Oceans and Ecosystems, School of Environmental Sciences, University of Liverpool, 4 Brownlow Street, Liverpool, United Kingdom, L69 3GP.
Anal Chem. 2011 May 15;83(10):3848-56. doi: 10.1021/ac200314q. Epub 2011 Apr 15.
Stripping voltammetry is limited in acidic conditions to relatively high deposition potentials because of the interfering effects of the hydrogen produced at the working electrode. We report here a simple procedure to perform reliable and sensitive trace metal analysis in such conditions. Measurements are made at a gold microwire electrode. After applying a simple electrochemical conditioning procedure, hydrogen does not block the electrode, allowing reproducible analysis and smooth stripping signals to be obtained. Advantages of working inside the hydrogen wave are exemplified through the detection of the often considered electroinactive antimony(V). Sb(V) is detected in relatively low acidic conditions (pH ≤ 1) using low deposition potentials (≤-1.8 V). The detection limit is 5 pM (0.63 ppt), the lowest ever reported for an electroanalytical technique and one of the lowest analytical methods. The method is simple, robust, and free from the common arsenic interference due to selective electrochemical hydride generation of arsine over stibine during the deposition step. Analytical methods were optimized and tested on mineral, river, tap, and coastal seawater. Results favorably compare against Certified Reference Materials data (NASS-4 and SLRS-3) and ICPMS analysis. Deposition well below the hydrogen wave pushes the frontier of stripping voltammetry, and new analytical applications in this combined range of acidity and deposition potential are to be expected.
由于工作电极上产生的氢气的干扰作用，剥离伏安法在酸性条件下仅限于相对较高的沉积电位。我们在这里报告了一种简单的程序，可以在这种条件下进行可靠和灵敏的痕量金属分析。测量是在金微丝电极上进行的。在施加简单的电化学预处理程序后，氢不会阻塞电极，从而可以获得可重复的分析和光滑的剥离信号。通过检测通常被认为是非活性的锑(V)，说明了在氢波内工作的优点。在相对较低的酸性条件（pH≤1）下，使用低沉积电位（≤-1.8 V）可以检测到 Sb(V)。检测限为 5 pM（0.63 ppt），这是电分析技术中报道的最低检测限之一，也是最低的分析方法之一。该方法简单、稳健，并且由于在沉积步骤中通过电化学氢化物生成砷化氢选择性地除去了锑化氢，因此不存在常见的砷干扰。对矿物、河流、自来水和沿海海水进行了方法优化和测试。结果与认证参考物质数据（NASS-4 和 SLRS-3）和 ICPMS 分析相当。沉积电位远低于氢波，推动了剥离伏安法的前沿，预计在这种酸度和沉积电位的组合范围内会有新的分析应用。
