Cloud Point Extraction for Electroanalysis: Anodic Stripping Voltammetry of Cadmium.
Cloud Point Extraction for Electroanalysis: Anodic Stripping Voltammetry of Cadmium.
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电分析的云点提取：镉的阳极剥离伏安法。
DOI：
10.1021/acs.analchem.5b00701
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发表时间：
2015-06-16
影响因子：
7.4
通讯作者：
Heineman WR
中科院分区：
文献类型：
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作者：
Rusinek CA;Bange A;Papautsky I;Heineman WR
浊点萃取（CPE）是一种成熟的技术，用于从水中预浓缩疏水物质，而不使用有机溶剂。随后的分析通常通过原子吸收光谱法（AAS）、紫外-可见光谱法或高效液相色谱法（HPLC）进行。然而，CPE的电分析方法，如溶出伏安法的适用性还没有报道。我们证明了使用CPE的电分析使用的测定镉（Cd 2+）的阳极溶出伏安法（ASV）作为一个代表性的例子。我们没有使用CPE中常用的螯合剂来形成疏水的、可提取的金属络合物，而是使用碘化物和硫酸来中和Cd 2+上的电荷以形成可提取的离子对。选择Triton X-114作为萃取的表面活性剂，因为其浊点温度接近室温（22-25° C）。比较了裸玻碳（GC）、铋涂层玻碳（Bi-GC）和汞涂层玻碳（Hg-GC）电极的CPE-ASV。镉的检测限为1.7 nM（0.2 ppb）的汞-GC电极。还研究了无CPE的ASV分析的比较，观察到检测限降低20倍（4.0 ppb）。该程序的自来水和河水样品的分析的适用性也得到了证明。这种简单、通用、环境友好和具有成本效益的提取方法可能适用于各种各样的过渡金属和有机化合物，这些化合物可以通过电分析方法进行检测。
Cloud point extraction (CPE) is a well-established technique for the pre-concentration of hydrophobic species from water without the use of organic solvents. Subsequent analysis is then typically performed via atomic absorption spectroscopy (AAS), UV-Vis spectroscopy, or high performance liquid chromatography (HPLC). However, the suitability of CPE for electroanalytical methods such as stripping voltammetry has not been reported. We demonstrate the use of CPE for electroanalysis using the determination of cadmium (Cd2+) by anodic stripping voltammetry (ASV) as a representative example. Rather than using the chelating agents which are commonly used in CPE to form a hydrophobic, extractable metal complex, we used iodide and sulfuric acid to neutralize the charge on Cd2+ to form an extractable ion pair. Triton X-114 was chosen as the surfactant for the extraction because its cloud point temperature is near room temperature (22–25° C). Bare glassy carbon (GC), bismuth-coated glassy carbon (Bi-GC), and mercury-coated glassy carbon (Hg-GC) electrodes were compared for the CPE-ASV. A detection limit for Cd2+ of 1.7 nM (0.2 ppb) was obtained with the Hg-GC electrode. Comparison of ASV analysis without CPE was also investigated and a 20x decrease (4.0 ppb) in the detection limit was observed. The suitability of this procedure for the analysis of tap and river water samples was also demonstrated. This simple, versatile, environmentally friendly and cost-effective extraction method is potentially applicable to a wide variety of transition metals and organic compounds that are amenable to detection by electroanalytical methods.