Rapid Communications in Mass Spectrometry 2012-06-30

Detection of melamine in infant formula and grain powder by surface-assisted laser desorption/ionization mass spectrometry.

Yi-Ting Hsieh, Wen-Tsen Chen, Iva Tomalová, Jan Preisler, Huan-Tsung Chang

Index: Rapid Commun. Mass Spectrom. 26(12) , 1393-8, (2012)

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Abstract

We have developed a method for the determination of melamine (MEL), ammeline (AMN), and ammelide (AMD) by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using gold nanoparticles (Au NPs). The major peaks for MEL, AMN, and AMD at m/z 127.07, 128.05, and 129.04 are assigned to the [MEL + H](+), [AMN + H](+), and [AMD + H](+) ions. Because the three tested compounds adsorb weakly onto the surfaces of the Au NPs through Au-N bonding, they can be easily concentrated from complex samples by applying a simple trapping/centrifugation process. The SALDI-MS method provides limits of detection of 5, 10, and 300 nM for MEL, AMN, and AMD, respectively, at a signal-to-noise ratio of 3. The signal variation for 150-shot average spectra of the three analytes within the same spot was 15%, and the batch-to-batch variation was 20%. We have validated the practicality of this approach by the analysis of these three analytes in infant formula and grain powder. This simple and rapid SALDI-MS approach holds great potential for screening of MEL in foods.Copyright © 2012 John Wiley & Sons, Ltd.