Quantitative detection of trace H2S based on ultraviolet differential optical absorption spectroscopy

Abstract

As an important decomposition component of SF6, H2S can provide an important information for the evaluation of insulation state of SF6 gas insulated equipment. Since H2S has obvious absorption in the ultraviolet (UV) range of 190∼230 nm, the UV absorption spectrum detection platform is established to realize its detection. In this paper, SF6 decomposition component detection platform based on UV spectroscopy was built, and the UV absorption spectrum of H2S was obtained. Since the UV absorption spectrum directly obtained by the instrument is susceptible to spectral scattering and high frequency noise, the detection sensitivity is low. Therefore, this paper uses the UV differential algorithm to obtain the UV absorption spectrum of H2S. After experimental tests, the R2 of the fitted line is as high as 0.999. Moreover, the method has good repeatability for detection of H2S, the results show that the absolute error does not exceed 0.2 μL/L. The noise is calculated by randomly collecting 30 sets background spectrum, and the detection limit is 0.590 μL/L when the signal-to-noise ratio is 1. A method for detecting H2S gas concentration based on UV differential absorption spectroscopy is proposed, which is suitable for on-line monitoring of trace H2S in the decomposition components of SF6 gas insulated equipment.