Polarography, reductometry and spectrophotometry are the known analytical techniques used for the quantification of persulfate (PS) in water. Although acceptable to a certain extent, these methods did not satisfy environmental chemists seeking for rapid, reproducible and accurate measurements of PS upon application of ISCO or AOPs technologies. Accordingly, a novel spectroscopy/complexometry analytical technique is developed via the use of an HPLC coupled to a bypass capillary column and a DAD detector. Special HPLC configuration uses a concentrated KI solution as mobile phase to readily oxidize PS present in the sample. The reaction takes place inside the capillary column under high pressure facilitating the production of Iodine suspension (I2) yielding finally the Tri-Iodide anion (I3-) complex formation in the presence of an excess of I- absorbing at 352 nm and minimizing therefore interference with other organic contaminants. The method was validated by comparison to traditional PS quantification methods and tested on several environmental samples. The new method proved its superiority in terms time requirement, labor need, material consumption, sample volume and simplicity. It eliminates inconsistency present in other methods caused by the delay between the PS/I- reaction and I3- measurement. The LDR extends from 0.5 to 300 mM with a LOD of 0.25 mM and a LOQ of 0.5 mM. The method is successfully used to rapidly and automatically monitor PS concentration in different projects in our laboratory helping in the determination of the reaction stoichiometric efficiency of the oxidation reaction and the kinetics study.

Innovative and rapid method for the quantification of persulfate in environmental samples using customized HPLC system

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.