title: Sulphate determination after its reduction to hydrogen sulphide and volatile separation by molecular absorption spectrometry.
abstract: A rapid spectrophotometric method for sulphate determination in a discontinuous mode is described. The method is based on sulphate reduction to hydrogen sulphide followed by its volatilization and absorption in an alkaline solution. The reduction is obtained when a sulphate sample is heated to 287 degrees C for 15 min, with a mixture of Fe(o)/KI and phosphoric acid. The resulting gas is swept by nitrogen flow into a 0.1 M sodium hydroxide solution and the absorbance of the sulphide ions is measured directly at 230 nm. The proposed method enabled us to determine 50-700 mug of total sulphate with a relative standard deviation of the order of 5%. The method has been applied for the determination of sulphates in liquid (mineral waters) and solid (gypsiferous soils) samples.
authors.forename: A
authors.initials: A
authors.lastname: Lopez Molinero
authors.forename: R
authors.initials: R
authors.lastname: Batlle
authors.forename: A
authors.initials: A
authors.lastname: Villareal
authors.forename: J R
authors.initials: JR
authors.lastname: Castillo