Tianpei Cai,1,2 Haijuan Zhang,1 A.F.M. Mustafizur Rahman,3 Yan-Ping Shi1 and Hongdeng Qiu1,*

Supporting information for

Silica grafted with silanized carbon dots as a nano-on-micro packing material with enhanced hydrophilic selectivity

Tianpei Cai,1,2 Haijuan Zhang,1 A.F.M. Mustafizur Rahman,3 Yan-Ping Shi1 and

Hongdeng Qiu1,*

1 CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key

Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical

Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000, China. E-mail: [email protected] (H. Qiu); Fax: +86 931 8277088; Tel: +86 931 4968877.

2 University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing

100049, China

3 Department of Applied Chemistry and Chemical Engineering, University of Dhaka,

Dhaka-1000, Bangladesh

Corresponding author: Professor Hongdeng Qiu,

Lanzhou Institute of Chemical Physics, Chinese

Academy of Science, Lanzhou 730000, China

Fax: +86 931 8277088

E-mail: [email protected]

Characterization of Sil-CDs

1 Fig. S1 High resolution TEM image of CDs

Fig. S2 Fluorescent performance of silanized CDs (a), Sil-CDs (b) and bare silica (c). (λex = 360 nm)

2 Fig. S3 FTIR spectra of Sil-CDs (red line) and Sil-AEAPMS (black line).

Separation of flavones and amino acids

Fig. S4 (a) Separation of seven flavones with Sil-CDs: wogonin (1), isorhamnetin (2), kaempferol (3), apigenin (4), quercetin (5), luteolin (6), myricetin (7),; mobile phase: 97% acetonitrile: 3% 0.1% orthophosphoric acid solution, flow rate = 1.0 mL min-1, T = 30 °C, UV detection: 254 nm. (b) Separation of seven amino acids with Sil-CDs: leucine (1), isoleucine (2), valine (3), proline (4), alanine (5), glycine (6), serine (7); mobile phase：80% acetonitrile: 20% 12 mM ammonium acetate, pH = 6.62, flow rate = 1.0 mL min-1, T = 20 °C, ELS detector: gas pressure 0.50 MPa, tube

3 temperature 45 °C, gain 16.

Fig. S5 Effect of buffer concentration on the retention factor (k) of nucleosides and bases (a), sulfonamides (b) with Sil-CDs column. Mobile phase: (a) 93% acetonitrile: 7% ammonium acetate, pH = 6.62; (b) 85% acetonitrile: 15% ammonium acetate, pH = 6.62; flow rate = 1.0 mL min-1, T = 35 °C, UV detection: 254 nm. Effect of buffer pH on the retention factor (k) of nucleosides and bases (c), sulfonamides (d) with Sil- CDs column. Mobile phase: (c) 93% acetonitrile: 7% 20 mM ammonium acetate; (d) 85% acetonitrile: 15% 10 mM ammonium acetate; flow rate = 1.0 mL min-1, T = 35 °C, UV detection: 254 nm.

Table S1 Chemical compositions (At. %) of stationary phases determined by XPS. Stationary phase C N O Si Sil-AEAPMS 46.13 2.77 30.52 20.58 Sil-CDs 44.22 4.04 31.18 20.56

Table S2 Selectivity factors of nucleosides and bases on Sil-CDs and Sil-AEAPMS.

Sil-CDs Sil-AEAPMS Retentio Selectivit Retentio Selectivit Elution order n factor y factor Elution order n factor y factor (k) (α) (k) (α)

4 uridine 3.05 adenosine 3.24 1.10 1.09 adenosine 3.35 adenine 3.54 1.20 1.02 adenine 4.02 uridine 3.62

Table S3 Selectivity factors of sulfonamides on Sil-CDs and Sil-AEAPMS.

Sil-CDs Sil-AEAPMS Retentio Selectivit Retentio Selectivit Elution order n factor y factor Elution order n factor y factor (k) (α) (k) (α) sulfadoxine 4.24 sulfadoxine 3.07 1.15 1.11 sulfadiazine 4.88 sulfadimethoxine 3.41 1.13 1.04 sulfadimethoxine 5.52 sulfadiazine 3.55 1.15 1.10 sulfathiazole 6.34 sulfathiazole 3.89

Table S4 An overview on recently reported nanomaterial-based stationary phases for separation in hydrophilic interaction chromatography. Nanomaterial Support Preparation method Characterization Applications Water contact angle test, Separation of nucleoside, Fullerene (C60+C70) Spherical Electrostatic adsorption Raman spectroscopy and nucleobases,water soluble vitamins, silica EA amino acids and sugars Covalent bonding via epoxy Graphene Spherical ring-opening and covalent SEM, EA and IR Separation of vitamin B, amino acids silica immobilization of ILs and aromatic acids Fabricate metal −organic Metal−organic Spherical frameworks on carboxylate- IR, XRD, TGA and Separation of amides, vitamins, frameworks silica terminated silica SEM nucleic acid bases, and nucleosides. microspheres Spherical Covalent bonding via Separation of sulfonamides and Nanodiamond silica amidation SEM, TEM, EA and IR sugars graphene oxide/ gold Spherical Covalent bonding via Separation of amino acids, nanoparticles silica amidation and adsorption SEM, EA and XPS nucleosides and nucleobases porous graphitic Covalent modified by aryl Separation of phenols, nucleosides carbon / diazonium chemistry XPS and ephedrines Separation of aromatic acids, phenols, porous graphitic / Covalent modified by SEM, EA and XPS sugars, amino acids and inorganic carbon thermal crosslink anion

5 EA, TEM, IR, NMR, Spherical Covalent bonding via XPS and nucleosides, sulfa compounds and Carbon nanoparticles silica amidation photoluminescence safflower injection spectra TEM, EA, TGA, IR, Spherical Covalent bonding via epoxy BET analysis, zeta nucleosides, nucleobases and Carbon dots silica ring-opening potential analysis, Cordyceps sample fluorescence imaging TEM, EA, XPS, IR, Carbon dots Spherical Covalent bonding via BET analysis, sulfonamides, nucleosides and bases, silica silanization fluorescence imaging flavones and amino acids EA, Elemental analysis; IR, Infrared spectroscopy; SEM, Scanning electronic microscopy; TGA, Thermogravimetric analysis; XPS, X-ray photoelectron spectroscopy; NMR, nuclear magnetic resonance.

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