination with different detection. CPE combined with many modern analytical techniques such as atomic absorption spectrometry (AAS), spectrophotometry have been used to measure the concentration of metal elements in samples from environmental to human (Baig et al, 2011;Song et al, 2016). Spectrophotometric analytical methods and instruments have been widely applied in analytical chemistry for decades and offered many appealing characteristics, including simple instrumentation, rapid response times, and easy operation (Zarei, 2007).…”