Simultaneous determination of benzotriazole copper inhibitor and microbiocidal isothiazolinenones by high-performance liquid chromatography

• Published in: Journal of Chromatography A 1994-02, Vol.661 (1), p.245-248
• Main Authors: Iob, A., Al-Yousef, F., Tawabini, B.S., Mohammed, A.I., Abbas, N.M.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Other chromatographic methods
• ISSN: 0021-9673
• DOI: 10.1016/0021-9673(93)E0942-N

A high-performance liquid chromatographic (HPLC) procedure for the separation and determination of the components of a formulation that contained sodium benzotriazole (copper inhibitor), 2-methyl-4-isothiazoline-3-one and 5-chloro-2-methyl-4-isothiazoline-3-one (microbiocide mixture) was developed. This mixture is used to protect and maintain a large water-chilling plant in Saudi Arabia. A UV spectrophotometric method was tried unsuccessfully as both sodium benzotriazole and the isothiazolinones had λ max at 275 nm, so an HPLC method was sought. Optimum conditions were established using a Hewlett-Packard RP C 8 column to be methanol-water (40:60) containing 0.05 M KH 2PO 4 as the eluent at a flow-rate of 1 ml/min. The relative standard deviation of the method at the 95% confidence level was found to be 0.8, 0.7 and 2.4% for the respective components at concentration levels of 35, 115 and 50 mg/l, respectively.