Synthesis of a stationary phase based on silica modified with branched octadecyl groups by Michael addition and photoinduced thiol-yne click chemistry for the separation of basic compounds

Abstract

A novel silica-based stationary phase with branched octadecyl groups was prepared by the sequential employment of the Michael addition reaction and photoinduced thiol-yne click chemistry with 3-aminopropyl-functionalized silica microspheres as the initial material. The resulting stationary phase denoted as SiO2 -N(C18)4 was characterized by elemental analysis, FTIR spectroscopy and Raman spectroscopy, demonstrating the existence of branched octadecyl groups in silica microspheres. The separations of benzene homologous compounds, acid compounds and amine analogues were conducted, demonstrating mixed-mode separation mechanism on SiO2 -N(C18)4 . Baseline separation of basic drugs mixture was acquired with the mobile phase of acetonitrile/H2 O (5%, v/v). SiO2 -N(C18)4 was further applied to separate Corydalis yanhusuo Wang water extracts, and more baseline separation peaks were obtained for SiO2 -N(C18)4 than those on Atlantis dC18 column. It can be expected that this new silica-based stationary phase will exhibit great potential in the analysis of basic compounds.

Liquid chromatographic separation of alkaloids in herbal medicines: Current status and perspectives

“…Common combination in MMLC includes RPLC/IEC [82,83], RPLC/HILIC [84,85], or even more than two separation modes such as RPLC/IEC/HILIC [86,87]. For example, a novel reversed‐phase/ion‐exchange mixed‐mode stationary phase SiO 2 ‐N(C18) 4 (shown in Figure 2A) was successfully synthesized, with various shielding groups (tertiary amine, thioether, and ester) embedded in branched octadecyl groups [82]. This new column was then used to separate water extracts of the rhizomes of Corydalis yanhusuo W. T. Wang.…”

“…Structures of mixed‐mode stationary phase: (A) SiO 2 ‐N(C18) 4 [82], (B) SIL‐PS [87], (C) C18‐COOH [86], and (D) C18‐Diol [85]…”

Controllable preparation of a hydrophilic/ion‐exchange mixed‐mode stationary phase by surface‐initiated atom transfer radical polymerization using a mixture of two functional monomers

“…This method is currently the most common. (ii) Two types of functional organic molecules are mixed to react with the substrate . For example, octadecyltrichlorosilane and (γ‐glycidoxypropy)trimethoxysilane were simultaneously bonded onto SiO 2 to generate an RPLC/HILIC stationary phase .…”