Enantioseparation characteristics of the chiral stationary phases based on natural and regenerated chitins

Abstract

Natural and regenerated chitins were derivatized with 3,5-dimethyphenyl isocyanate. The corresponding chiral stationary phases were prepared by coating the resulting chitin derivatives on 3-aminopropyl silica gel. The swelling capacity of the chitin derivatives, enantioseparation capability, as well as eluents tolerance of the chiral stationary phases were evaluated. The results demonstrated no remarkable difference in enantioseparation capability between natural and regenerated chitins based chiral stationary phases. The similar enantioseparation characteristics of two chiral stationary phases could be understood by comparing the IR spectra of related chitin derivatives. The one of the two chiral stationary phases prepared by coating the chitin derivative with a lower molecular weight generally provided better enantioseparations. All chiral stationary phases can work in 100% chloroform, 100% ethyl acetate, 100% acetone, and the mobile phases containing a certain amount of tetrahydrofuran. The chiral stationary phase prepared from the chitin derivative with the highest swelling capacity exhibited better enantioseparations than others. This chiral stationary phase was damaged by flushing with 100% tetrahydrofuran, however, the enantioseparation capability was recovered again after the column was allowed to stand for 1 month. Furthermore, the recovered chiral stationary phase provided better enantioseparations for some chiral analytes than before.

Chiral Stationary Phases for Liquid Chromatography: Recent Developments

“…Chitin and chitosan-based CSPs have received particular attention in the last few years [51]. Through continuous efforts to develop effective CSPs, other recent reports describing the use of chitin [101,102] and chitosan [95,96,97] derivatives are rising, with the carbamates as one of the most studied [49]. The growing interest in these polysaccharides comes from the fact that they have low solubility, which allows the use of a wide variety of mobile phases [52].…”

“…Mei et al [101] derivatized natural and regenerated chitins with 3,5-dimethyphenyl isocyanate, to prepare CSP52 and CSP53–55, respectively (Figure 2), with the difference between them only related to the raw material. The regenerated chitins were obtained from natural chitins, after a treatment with acetic anhydride, showing a more promising performance.…”

“…The regenerated chitins were obtained from natural chitins, after a treatment with acetic anhydride, showing a more promising performance. They pointed out that CSP prepared from selectors with lower molecular weight provided an improved resolution [101]. The best chromatographic results were obtained for voricomazole, with Rs = 11.7 and α = 3.06.…”

Preparation and evaluation of a deoxycholic‐calix[4]arene hybrid‐type receptor as a chiral stationary phase for HPLC

“…Among various available analytical techniques for this purpose, HPLC seems to be the most popular and the most efficient technique to analyze racemic mixtures and to obtain enantiopure compounds . New HPLC chiral stationary phases (CSPs) with high chiral recognition for the separation of chiral molecules with varying structural properties are being introduced every day . These stationary phases may find application in different fields, such as organic synthesis, natural products research, pharmaceuticals, food science, and environmental studies.…”

“…New HPLC chiral stationary phases (CSPs) with high chiral recognition for the separation of chiral molecules with varying structural properties are being introduced every Abbreviations: AIBN, Azobisisobutyronitrile; CSP, chiral stationary phase; DCM, dichloromethane; DEA, diethylamine; DNB-DL-leucine, N-(3,5-dinitrobenzoyl)-DL-leucine; DNB-DL-valine, N-(3,5-dinitrobenzoyl)-DL-valine; DNB, N- (3,5-dinitrobenzoyl); EtOH, ethanol; HOAc, acetic acid; IPA, 2-propanol; MeOH, methanol; TFA, trifluoroacetic acid; THF, tetrahydrofuran Conflict of interest: The authors have declared no conflict of interest. day [6]. These stationary phases may find application in different fields, such as organic synthesis, natural products research, pharmaceuticals, food science, and environmental studies.…”