In situ Preconcentration Method for Trace Dissolved Sulfide in Environmental Water Samples Using Solid-Phase Extraction Followed by Spectrophotometric Determination

摘要

A simple and rapid method for the in situ preconcentration of trace dissolved sulfide in environmental water samples has been developed based on solid-phase extraction using Sep-Pak C18 cartridges. Dissolved sulfide in water samples, which was taken into a graduated syringe to prevent the oxidation of sulfide by air, was reacted with N,N-dimethyl-p-phenylene-diamine sulfate and iron(III) chloride to be converted into Methylene Blue immediately after sample collection. The formed Methylene Blue was adsorbed on Sep-Pak C18, which was stable on Sep-Pak C18 for at least 30 d. The adsorbed Methylene Blue was eluted with a mixture of methanol and 0.01 M hydrochloric acid. The color intensity due to the Methylene Blue was measured at 659 nm. The proposed method is applicable to brackish and sea water samples as well as freshwater.