This method is for determining hydrogen sulfide and mercaptansulfur in hydrocarbons by potentiometric titration. Typical samplesinclude gasoline, naphtha, light cycle oils and similar distillatesthat are liquid at ambient temperature and pressure. The lowerlimit of quantitation is 0.2 mass-ppm mercaptan (as sulfur) and 1.0mass-ppm hydrogen sulfide (as sulfur).