THERMAL-DECOMPOSITION PRODUCTS OF ASPARTAME AS DETERMINED BY PYROLYSIS-GAS CHROMATOGRAPHY MASS-SPECTROMETRY

The thermal decomposition products of aspartame at temperatures rangin g from 350 to 950 degrees C were determined by pyrolysis-gas chromatog raphy/mass spectrometry (Py-GC/MS), using a quartz sample holder, plac ed in a platinum coil filament pyrolyzer, and an ion trap detector mas s spectrometer. Fragments typical of the amino acid constituents of as partame, along with other aspartame-diagnostic fragments, were determi ned in the pool of pyrolysis fragments. Pyrolyses were replicated for aspartame samples ranging from 0.2 to 1.3 mg and the reproducibility o f the results was determined. Samples were pyrolyzed as they were or i n the presence of tetramethylammonium hydroxide in order to achieve th ermally assisted hydrolysis methylation (THM). The results obtained fr om the Py-GC/MS and THM-GC/MS of table-top sweeteners and a soft drink containing aspartame are discussed in view of using such a technique as a rapid tool to determine aspartame content in food products.