Deep-sea in situ determination of sulfide using a sensitized chemiluminescent terbium complex

A new chemiluminescence (CL) method based on the chemiluminescent reaction between sulfide and an acidic permanganate solution was used to quantify sulfide in seawater. A terbium-pipemidic acid complex was used as CL enhancer. The method was used to determine sulfide in the concentration range of 1-30 mu mol/L in artificial seawater samples. The limit of detection of the method was 21 nmol/L sulfide. The sensitivity of the CL method was eight times higher than that of the CL method reported previously. Br- ions, which are conservative ions, interfered with sulfide. We investigated the effects of salinity, water temperature, and interfering chemicals,such asheavy-metal ions and organic matter, on the performance of the CL method. In addition, sulfite-spiked natural seawater samples were analyzed. The results demonstrate that the CL method can be used to develop a deep-sea sulfide analyzer.

Automated summary

We developed a new chemiluminescence (CL) method for quantifying sulfide in seawater. A terbium-pipemidic acid complex was used as a CL enhancer. The method had a sensitivity eight times higher than previous methods and a limit of detection of 21 nmol/L sulfide. Interfering conservative ions, such as Br-, were investigated, as well as the effects of salinity, temperature, and interfering chemicals. The method was also validated using sulfite-spiked natural seawater samples.