Analysis of melamine in milk powder by CZE using UV detection and hyphenation with ESI quadrupole/TOF MS detection.

An easy to employ method for the determination of melamine in milk powder samples using CZE with either UV or MS detection is presented. The separation capabilities of CZE allowed keeping sample preparation rather simple. Before analysis, milk powder samples were dissolved in water, de-fatted with dichloromethane and diluted with ACN to precipitate the protein, filtrated and injected without further pretreatment. The developed CZE method allowed the determination of melamine in milk powder down to a level of 0.50 mg/kg using UV detection and 0.25 mg/kg when ESI quadrupole/TOF MS was employed for detection.