Curtin Water Quality Research Centre, Curtin University, Kent Street, Bentley 6102, Perth, Australia.
J Chromatogr A. 2010 Sep 17;1217(38):5995-6001. doi: 10.1016/j.chroma.2010.07.051. Epub 2010 Jul 22.
Sulfide and polysulfides are strong nucleophiles and reducing agents that participate in many environmentally significant processes such as the formation of sulfide minerals and volatile organic sulfur compounds. Their presence in drinking water distribution systems are of particular concern and need to be assessed, since these species consume disinfectants and dissolved oxygen, react with metal ions to produce insoluble metal sulfides, and cause taste and odour problems. The analysis of sulfide and polysulfides in drinking water distribution systems is challenging due to their low concentrations, thermal instability and their susceptibility to undergo oxidation and disproportionation reactions. This paper reports on the development and optimisation of a rapid, simple, and sensitive method for the determination of sulfide and polysulfides in drinking water distribution systems. The method uses methyl iodide to derivatize sulfide and polysulfides into their corresponding dimethyl(poly)sulfides, which are then extracted using solid-phase microextraction in the headspace mode and analysed by gas chromatography-mass spectrometry. Good sensitivity was achieved for the analysis of dimethyl(poly)sulfides, with detection limits ranging from 50 to 240 ng L(-1). The method also demonstrated good precision (repeatability: 3-7%) and good linearity over two orders of magnitude. Matrix effects from raw drinking water containing organic carbon (3.8 mg L(-1)) and from sediment material from a drinking water distribution system were shown to have no interferences in the analysis of dimethyl(poly)sulfides. The method provides a rapid, robust, and reliable mean to analyse trace levels of sulfides and polysulfides in aqueous systems. The new method described here is more accessible and user-friendly than methods based on closed-loop stripping analysis, which have been traditionally used for the analysis of these compounds. The optimised method was used to analyse samples collected from various locations in a drinking water distribution system. Some of the samples were shown to contain inorganic polysulfides, and their presence was associated with high sediment density in the system and the absence of disinfectant residual in the bulk water.
硫化物和多硫化物是强亲核试剂和还原剂，参与许多具有重要环境意义的过程，如硫化物矿物和挥发性有机硫化合物的形成。它们在饮用水分配系统中的存在是特别值得关注的，需要进行评估，因为这些物质会消耗消毒剂和溶解氧，与金属离子反应生成不溶性金属硫化物，并导致味道和气味问题。由于其浓度低、热不稳定性以及易发生氧化和歧化反应，因此分析饮用水分配系统中的硫化物和多硫化物具有挑战性。本文报告了一种快速、简单、灵敏的饮用水分配系统中硫化物和多硫化物测定方法的开发和优化。该方法使用碘甲烷将硫化物和多硫化物衍生为相应的二甲基（多）硫化物，然后使用固相微萃取在顶空模式下提取，并用气相色谱-质谱法分析。二甲基（多）硫化物的分析灵敏度高，检测限范围为 50-240ng/L。该方法还表现出良好的精密度（重复性：3-7%）和两个数量级的良好线性度。从含有有机碳（3.8mg/L）的原水和饮用水分配系统沉积物材料中，发现基质效应不会对二甲基（多）硫化物的分析产生干扰。该方法为分析水相体系中的痕量硫化物和多硫化物提供了一种快速、稳健、可靠的手段。与传统用于分析这些化合物的闭路剥离分析方法相比，这里描述的新方法更易于使用。优化后的方法用于分析从饮用水分配系统的各个位置采集的样品。一些样品中含有无机多硫化物，其存在与系统中沉积物密度高和主体水中无消毒剂残留有关。
