A covalent organic framework for chiral capillary electrochromatography using a cyclodextrin mobile phase additive

Abstract

Covalent organic frameworks (COFs) have been recognized as promising solid phases in capillary electrochromatography (CEC). Imine-based COF-coated open-tubular CEC column (COF TpBD-coated OT column) was prepared and characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectra, thermogravimetric analysis (TGA), nitrogen adsorption/desorption (Brunauer-Emmett-Teller [BET]), and scanning electron microscopy (SEM). The results showed that the column efficiency was up to 26,776 plate/m, and the thickness of stationary phase was about 6.00 μm for the column prepared under the optimal conditions. Enantioseparation of 15 kinds of the single chiral compounds (histidine, arginine, lysine, leucine, threonine, methionine, valine, aspartic acid and glutamic acid, fipronil, diclofop, imazamox, quizalofop-p, imazethapyr, and acephate) and 3 kinds of mixed amino acids racemaces (valine, methionine, and glutamic acid) were performed with three methods: capillary electrochromatography with COF TpBD-coated OT column (Method 1), CEC with COF TpBD-coated OT column as the separation channels, and capillary electrophoresis (CE) with HP-β-CD as the chiral mobile phase additive (Method 2) and CE with HP-β-CD as the chiral mobile phase additive (Method 3). Separation efficiency and chiral selectivity of Method 2 was best among the three methods. Under the optimal separation conditions of Method 2, all the enantiomers reached the baseline separation regardless of the single chiral compounds or the mixed amino acids. Relative standard deviation (RSDs) of the mean column efficiency for reproducibility and stability was in the range of 0.46-1.49%. This combination of CEC and CE has great potential for use in chiral separation.

Recent applications and chiral separation development based on stationary phases in open tubular capillary electrochromatography (2019–2022)

“…[ 26 ] used isocyanate-β-CD as a chiral selector, to decorate a Ttpa-1 COF OT column synthesized from 1, 3, 5-triformylphloroglucinol (Tp) and 1, 4-phenylenediamine (Pa-1), which was used to separate tetracyclines, sulfonamides, cephalosporins, and AAs. The COF TpBD-coated OT column [ 27 ] could perform baseline separation of fifteen monochiral compounds and three mixed AAs. It also appeared as a boron-related multilayer COF-5 material.…”

“…Overall, we provide readers interested in OT-CEC with the most up-to-date overview of this field, and the related new SPs from 2019 to 2022 are listed in Table 1 [ 3 , [5] , [6] , [7] , [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] , [64] , [65] ]. PubMed and Web of Science were used to search the following characters (also their acronyms) alone or in combination: “Open tubular”, “Capillary electrochromatography”, “Chiral separation”, “Stationary phase”, and “Coating” for relevant literature to analyze recent OT-CEC developments.…”

Applications of electrophoresis for small enantiomeric drugs in real‐world samples: Recent trends and future perspectives

“…Still at the beginning, instead, is the research on the use of MOFs and COFs, which are porous materials capable of forming complex supramolecular structures with a large surface area, which seem suitable to be applied in chiral CE. Most studies concern the development of chiral stationary phases with these materials used for coating the capillary [85][86][87][88][89]. It is essential to mention that costly CSs are always lost in CE.…”

Chirality in Organic and Mineral Systems: A Review of Reactivity and Alteration Processes Relevant to Prebiotic Chemistry and Life Detection Missions

“…In addition to existing instruments, the development of new instruments or instrument capabilities to detect chirality in spaceflight is a necessary component in the search for signs of past life. Advancements in the fields of organic separation (e.g., [500][501][502][503][504]) and detection through mass spectrometry [505,506] are needed to enhance the field of chiral separation on spaceflight missions. Refinement of traditional chiral separation and detection methods as well as the development of new analytical strategies to investigate chiral organics [407,420,[507][508][509] and minerals [510] should be prioritized.…”