Abstract：
Total dissolved sulfide (TDS) plays multiple important roles in the aquatic environments. However, the determination of trace levels of TDS in natural waters is challenging because TDS is vulnerable to oxidation and volatilization. In this study, a fully automated flow injection analysis spectrophotometric system, incorporating a hollow fiber membrane contactor (HFMC) and a long path length liquid waveguide capillary cell, was fabricated to facilitate the on-site measurement of trace TDS in natural waters. The HFMC was used for matrix separation and analyte preconcentration. The measurement was based on the reaction of sulfide and N,N-dimethyl-p-phenylenediamine in the presence of FeCl3 under acidic conditions to yield methylene blue (MB). The proposed method was highly sensitive, with detection and quantification limits of 0.57 and 1.90 nmol L-1, respectively. The linear working range was from 1.90 to 150 nmol L-1, with a correlation coefficient of 0.9995. The repeatability, expressed as the relative standard deviation, was less than 0.86% (n = 15) and the recoveries varied from 76.2 ± 0.1% to 103.9 ± 0.6% (n = 3) for spiked samples. This method was applied to conduct a field analysis of TDS in a reservoir, giving results aligned with those obtained using a standard MB method. This work demonstrates that the new method for determining TDS was effective for both laboratory analysis and on-site measurement.
摘要：
总溶解硫化物（TDS）在水生环境中起着多种重要作用。然而,天然水域中痕量TDS的测定具有挑战性，因为TDS容易氧化和挥发。在这项研究中,全自动流动注射分析分光光度系统，结合中空纤维膜接触器（HFMC）和长路径长度的液体波导毛细管池，是为了方便自然水域中痕量TDS的现场测量而制作的。HFMC用于基质分离和分析物预浓缩。测量基于硫化物和N的反应，N-二甲基-对苯二胺在FeCl3存在下在酸性条件下产生亚甲基蓝(MB)。该方法灵敏度高,检测限和定量限分别为0.57和1.90nmolL-1。线性工作范围为1.90~150nmolL-1,相关系数为0.9995。可重复性,表示为相对标准偏差，小于0.86％（n=15），加标样品的回收率从76.2±0.1％到103.9±0.6％（n=3）不等。应用该方法对某储层TDS进行了现场分析,给出的结果与使用标准MB方法获得的结果一致。这项工作表明，测定TDS的新方法对实验室分析和现场测量均有效。
