http://www.nytimes.com/2009/06/09/science/09obtaint.html

New York Times June 8, 2009

"Last year, some 300,000 infants in China were sickened, and at least 6 died, after consuming infant formula that had been deliberately adulterated with the chemical melamine.

"The scandal, and previous contamination incidents involving pet food and other products, led the United States Food and Drug Administration to test food ingredients for the presence of melamine (which can make a food seem as if it has more protein than it does).

"The test the F.D.A. uses for infant formula, a liquid chromatography-mass spectrometry technique, is time-consuming. So several research groups have been looking for quicker and less elaborate methods to detect melamine in powdered formula.

"A group at Purdue University is reporting in The Journal of Agricultural and Food Chemistry that they have successfully used infrared spectroscopy for the task. Lisa J. Mauer and colleagues used several variations of the technique, which detects characteristic frequency-absorption patterns when light at infrared wavelengths is sent through a sample.

"All were able to detect melamine down to the threshold set by the F.D.A., one part per million, and quickly — the tests require little sample preparation beyond putting some powder into a vial, and results are obtained within a few minutes."

Bump:

http://pubs.acs.org/doi/abs/10.1021/jf900587m
Melamine Detection in Infant Formula Powder Using Near- and Mid-Infrared Spectroscopy

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Lisa J. Mauer*, Alona A. Chernyshova, Ashley Hiatt, Amanda Deering and Reeta Davis
Department of Food Science, Purdue University, 745 Agriculture Mall Drive, West Lafayette, Indiana 47907
J. Agric. Food Chem., 2009, 57 (10), pp 3974–3980
DOI: 10.1021/jf900587m
Publication Date (Web): April 22, 2009
Copyright © 2009 American Chemical Society
*Corresponding author [e-mail mauerl@purdue.edu; telephone (765) 494-9111; fax (765) 494-7953].
Abstract

Near- and mid-infrared spectroscopy methods (NIR, FTIR-ATR, FTIR-DRIFT) were evaluated for the detection and quantification of melamine in infant formula powder. Partial least-squares (PLS) models were established for correlating spectral data to melamine concentration: R2 > 0.99, RMSECV ? 0.9, and RPD ? 12. Factorization analysis of spectra was able to differentiate unadulterated infant formula powder from samples containing 1 ppm melamine with no misclassifications, a confidence level of 99.99%, and selectivity > 2. These nondestructive methods require little or no sample preparation. The NIR method has an assay time of 1 min, and a 2 min total time to detection. The FTIR methods require up to 5 min for melamine detection. Therefore, NIR and FTIR methods enable rapid detection of 1 ppm melamine in infant formula powder.