Separation of benzodiazepines on a new carbohydrate-based chiral stationary phase for HPLC

Characterization of β‐cyclodextrin modified SiO2

“…The grafting yields obtained by XPS are 20–80% higher than those obtained by TGA or elemental analysis. Though unexpected, the results are easily explained based on previous studies of the system9 where it is speculated that the grafting happens primary on the outer surface and the largest pores based on BET results 39. The XPS data compared to the TGA and elemental analysis data suggests that the distribution of the β‐CD throughout the material is heterogeneous.…”

“…of carbon, hydrogen and nitrogen in the samples. It should be noted that Ponchel et al explains that elemental analysis is not applicable since the samples does not contain heteroelements where Feng et al and Stalcup et al use elemental analysis as the only quantitative method to investigate the yield of similar products 6, 9, 28. The discrepancy in literature is investigated by comparing elemental analysis to TGA and XPS data.…”

“…The use of different materials as chiral selectors in chromatography has been widely investigated with systems such as amylose, cellulose and cyclodextrins (CDs). All three materials are derived from starch and have the ability to separate chiral molecules based on their different interaction with the different enantiomeric forms1, 2 if the molecule is bound to the column material 3–9. One such column material is silica gel which is widely used in column chromatography due to its high mechanical stability, large surface area and chemical inertness 10–12.…”

“…Many of the analytical methods, such as elemental analysis,9 thermogravometric analysis,28 titration with terazolium blue,30 etc. give the same end result such as qualitatively determining β‐CD in the material.…”