On-Site Measurement of Trace-Level Sulfide in Natural Waters by Vapor Generation and Microchannel Collection

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• 作者：Kei Toda ; Haruka Kuwahara ; Shin-Ichi Ohira
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：July 1, 2011
• 年：2011
• 卷：45
• 期：13
• 页码：5622-5628
• 全文大小：944K
• 年卷期：v.45,no.13(July 1, 2011)
• ISSN：1520-5851

文摘

Aqueous sulfide plays an important role in the environment even at low concentrations. However, it is unstable, which means field samples cannot be transported to the laboratory for analysis without fixation. In this work, a novel method was developed to determine trace levels of sulfide on site. This method is based on vapor generation and collection in a special microchannel device followed by fluorescence measurement (VG-渭GAS). The microchannel scrubber gave a high enrichment factor, and a high sensitivity was achieved, which allowed measurement of nanomolar (nM) levels of sulfide. The theoretical approach to vapor generation for several compounds is discussed to evaluate the applicability of the method to these analytes, and compounds having a low Henry鈥檚 law constant (<1 M atm^鈥?) are suitable to measure by VG-渭GAS. Under optimized conditions, concentrations of 1.0鈥?00 nM of sulfide could be measured. The sulfide contents of hot spring, aquarium, pond, and seawater were successfully measured by this method. Nanomolar levels of sulfide could be measured on site without loss of analyte, and results were obtained instantly in the field, both of which are advantageous for effective field surveys. The method was also applied to field measurements of aqueous sulfide in the Ariake Sea and Lake Baikal.