Rapid And Easy Quantification Of Elemental Sulphur In Aqueous Samples From Biological Reactors: The Turbidimetric Method Revisited

Recent developments in wastewater treatment have led to a renewed interest to obtain elemental sulphur (S degrees) as a by-product from bioreactors. However, practical studies are limited by the gap of adequate analytical techniques for its determination. This paper provides a statistical study and matrix effect evaluation of an adapted spectrophotometric method for routine S degrees analyses in aqueous samples, based on a methodology previously described by Hart (1961). Four complex matrices were tested: domestic sewage and effluent samples from three different bioreactors. Tested performance criteria included linearity, matrix effect, limit of detection and quantification and S degrees recovery. Results were linear (R-2 = 0.99994) in the studied range (5 to 100 mg S degrees L-1) and no matrix effect was observed. The accuracy was based on recovery values that varied from 100% to 106%. The colloidal S degrees separation and extraction protocol was also considered suitable for aqueous samples, reaching more than 99.0% of S degrees recovery.