Fig. 1 Three common click reactions that mainly emerged in analytical chemistry a. azide-alkyne reaction; b. thiol-alkyne reaction; c. thiol-alkyne reaction.

Fig. 2 Synthetic pathway of the bilayer cyclodextrin-based chiral stationary phase (CD-CSP)[15] a. synthesis of alkyne-β-CD; b. synthesis and immobilization of N3-β-CD; c. click reaction-mediated construction of the bilayer CD-CSP.

Fig. 3 Chiral chromatographic separation materials prepared based on thiol-alkene addition reaction a. mono(6-mercapto-6-deoxy)-β-CD-CSP[24]; b. QN-CD-CSPs[31]; c. 3,5-dichlorophenyl carbamated cellulose-bonded CD-CSP[32]; d. L-Cys-PCN-222[37].

Fig. 4 Non-chiral chromatographic separation materials prepared based on thiol-alkene reaction a. C18-functionalized organosilicon monolith[42]; b. Sil-VMB-VSS[48]; c. quaternary ammoniation functionalized cysteine-zwitterionic stationary phase[55]; d. Sil@Poly (AHPS-co-MBAAm)[56].

Fig. 5 Illustration for the thiol-alkyne click strategy to post-synthesize chiral microporous organic networks (MONs) for chiral GC[67]

Fig. 6 Schematic diagram of the sliding supramolecular polymer brushes formation strategy via the azide-alkyne click coupling reaction[71]

Fig. 7 Membrane separation materials prepared based on thiol-alkene click reaction a. PEG-modified PAN membrane[77]; b. PEG-g-PES comb-like copolymer membrane[82]; c. tetrabromobisphenol A molecularly imprinted membrane[85].

Fig. 8 (a) Schematic illustration for the fabrication of polyamide/covalent organic framework-Cys (PA/COF-C) nanocomposite membrane by an interfacial bridging method, and (b) chemical reaction of the formation of PA/COF-C layer[93]