Baig Jameel A, Kazi Tasneem G, Arain Mohammad B, Shah Abdul Q, Kandhro Ghulam A, Afridi Hassan I, Khan Sumaira, Kolachi Nida F, Wadhwa Sham K
Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.
Anal Sci. 2011;27(4):439. doi: 10.2116/analsci.27.439.
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 (Al(2)O(3)) 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.
已开发出一种用于测定地下水样品中总砷、总无机砷和有机砷（As）形态的方法。通过吸附在氧化铝（Al₂O₃）上，将无机形态的As（Ⅲ，Ⅴ）与有机形态分离，而有机砷则被洗脱出来。保留的无机砷形态用0.2 M HCl洗脱。然后，洗脱液中的As（Ⅲ）和As（Ⅴ）分别与吡咯烷二硫代氨基甲酸铵（APDC）和钼酸盐形成络合物。接着，As（Ⅲ）-PDC和As（Ⅴ）-钼酸盐络合物被定量萃取到非离子表面活性剂Triton X-114中。总砷通过常规预浓缩程序测定。每种方法得到的溶液用带改性剂的电热原子吸收光谱法（ETAAS）测定。详细研究了影响分离和浊点萃取（CPE）的主要因素。As（Ⅲ）和As（Ⅴ）的检测限分别为0.04和0.20 μg L⁻¹，而定量限分别为As（Ⅲ）和As（Ⅴ）的0.13和0.33 μg L⁻¹。标准加入法证实了准确性。As（Ⅲ）和As（Ⅴ）的回收率在98 - 99%范围内。所提出的方法应用于从苏库尔地区不同区域采集的地下水样品。
