Development of an advanced derivatization protocol for the unambiguous identification of monosaccharides in complex...

The separation and analysis of complex monosaccharide mixtures is highly challenging and requires typically carefully selected derivatization procedures to avoid changes in the sample composition. Here we present in a comparative study several single- and two-step derivatization approaches for LC and GC separations using a set of reference compounds ranging from C1 building block such as formaldehyde to C6 monosaccharides. Separation conditions have been optimized resulting in the simultaneous separation of 15 unbranched aldoses. By parallel derivatization using hydroxylamine hydrochloride (HACl)/ N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and O-ethylhydroxylamine hydrochloride (EtOx)/ N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and comparative GC measurements we developed a protocol for the unambiguous identification and separation of aldoses, ketoses, alditols and aldonic acids, which commonly occur in complex sugar mixtures as reaction by-products or decomposition products. In particular this procedure helps to deconvolute overlapping analytes and facilitates quantification. Additionally, the method presented here has been investigated in regard to storage life, detection limits, quantification and MS analysis. The broad applicability of this method to different sample matrices is shown for the analysis of food samples and complex aldol reaction mixtures in the formose reaction, which is of great relevance in the context of the origin of life.