Direct and simultaneous determination of representative byproducts in a lignocellulosic hydrolysate of corn stover via gas chromatography–mass spectrometry with a Deans switch

Pretreatment is one of the most important steps in producing fuel ethanol from lignocellulosic biomass. Simple, fast and accurate quantification of byproducts in lignocellulosic hydrolysates is critical to optimize the pretreatment procedures, but still a challenge. In this paper, a new GC–MS (SIM) method based on a Deans switch has been developed for the determination of byproducts in a corn stover hydrolysate. The Deans switch was incorporated into a hardware system that facilitated the direct aqueous injection (DAI) on GC–MS system. Simultaneous chromatographic separation and quantification of 18 byproducts including four aliphatic acids, five furan derivatives, four phenolic compounds and five others were achieved within 45   min. The detection limits of the presented method for various byproducts were in the range of 0.007–0.832   mg/L. The within-day and between-day precisions of the method were less than 6.0% (RSD, n   =   6). The accuracy of the method was confirmed with recoveries of 86–128%. A lignocellulosic hydrolysate sample of corn stover was successfully analyzed using this method, with aliphatic acids and furan derivatives accounting for 89.15% of the selected total byproducts.