Comparative studies by IR, Raman, and surface-enhanced Raman spectroscopy of azodicarbonamide, biurea and semicarbazide hydrochloride

• IR, Raman and SERS methods have been studied on azodicarbonamide, biurea, and semicarbazide hydrochloride.
• The molecular structure and assignment of these three molecules have been studied by DFT calculations.
• The limit of detection of this method being as low as 10 μg/mL (less than the standard regulation).

Azodicarbonamide is widely applied in the food industry as a new flour gluten fortifier in China, Canada, the United States, and some other countries, whose metabolites of biurea and semicarbazide hydrochloride are reaction products during baking. In this study, IR, Raman and surface-enhanced Raman scattering (SERS) spectra of azodicarbonamide, biurea, and semicarbazide hydrochloride have been studied, and vibrational bands have been assigned on the basis of density functional theory (DFT) calculations. The calculated Raman spectra were in good agreement with experimental Raman spectra. The SERS method coupled with active gold substrates has also been applied for detection of the three chemicals with pure water as solvent, with the limit of detection of this method being as low as 10 μg/mL (less than 45 μg/mL). These results showed that azodicarbonamide and its metabolites could be detected by the vibrational spectra technique, which might be applied as a powerful tool for the rapid detection on these species derived from agents added to flour.

Figure optionsDownload as PowerPoint slide