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A new approach for the separation of sulfide from cement samples by chemically converting it to hydrogen sulfide and spectrophotometric determination was described. The method is based on converting the sulfide into hydrogen sulfide (H2S) gas using hydrochloric acid (HCl) and Tin (II) chloride dihydrate (SnCl2.2H2O) to reducing the ferric ions present in the cement samples that will prevent interfering with a recommended method, the liberated H2S gas was determined spectrophotometrically. This method provides a calculating the sulfide percentage in cement samples and using this percentage to background correction the percentage of the sulfate, which was calculated in an instrumental method, when using instrumental methods total sulfur will be determined, such as these instrumental methods, sulfide sulfur will be determined with the sulfate. The method was simple, rapid, sensitive, selective, accurate and the final orange-red solution was shown a maximum absorption at 510 nm. Beers law was obeyed percentage range of 0.04-0.4 S2-% with a molar absorptivity (1.12 × 104) L.mol−1.cm−1, and Sandell's sensitivity (5.34 × 10−2) µg.cm−2. The limit of detection (LOD) and limit of quantification (LOQ) were calculated as sulfide percentage and its values are 0.0081 S2-% and 0.0024 S2- %, respectively. [ABSTRACT FROM AUTHOR]

An Indirect spectrophotometric method for the determination of sulfate in the cement samples was described. The method is based on converting sulfate into hydrogen sulfide (H2S) gas using hydroiodic acid (HI) and sodium hypophosphite (NaH2PO2) then the amount of generated hydrogen sulfide gas was determined spectrophotometrically. The method was simple, rapid, sensitive, selective, accurate and the final orange-red solution was shown a maximum absorption at 510 nm. Beers law was obeyed in the sulfate percentage range of 0.5-5 SO3% with a molar absorptivity (1.03×104) L.mol-1.cm-1, and Sandell's sensitivity (5.76 x 10-2) μg.cm-2. Limit of detection (LOD) and limit of quantification (LOQ) are 0.27 SO3% and 0.08 SO3%, respectively. This method shows accurate results and reduced the time of sulfate estimating to approximately 1 hour. [ABSTRACT FROM AUTHOR]