Detection of melamine in milk powder and human urine.

Detection of melamine has been developed by employing oxidized polycrystalline gold electrode (poly GE). The poly GE was directly utilized for the detection of melamine using differential pulse voltammetry (DPV) and impedimetry. Poly GE successfully showed the oxidation peak for melamine adsorption at 1.1 V is purely based on the detection of adsorption signals of melamine at the electrode surface. Furthermore, the melamine adsorbed poly GE surface has been studied using atomic force microscopy (AFM). Poly GE successfully detects the oxidation signals of melamine in the linear range of 0.05-1.31 ppm in laboratory samples. The proposed poly GE successfully detects the melamine signal (0.06-0.85 ppm) in tainted milk powder samples. It also exhibits two well-separated anodic oxidation peaks for urine and melamine in melamine-spiked human urine samples. Gas chromatography-mass spectrometry (GC-MS) was also employed for the successful detection of melamine in the above proposed real samples.