A simple and efficient method using dual-cloud point extraction (dual-CPE) coupled with inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for the speciation of inorganic arsenic [As(III) and As(V)]. In first step of dual-CPE, As(III) formed a hydrophobic complex with ammonium pyrrolidine dithiocarbamate (As-APDC), and was subsequently entrapped by the Triton X-114 surfactant-rich phase at pH 5.0, whereas As(V) remained in the bulk supernatant. The surfactant-rich phase containing the As(III)-APDC complex was treated with a 2.0 mol L⁻¹ of nitric acid, and As(III) was back extracted into the aqueous phase at the second cloud point extraction stage before ICP-OES detection. The As(V) concentration was calculated by subtracting the concentration of As(III) from the total inorganic arsenic concentration after reducing As(V) to As(III) by thiourea. Different factors affecting the extraction of As(III) were investigated in detail. Under the optimum conditions, the detection limit for As(III) was 0.72 ng mL⁻¹ along with the relative standard deviation of 3.5% (C = 10.0 ng mL⁻¹, n = 5). The calibration curve was linear in the range of 2.0–50.0 ng mL⁻¹. This method was validated against the certified reference material (GSBZ 50004-88), and applied for the speciation of inorganic As(III) and As(V) in the spiked snow water sample.

开发了一种简单有效的方法，该方法使用双浊点萃取（dual-CPE）结合电感耦合等离子体发射光谱法（ICP-OES）来形成无机砷[As（III）和As（V）]。在双CPE的第一步中，As（III）与吡咯烷二硫代氨基甲酸铵（As-APDC）形成疏水复合物，随后在pH 5.0的条件下被富含Triton X-114表面活性剂的相截留，而As（V）保留在大量上清液中。用2.0 mol L ^-1处理含有As（III）-APDC配合物的富含表面活性剂的相然后在ICP-OES检测之前的第二个浊点萃取阶段将As（III）反萃取到水相中。在通过硫脲将As（V）还原为As（III）之后，通过从总无机砷浓度中减去As（III）的浓度来计算As（V）的浓度。详细研究了影响As（III）提取的不同因素。在最佳条件下，As（III）的检出限为0.72 ng mL ^-1，相对标准偏差为3.5％（C = 10.0 ng mL ^-1，n = 5）。校准曲线在2.0-50.0 ng mL ^-1范围内呈线性。该方法已通过认证参考材料（GSBZ 50004-88）的验证，并用于加标雪水样品中无机As（III）和As（V）的形态分析。