Objective Capturing and detecting the lost H₂S component in the emitted flash gas during conventional decompression sampling towards pressurized sulfur-containing gas field water can realize the more accurate determination of its H₂S content, and provide data support for optimizing and upgrading the design and purification efficiency of H₂S treatment unit over flash gas.

Methods Considering the problem that the determination result of H₂S for gas field water after the decompression and balance treatment are obviously low, this work conducts the research from the aspects of pressurized liquid sampling and H₂S gas analysis to discuss the influences of parameters including sampling device, sampling method, analysis method, sample pretreatment, acid consumption and stripping time.

Results Isobaric sampling is realized, stripping time is 5 min, no pre-filtration treatment is required, deionized water is chosen as the desorption liquid, and the classical iodometry is used as the detection method for hydrogen sulfide.

Conclusions By comparing the determination Results of H₂S content upon actual samples under pressure and decompression conditions, it shows that this technology is more reliable for accurate determination of hydrogen sulfide content in pressurized sulfur-containing gas field water, and will also provide a promising strategy for determination of dissolved gas in other pressurized solutions.