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HPLC DETERMINATION OF CYANURIC ACID IN SWIMMING POOL WATERS USING PHENYL AND CONFIRMATORY POROUS GRAPHITIC CARBON COLUMNS
Citation:
Cantu, R, O M. Evans, L J. Wymer, A P. Dufour, AND F K. Kawahara. HPLC DETERMINATION OF CYANURIC ACID IN SWIMMING POOL WATERS USING PHENYL AND CONFIRMATORY POROUS GRAPHITIC CARBON COLUMNS. Analytical Chemistry 73(14):3358-3364, (2001).
Impact/Purpose:
Develop a method to determine the volume of recreational water ingested by relating the quantity imbibed to the level of a chemical biomarker measured in urine.
Description:
The chlorinated salts of cyanuric acid have found an important role in recreational swimming pool waters across the United States. Upon application to pool water, they can (1) release disinfectant chlorine or (2) stabilize the free available chlorine by acting as chlorine reservoirs in the form of cyanuric acid, preventing the photolytic destruction of residual chlorine by sunlight. Recommended levels of the cyanuric acid stabilizer are in the 10-100 mg/L concentration range according to the National Swimming Pool Foundation (San Antonio, TX). Two isocratic HPLC methods with UV detection (213 nm) employing Phenyl and Porous Graphitic Carbon (PGC) columns and phosphate buffer eluents (pH 6.7 and pH 9.1, respectively) were developed to accurately measure cyanuric acid in swimming pools. The two methods showed fast separation and detection of the stabilizer in 4 (phenyl) and 8 (PGC) minutes. Both methods offered practical sensitivities with method detection limits of 0.07 (Phenyl) and 0.02 mg/L (PGC). Neither one of the two methods requires the use of sample cleanup cartridges. They exhibited chromatograms with excellent baseline stability enabling low level quantitaiton. Most important, the PGC column showed good ruggedness with a useful lifetime of five months and 500 sample analyses per column. Finally, the statistical analysis of the relative precisions of the two methods indicated equivalence at the 0.05 critical level. Eleven pool water samples were fortified with 4.8 to 50.0 mg/L of the stabilizer, and the averagre recovery was 99.8%.