The FDAM method: Determination of carboxyl profiles in cellulosic materials by combining group-selective fluorescence labeling with GPC

A novel method for accurate determination of the carboxyl content in cellulosic materials by fluorescence labeling with 9H-fluoren-2-yl-diazomethane (FDAM) has been developed. The procedure can readily be implemented into a GPC system with RI and MALLS detectors, requiring additional fluorescence detection. The labeling conditions were optimized by means of sugar acid model compounds and were transferred to the cellulose case. Kinetics of the labeling and the influence of reaction parameters were comprehensively studied. For the first time, carboxyl profiles of cellulosics, i.e., the carboxyl content relative to the molecular weight distribution, were obtained.