Title: Detecting multiple adulterants in dry milk using Raman chemical imaging Authors
Submitted to: Proceedings of SPIE
Publication Type: Proceedings
Publication Acceptance Date: April 20, 2012
Publication Date: June 15, 2012
Citation: Qin, J., Chao, K., Kim, M.S. 2012. Detecting multiple adulterants in dry milk using Raman chemical imaging. Proceedings of SPIE. 8369:83690H. Technical Abstract: A Raman chemical imaging method was developed for detecting the presence of multiple chemical adulterants in dry milk powder. Four chemicals (ammonium sulfate, dicyandiamide, melamine, and urea) were added in equal concentrations, between 0.1% and 5.0%, to nonfat dry milk. An area of 25×25 mm2 for each powder mixture sample was imaged, with a spatial resolution of 0.25 mm, using a 785-nm laser Raman imaging system spanning the 102–2538 cm–1 range. Images were also acquired for the pure chemical and milk samples to provide reference spectra. Component spectra for the chemical adulterants were extracted by self-modeling mixture analysis (SMA) and could be identified using spectral information divergence values. SMA contribution images were used to create Raman chemical images that visualized the identification and distribution of the four types of adulterants in the milk powder.