Simultaneous determination of cyromazine, melamine and their biodegradation products by ion-pair high-performance liquid chromatography

An ion-pair high-performance liquid chromatography with ultraviolet detection method for the determination of cyromazine, melamine and its biodegradation products (ammeline, ammelide, cyanuric acid and biuret) was developed. C18 column was utilised to separate the six analytes with a mobile phase consisting of perchloric acid-ammonia solution and acetonitrile, under gradient elution and variable flow rate. The detection wavelengths were 205nm for cyanuric acid and biuret and 222nm for cyromazine, melamine, ammeline and ammelide. For analysis of sediment samples, the extraction solution containing acetonitrile, ammonia and water (80:10:10 by volume) was used to extract the analytes from sediment matrix. Using the extraction method for the spiked sediment sample, high linearity of matrix-matched standard curve could be obtained for the six analytes. The method detection limit was 0.1 mu gg(-1) for melamine and cyromazine, 0.2 mu gg(-1) for ammeline and ammelide, 1.2 mu gg(-1) for cyanuric acid and 1.0 mu gg(-1) for biuret in sediment matrix. The recoveries of these compounds were 70.1-98.3% and the relative standard deviations were 0.5-4.4%. Finally, the proposed method was successfully applied to the analysis of the sediment sample near the wastewater outlet of a melamine-producing factory.