Improved cleanup and derivatization for gas chromatographic determination of monosodium glutamate in foods

A gas chromatographic procedure is described for determining monosodium glutamate (MSG) in several types of food. A sample is extracted with acetone-water (1 + 1). Acetone is evaporated and an aliquot of the extract is buffered with 1M NH4OH-1M NH4Cl pH 9 solution, and chromatographed directly on a column of QAE Sephadex A-25 that has been pretreated with the same buffer. MSG is eluted with 0.1N HCl, and a portion of the eluate is evaporated to dryness and reacted with dimethylformamide(DMF)-dimethylacetal to form the glutamic acid derivative, which is injected into a gas chromatograph and measured by flame ionization detection. Recoveries of MSG from sample fortified at 5-500 mg ranged from 92.8 to 100%.