title: A colorimetric assay for the determination of polyhexamethylene biguanide in pool and spa water using nickel-nioxime.
abstract: A novel nickel-nioxime analytical method to measure polyhexamethylene biguanide (PHMB) in swimming pools and spas was developed. This method utilizes nickel(II) chloride and 1,2-cyclohexanedionedioxime (nioxime) chemistry. In the method, nickel ions bind and neutralize PHMB in the solution. Excess, un-reacted nickel ions react with nioxime and the resulting colored solution is measured at 550nm using a colorimetric assay. Currently, the colorimetric method to measure PHMB uses bromophenol blue (BPB). However, high levels of quaternary ammonium based algaecides and surfactant based products interfere with this colorimetric method. A time-consuming and expensive high-performance liquid chromatographic (HPLC) analysis can be used for samples with high levels of quaternary ammonium based algaecides or surfactants. The proposed nickel-nioxime detection method achieves comparable PHMB results to HPLC in about 5min and is a very economical and simple method to perform.
authors.affiliation: Arch Chemicals Inc., Treatment Products Research Center, 235 Cherry Lane, P.O. Box 231, New Castle, DE 19720, USA.
authors.forename: Touraj
authors.initials: T
authors.lastname: Rowhani
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Lagalante