Adsorption, sample preservation, and cross‐contamination are the major impediments to the accurate and sensitive analysis of low‐level mercury samples. Common measures to deal with this issue are to use Teflon, quartz, or borosilicate glass bottles for sampling, standard solution and sample preservation with oxidative chemicals, to prepare standard solutions daily and to use dedicated glassware. This paper demonstrates that these measures are neither efficient nor effective. Two common laboratory sample containers (borosilicate volumetric glass flasks and polypropylene tubes) are investigated for the preparation and preservation of water samples and standard solutions of 0.2–1 µg L⁻¹ with 2% HNO₃. Mercury adsorption rates of 6–22% are observed within 30 min and after 48 days, the adsorption is greater than 98%. In stark contrast, no adsorption is found during a testing period of 560 days when the solutions are subject to potassium permanganate‐persulfate digestion. New glass flasks and polypropylene bottles are free of mercury contamination but reused flasks are a major source of mercury cross‐contamination. To minimize adsorption and cross‐contamination, standard solutions are treated by potassium permanganate‐persulfate or BrCl digestion, and each individual sample and standard solution should be stored and prepared in single‐use polypropylene bottle, without transference.

中文翻译：

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水中痕量汞的定量：解决吸附、样品保存和交叉污染问题。


吸附、样品保存和交叉污染是低含量汞样品准确、灵敏分析的主要障碍。解决这个问题的常见措施是使用聚四氟乙烯、石英或硼硅酸盐玻璃瓶来取样、标准溶液和用氧化化学品保存样品，每天配制标准溶液并使用专用玻璃器皿。本文表明这些措施既无效又无效。研究了两种常见的实验室样品容器（硼硅酸盐容量玻璃瓶和聚丙烯管）用于水样和含 2% HNO ₃的 0.2–1 µg L ^-1标准溶液的制备和保存。 30 分钟内观察到汞吸附率为 6-22%，48 天后吸附率大于 98%。与此形成鲜明对比的是，在 560 天的测试期间，当溶液经过高锰酸钾-过硫酸盐消化时，没有发现任何吸附。新的玻璃烧瓶和聚丙烯瓶没有汞污染，但重复使用的烧瓶是汞交叉污染的主要来源。为了最大限度地减少吸附和交叉污染，标准溶液经过高锰酸钾-过硫酸盐或氯化溴消解​​处理，每个单独的样品和标准溶液应在一次性聚丙烯瓶中储存和制备，不得转移。