Determination of Melamine and Derivatives in Foods by Liquid Chromatography Coupled to Atmospheric Pressure Chemical Ionization Mass Spectrometry and Diode Array Detection

Abstract

Two liquid chromatographic methods based on atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) and diode array detection (DAD) are evaluated for the rapid determination of melamine (MEL) and structurally related compounds, including ammeline (AMN), ammelide (AMD), and cyanuric acid (CA) in foods. Both procedures used ion-exchange LC and isocratic elution. Samples were extracted by homogenization with acetonitrile/water/diethylamine. Specificity was demonstrated for LC-MS by the retention characteristics and MS spectra, by comparing with commercial standards. Specificity was only demonstrated in the case of LC-DAD for MEL and AMN, considering the retention characteristics and UV spectra. The recoveries obtained for spiked samples were satisfactory for all the analytes with LC-MS. The proposed procedure, LC-APCI-MS, was successfully applied to the analysis of different baby foods, including infant formula and breakfast cereal, and samples of rice flour, potato starch, soya drink, and coconut drink.

Keywords:

• Ammeline
• Cyanuric acid
• Foods
• Ion exchange LC-APCI-MS
• Melamine

Acknowledgments

The authors acknowledge the Comunidad Autónoma de la Región de Murcia (CARM, Fundación Séneca, Project 15217/PI/10) and the Spanish MICINN (Project CTQ2009-08267/BQU) for financial support. G. Férez acknowledges a fellowship from the Fundación Séneca (CARM).

Notes

Values into brackets correspond to ng g⁻¹