Evaluation of the Oxidation of Rice Husks with Sodium Hypochlorite Using Gas Chromatography-Mass Spectrometry and Direct Analysis in Real Time-Mass Spectrometry

Abstract

Rice husk powder was oxidized in aqueous sodium hypochlorite solution under mild conditions with different reaction times. Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry (GC-MS), and direct analysis in real time-mass spectrometry (DART-MS) were used to analyze the oxidation products. Results showed that oxidation was a feasible way to depolymerize the macromolecules in the biomass and convert hydroxyl groups to carboxyl groups. In total, 113 organic compounds in oxidation products with molecular mass less than 500 Da were identified using GC-MS. As an ambient ionization technique, DART-MS was applied to the determination of biomass derivatives and revealed mass distribution and molecular structure information for the rice husk oxidation products.