Melamine made headlines in September 2008 because it was found to be the contaminant responsible for the deaths of several infants and making many more sick. Determination of trace melamine is very important. Therefore, in this work a novel, sensitive and reliable method was developed using differential pulse polarography. The most suitable buffer system was found to be Britton-Robinson (B-R) buffer, pH 11.2. The melamine peak in this medium appeared at about −50 mV, it responded well to standard additions and high reproducibility was obtained. The calibration graph was linear in the concentration range of melamine from 1.0 to 66.4 μM with a correlation coefficient of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were obtained as 0.3 and 1.0 μM, respectively. The current was characterized as being adsorption-controlled process. The proposed method was successfully applied to the determination of melamine in spiked milk and milk powder. The linear dynamic ranges observed for melamine concentration in milk and milk powder samples were between 1-58 and 10-57 μM, respectively. The sufficiently good recoveries and low standard deviations for the data reflect the high accuracy and precision of proposed differential pulse polarographic method.

Cyanuric acid is a suspected gastrointestinal or liver toxicant in humans. Therefore, determination of trace cyanuric acid is very important, in this work a novel, sensitive, and reliable method was developed using differential pulse polarography. Optimum conditions for analytical determination were found to be at a pH of 9.5, BrittonRobinson at a reduction potential of À105 mV. Experimental results indicate an excellent linear correlation between the peak current and the concentration in the range of cyanuric acid from 0.5 to 27.0 mM (0.06-3.5 mg mL À1 ) with a correlation coefficient of 0.997. The limit of detection and limit of quantification were obtained as 0.15 and 0.5 mM (0.02-0.06 mg mL À1 ), respectively. The proposed method was successfully applied to the determination of cyanuric acid in pool water and in spiked milk. Cyanuric acid level in swimming pool water was found as 2.54 AE 0.47 mg mL À1(19.7 AE 2.29 mM) in swimming pool water for N ¼ 4 and 95% confidence interval. The recoveries were found to be sufficient. Also, the standard deviation of the data was low which shows high accuracy and precision of proposed differential pulse polarographic method. The influences of some other commonly found inorganic salts on the determination of cyanuric acid were also examined. Some interfering species were eliminated using complexing agents, e.g., EDTA.

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