6-15: Methods for determining sugars and hydroxymethyl furfural in biomass

Common biomass sugars and hydroxymethyl furfural (HMF) are routinely analyzed during biofuel processing. It is important to monitor sugars to optimize processes for maximizing the yield of ethanol. There is also a growing interest in monitoring HMF levels, as it is a ‘platform compound’ that can be used to synthesize several compounds (solvents, fuels etc.) that are currently derived from crude oil.

This presentation describes high-performance anion-exchange chromatography with pulsed amperometric detection methods for the determination of (i) sugars (ii) HMF in acid-hydrolyzed corn stover using electrolytically generated hydroxide eluent, separation on strong anion-exchange columns, and electrochemical detection with disposable gold working electrodes.

Biomass samples often have sugar concentration over 100 g/L, and the common sugars are fucose, sucrose, arabinose, galactose, glucose, xylose, mannose and fructose. The method for sugar analysis has a short run time (8 min), while resolving all the sugars,  linear range of 0.5-2 g/L, retention time precisions <0.01-0.12%, peak area precisions 1.7-2.7%, and acceptable recoveries (70-112%). The described method is capable of handling the high concentration biomass samples with minimal sample preparation (i.e. the strong acid hydrolysate just needs to be diluted and the column is not affected by the amount of sulfate in the diluted sample).

The proposed method for HMF has a broad linear range (0.1-1000 mg/mL), low detection limit (0.04 mg/mL), high precision, and good recovery (112%). These methods require no eluent preparation and due to short analysis time, good sensitivity, and consistent response, can be used for routine sugar and HMF analysis.