Effective separation and sensitive determination of cyanuric acid, melamine and cyromazine in environmental water by reversed phase high-performance liquid chromatography.

A new method for the simultaneous determination of cyanuric acid (CA), melamine (MM) and cyromazine (CM) in different water samples was developed by using reversed phase high-performance liquid chromatography diode-array detection (RP-HPLC-DAD). The conditions of HPLC were investigated and optimized. A KROMASIL C18 column (250 x 4.6 mm ID, 5 microm) was used for the RP-HPLC using gradient elution with a mobile phase composed of 0.1 mM KH2PO4-K2HPO4 buffer solution (pH = 7.3) and methanol (75:25, v/v). The conditions for HPLC were investigated and optimized. Under optimal conditions, the linearity was satisfactory in the range of 0.04-10.00 microg/mL with a correlation coefficient of 0.999, and the method limits of detection (LODs) of the proposed method were 0.02 microg/mL for CA and CM, and 0.01 microg/mL for MM. The recoveries were: 96.0-116.0% with relative standard deviations (RSDs) of 0.9-5.7% for CA, 94.3-115.0% with RSDs of 1.5-5.3% for MM, and 91.0-112.0% with RSDs (n = 6) of 1.0-4.9% for CM. The proposed method can permit the detection of CA and CM at levels as low as 0.07 microg/mL and MM at levels as low as 0.03 microg/mL in environmental water samples.