Determination of Melamine by Differential Pulse Polarography/Application to Milk and Milk Powder

Abstract

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.

Lateral flow test strip based on colloidal selenium immunoassay for rapid detection of melamine in milk, milk powder, and animal feed

“…1,2 There have been several events of MEL being criminally added to milk, milk powder, and other food products in order to artificially elevate the apparent crude protein content by means of its high nitrogen content of 66.7%. 3 Excess MEL intake has led to serious health problems.…”

A Fluorescence-Based Chemical Sensor for Detection of Melamine in Aqueous Solutions

“…The relative change in fluorescence was linearly correlated with the concentration of melamine in the milk at the range of 25-380 ppm (exhibited in Figure 5B) with a limit of detection of 15.4 ppm. This is slightly above the acceptable concentration of melamine in food products, and lower than the LOD of recently reported methods (Table S1, Supplementary Materials) [25][26][27][28][29][30][31][32][33][34]. However, this process is simple and quick and can provide a quick screening method for dairy samples.…”

A new method for rapid and sensitive determination of cholic acid in gallbladder bile using voltammetric techniques

“…4b). The slope of 0.73 between the theoretical value of 0.5 (diffusion controlled) and 1.0 (adsorption controlled) is expressed for the mixed or mainly adsorption controlled electrode process [24,25].…”