Detection of Sugars by Direct Combustion in a Flame Ionization Detector

Abstract
The detection of sugars by direct combustion in a liquid chromatography hydrogen flame ionization detector is described. A noise level of 5–8% is typical over a range of 0.01 to 2.5 weight percent aqueous sugar. The detector system uses a noble metal carrier chain to transport the sugar into the FID. Severe degradation of noble metal carriers within seventy-two hours of use is caused by deposits of caramelized and carbonized sugar on the metal as it passes into the hydrogen flame. The metal degradation is shown by scanning electron photomicrograms. Due to the metals problem this detection system is not recommended for the continuous detection of sugars. However, a braided sample carrier was developed which can be applied to analyses of species other than sugars and which will result in more uniform sample feed and less noise than chains.