Spectrophotometric Determination of Trace Amount of Sulfide by Formation of Iodide and Its Solvent Extraction with Mehtylene Green

요오드이온 생성 및 Methylene Green과의 용매추출에 의한 미량 황이온의 분광광도법 정량

  • Kam, Sang-Kyu (Department of Marine Environmental Engineering, College of Ocean Sciences, Cheju National University) ;
  • Kim, Kyung-Youn (Department of Electronic Engineering, College of Engineering, Cheju National University)
  • 감상규 (제주대학교 해양과학대학 해양환경공학과) ;
  • 김경연 (제주대학교 공과대학 전자공학과)
  • Received : 1994.06.23
  • Published : 1994.09.25

Abstract

The iodide formed stoichiometrically for sulfide by its oxidation with iodate was extracted as an ion-pair with methylene green into 1,2-dichloroethane and the extract was measured spectrophotometrically at 656nm for the determination of sulfide. Hydrogen sulfide separated from the sample matrix was introduced into a solution containing pH 3.5 acetate buffer and iodate, in which the hydrogen sulfide was completely converted into iodide. A linear calibration graph was obtained over the range $3{\times}10^{-7}{\sim}1.2{\times}10^{-5}M$ sulfide($0.0096{\sim}0.384{\mu}g$ of $S^{2-}/ml$) and the detection limit was $0.0032{\mu}g/ml$. The apparent molar absorptivity and a correlation coefficient(r) were $6.7{\times}10^4L\;mole^{-1}\;cm^{-1}$ and 0.999, respectively. When applied to the stream water samples, the proposed method gave a relative standard deviation of 1.59% at $5{\times}10^{-6}M$ sulfide level.

Keywords

spectrophotometric determination of sulfide;the formation of iodide for sulfide by its oxidation with iodate;methylene green;separation as hydrogen sulfide from sample matrix;solvent extraction