Cereal Chem 62:6-11   |  VIEW ARTICLE
Detection and Gas-Chromatographic Determination of Propionic Acid Added as a Preservative to Corn.

W. M. Lamkin, N. D. Luginsland, and Y. Pomeranz. Copyright 1985 by the American Association of Cereal Chemists, Inc. 

A simple, rapid gas-chromatographic procedure was developed for quantitatively determining the low levels of propionic acid in treated corn. The sample to be analyzed was homogenized in water containing eta- butyric acid as an internal standard, and the resulting aqueous solution was analyzed directly by gas chromatography, thus eliminating any distillation or solvent extraction step. Homogenization required 15 min; less than 4 min was needed for chromatographic separation. Over the range of 0.2-1.0%, the method was accurate to within a few hundredths of a percent, and it was sufficiently sensitive to allow analysis on a single kernel. Propionic acid at a concentration of less than 1 ppm could be detected in the aqueous extract. A procedure employing methyl red was also devised as a screening method for detecting the acid in treated kernels.