Advantages of Evaporative Light Scattering Detection for the Purity Control of Commercial Cyclodextrins

Abstract

Using an Evaporative Light Scattering Detector (ELSD) which is a universal detection system compatible with gradient elution, allowed satisfactory analysis of the non volatile impurities in cyclodextrins. ELSD performances for cyclodextrin analysis were evaluated. The detection capabilities of ELSD are better than those of RI and Polarimetric detectors (detection thresholds obtained with the ELSD are about 80 ng). Analyses were performed on different Phenyl columns with acetonitrilewater mobile phases in isocratic or gradient mode. Potential impurities of β-CD and of TM-β-CD, which included 7 linear (glucose to maltoheptaose), 2 unbranched cyclic (α- and γ-CD) glucose polymers and partially methylated cyclodextrins, have been determined. As the ELSD response factors of these homologous compounds are highly similar, it is possible to evaluate impurity levels without previous identification. The methods presented provide good selectivity and sensitivity and can also be used to compare different sources of cyclodextrins.