Anhydrous Hydrogen Fluoride and Cell-Wall Analysis

Abstract

A venerable tradition for hydrogen fluoride use in wood analysis dates back to Gore (1869) who determined the formula as HF and also observed that in anhydrous HF: “Paper, cotton-wool, calico, gelatin, and parchment were instantly converted into glutinous substances and dissolved.” Later workers (e.g., Clark 1962) used strong aqueous HF to macerate woody tissues and estimate lignin content, while the recent revival of Fredenhagen and Cadenbach’s (1933) early work using anhydrous HF to “crack” cellulose, is a promising chemical alternative to microbial degradation of cellulosics for fuels and chemicals (Smith et al. 1983); ultimately biomass will be too valuable to burn! However, only much more recently have we appreciated anhydrous HF as a very highly selective solvolysis reagent, triggered by its use in peptide chemistry as a “deprotecting” reagent. By analogy this led to the use of anhydrous HF as an effective and facile method for the chemical deglycosylation of glycoproteins and mucoproteins (Mort and Lamport 1977). Indeed the selectivity for solvolysis of different glycosidic bonds is quite remarkable at subzero temperatures, so that, as described here, it becomes possible to dissect difficult and complex saccharide structures with an almost surgical precision.