Abstract: The concentration of a gas such as hydrogen sulfide in a liquid such as crude oil or other hydrocarbon liquid is measured by conducting a flowstream of the liquid through a jet or eductor type pump for mixing a recirculating vapor stream with the liquid, separating the liquid and the vapor stream in a separator to provide equilibrium conditions between the vapor and the liquid and withdrawing the vapor flowstream for recirculation and remixing with the liquid flowstream while measuring the concentration of the gas in the vapor flowstream. A known flow rate of the gas is added to the combined liquid and recirculating vapor flowstream and the incremental change in concentration of the gas in the recirculating vapor flowstream is measured to determine the concentration of the gas in the liquid flowstream initially.

Abstract: The invention relates to a method and reagent for the determination of peracids. The method is characterized in that the sample solution is mixed with a chromogen, an iodide and, where appropriate, a buffer-containing reagent, and the color reaction is evaluated, e.g., visually or by spectrophotometry.