Thermal decomposition of vitamin C: An evolved gas analysis-ion attachment mass spectrometry study.

Evolved gas analysis-ion attachment mass spectrometry (EGA-IAMS) was utilised to study the real-time non-isothermal decomposition of vitamin C. Dehydro-l-ascorbic acid, which has until this study been undetectable from the solid phase degradation of vitamin C, was observed as a decomposition product. While it is an important compound because it possesses some biological activity, dehydro-l-ascorbic acid is difficult to measure due to its chemical instability. In the present study using EGA-IAMS, we were able to detect dehydro-l-ascorbic acid from the thermal degradation of vitamin C. Our EGA-IAMS results obtained from the thermal decomposition of vitamin C were compared with a previous study employing pyrolysis-gas chromatography-mass spectrometry (Pyr-GC-MS). The observed quantitative and qualitative differences of the pyrolysis products obtained by the two techniques (EGA-IAMS vs. Pyr-GC-MS) are in part due to the difference in transportation time of the products out of the pyrolysis chamber.