The nature of the salt error in the Sn(II)-reduced molybdenum blue reaction for determination of dissolved reactive phosphorus in saline waters
Edward A Nagul, Ian D McKelvie, Spas D Kolev
Analytica Chimica Acta | ELSEVIER SCIENCE BV | Published : 2015
Sn(II) is a well-known reductant used in the formation of phosphomolybdenum blue for the determination of dissolved reactive phosphorus (DRP) in waters because it provides rapid and quantitative reduction. However, in saline waters, this method suffers from a salt error which causes a significant decrease in sensitivity. This phenomenon has never been adequately explained in the literature. The Murphy and Riley method, which uses Sb(III) and ascorbic acid for the reduction step, is preferred for DRP determination in saline waters because it is unaffected by salinity, but it exhibits a sensitivity approximately 30% lower than that when Sn(II) is used as the reductant without Cl(-) interferenc..View full abstract
E. Nagul is grateful for the award of an Australian Postgraduate Award. The authors wish to thank Dr. Stephen Best and Dr. Chris Ritchie for their helpful discussions.