Determination of glucosamine and monitoring of its mutarotation by hydrophilic interaction liquid chromatography with evaporative light scattering detector

Abstract

Saccharides and their derivatives are typical polar analytes without a suitable UV-chromophore that are nowadays analyzed by HPLC (high-performance liquid chromatography) under HILIC (hydrophilic interaction liquid chromatography) mode. Usually an evaporative light scattering detector (ELSD) is utilized which, however, gives a nonlinear response. A procedure to overcome the problem of mutarotating (time-varying) analytes recorded with such a nonlinear response detector is described. The procedure was applied for determination of glucosamine in two commercially available pharmaceutical formulations containing the common inorganic ions that the detector gives a response to. Under optimized conditions, both the anomers of glucosamine were separated and could be determined separately. Owing to the short retention time of the analyte (a run time <4 min) and relatively slow kinetics of the anomeric conversion (equilibration time 2.5 h), mutarotation could be monitored and corresponding rate constants calculated.

Enhancing the specificity of chitin determinations through glucosamine analysis via ultra-performance LC-MS

“…As such, it was concluded that the two peaks corresponded to two anomeric forms of glucosamine. The ratio of the peak areas was calculated as 25.8/74.2 which was in good agreement with previously published results (38,39), meaning that the obtained peaks corresponded to the β-anomer (tR = 0.87 min) and α-anomer (tR = 1.03 min) of glucosamine, respectively. The incomplete baseline separation can be attributed to the interconversion between the two anomers through mutarotation, as reported previously (15,(38)(39)(40).…”

“…The ratio of the peak areas was calculated as 25.8/74.2 which was in good agreement with previously published results (38,39), meaning that the obtained peaks corresponded to the β-anomer (tR = 0.87 min) and α-anomer (tR = 1.03 min) of glucosamine, respectively. The incomplete baseline separation can be attributed to the interconversion between the two anomers through mutarotation, as reported previously (15,(38)(39)(40). For calibration and quantification, both peaks as well as the plateau were integrated and the total area was used.…”

Rapid HPLC Method for Determination of Isomaltulose in the Presence of Glucose, Sucrose, and Maltodextrins in Dietary Supplements

“…Initial experimental conditions for the method optimization were based on recently published papers on study of monosaccharides and disaccharides retention on a polyol stationary phase [ 25 , 26 , 27 , 55 ], where a diol column (Lichrosphere100 DIOL, Merck, Darmstadt, Germany) [ 25 , 26 ] was mostly applied, but in this paper we used a HALO PentaHILIC column that showed a better performance [ 27 ]. Due to the high affinity towards the stationary phase, a flow rate of 2.0 mL/min could be maintained in all experiments.…”

“…Therefore, a compromise between high retention (high resolution) and sufficient peak area must be chosen. To find better experimental conditions we followed our own experience [ 27 , 55 ]; in the following experiments several ammonium buffers (formate, acetate, bicarbonate) in a mixture with acetonitrile were tested.…”

“…A possible approach is to find an exponent m < 1 that the peak area is powered to. Typically, the value lies in the range 0.65–0.80 [ 27 , 55 ]. The exponent can be easily found as a slope of a graph log (concentration) vs. log (peak area).…”