Detection of melamine in foods using terahertz time-domain spectroscopy.

The aim of this study was to investigate the feasibility of detecting melamine in foodstuffs using terahertz imaging. The terahertz (THz) spectra and images of melamine mixtures were obtained in the frequency range of 0.1-3 THz at room temperature using THz time-domain spectroscopy. Characteristic absorption peaks of melamine were found at 2, 2.26, and 2.6 THz, and these peaks showed the same frequencies in the different food matrices. At 2 THz, the THz images of melamine were dose-dependently distinguishable from those of food components with or without the packaging materials used. The calibration curve of melamine showed a regression coefficient (R(2)) of >0.913 and a detection limit of <13%. These results suggest that terahertz imaging has the potential to be used for the qualitative detection of melamine in food as a nondestructive analytical tool.

[1]  K. Kawase,et al.  Non-destructive terahertz imaging of illicit drugs using spectral fingerprints. , 2003, Optics express.

[2]  Yaochun Shen,et al.  Elimination of scattering effects in spectral measurement of granulated materials using terahertz pulsed spectroscopy , 2008 .

[3]  Y. C. Shen,et al.  Chemical mapping using reflection terahertz pulsed imaging , 2005 .

[4]  Charles A Schmuttenmaer,et al.  Terahertz spectroscopy of enantiopure and racemic polycrystalline valine. , 2011, Physical chemistry chemical physics : PCCP.

[5]  B. Fischer,et al.  The Christiansen effect in terahertz time-domain spectra of coarse-grained powders , 2008 .

[6]  Kodo Kawase,et al.  Component spatial pattern analysis of chemicals using terahertz spectroscopic imaging , 2003 .

[7]  P. Taday,et al.  Understanding the influence of polymorphism on phonon spectra: lattice dynamics calculations and terahertz spectroscopy of carbamazepine. , 2006, The journal of physical chemistry. B.

[8]  Robert E. Miles,et al.  Terahertz Time-Domain Spectroscopy for Material Characterization , 2007, Proceedings of the IEEE.

[9]  D. Abbott,et al.  Reduction of Scattering Effects in THz-TDS Signals , 2012, IEEE Photonics Technology Letters.

[10]  D. Tanner,et al.  Effects of Scattering on THz Spectra of Granular Solids , 2007 .

[11]  B. Fischer,et al.  Noncovalent intermolecular forces in polycrystalline and amorphous saccharides in the far infrared , 2003 .

[12]  Kirti Sharma,et al.  The melamine adulteration scandal , 2010, Food Security.