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本文采用偏硼酸锂熔样〔注〕,用含微量碘化钾的亚硫酸钠作还原剂,以阳极溶出伏安法测定了滑石中的微量砷,并使用改进的标准添加法扣除背景电流。方法的最低检出限可达0.04ppb,变动系数小于2.1％,回收率为96.5～106.5％。 1.仪器与电极 AD-Ⅱ极谱仪,LZ3-104函数记录仪金盘电极,Ag/AgCl参比电极(内参比液为1MKC1),铂丝辅助电极 2.实验方法和分析结果 (1)底液及酸度:比较砷(Ⅱ)在硝酸、盐酸、高氯酸及硫酸支持电解质中的溶出峰,确定硫酸为最佳。且当硫酸浓度大于0.8M后,溶出峰不再增高。
In this paper, lithium metaborate sample [Note], with a trace amount of potassium iodide sodium sulfite as a reducing agent, anodic stripping voltammetry determination of trace amounts of arsenic in talc, and the use of improved standard method to subtract the background current. The detection limit of the method was up to 0.04 ppb, the coefficient of variation was less than 2.1% and the recovery was 96.5 ~ 106.5%. 1. Instrument and electrode AD-Ⅱ polarographic instrument, LZ3-104 function recorder Gold plate electrode, Ag / AgCl reference electrode (internal reference solution 1MKC1), platinum wire auxiliary electrode 2. Experimental methods and analysis results (1) Bottom liquor and acidity: Arsenic (II) is compared with the dissolution peak of nitric acid, hydrochloric acid, perchloric acid and sulfuric acid supporting electrolyte to determine the best sulfuric acid. When the concentration of sulfuric acid is more than 0.8M, the dissolution peak no longer increases.