1 Introduction
2 Experimental
2.1 Preparation of TFPB-DHzDS and TFPB-DHzDS coated capillary with different thicknesses
2.2 Preparation of standard solutions
2.3 Real samples preparation
3 Results and discussion
3.1 Characterization of TFPB-DHzDS and TFPB-DHzDS coated capillary
3.2 Effect of electroosmotic flow (EOF) on separation
3.3 CEC separation
Fig.4 Effect of TFPB-DHzDS COFs coated capillaries with different monomer concentration for separation of PAHs. Operating conditions: 10 mmol∙L–1 borax, 32.5% acetonitrile, pH = 10.00 (0.5–4.0 mg∙mL–1); 10 mmol∙L–1 borax, 37.5% acetonitrile, pH = 10.00 (8.0 mg∙mL–1). Spectral peak designation: 1. NAP; 2. ANA; 3. ANT; 4. PHE; 5. PYR; 6. BPH. Operating voltage: +20 kV; detection wavelength: 226 nm. |
Fig.5 (a, b) Comparison of the separation of the two groups PAHs based on the TFPB-DHzDS coated capillary; (c, d) based on the bare capillary and GLYMO-coated capillary. Conditions: 10 mmol∙L–1 borax with 27.5% acetonitrile, pH = 10.00 for (a) and (c); 10 mmol∙L–1 borax with 45.0% acetonitrile, pH = 10.50 for (b) and (d). Running voltage was +20 kV. |
3.4 Separation performance of the TFPB-DHzDS coated capillary
Tab.1 Linear range, linear equation, correlation coefficient, LOD and LOQ of PAHs |
Analyte | Linearity/(μg∙mL–1) | Linear equationa) | R2 | LODb)/(μg∙mL–1) | LOQc)/(μg∙mL–1) |
---|---|---|---|---|---|
NAP | 0.20–100.00 | Y = 6065.46X + 99.25 | 0.9924 | 0.06 | 0.19 |
ANA | 0.20–100.00 | Y = 7905.02X – 569.37 | 0.9997 | 0.04 | 0.15 |
ANT | 1.00–100.00 | Y = 1458.97X – 1978.34 | 0.9899 | 0.24 | 0.79 |
PHE | 1.00–100.00 | Y = 1059.92X – 551.51 | 0.9866 | 0.33 | 1.09 |
PYR | 1.00–100.00 | Y = 1812.32X – 252.53 | 0.9981 | 0.19 | 0.64 |
BPH | 2.50–100.00 | Y = 886.41X – 820.70 | 0.9835 | 0.39 | 1.31 |
FLU | 0.50–100.00 | Y = 1897.61X – 928.69 | 0.9952 | 0.16 | 0.52 |
FLT | 0.25–100.00 | Y = 4742.37X – 317.77 | 0.9824 | 0.06 | 0.21 |
BaA | 0.25–100.00 | Y = 6340.83X – 965.01 | 0.9999 | 0.05 | 0.16 |
BbF | 0.25–100.00 | Y = 6818.69X + 2713.46 | 0.9937 | 0.04 | 0.14 |
a) Y: peak area; X: concentration of analyte; b) calculated on the basis of 3s/k (s was the deviation of baseline; k was the slope of the linear equation); c) calculated on the basis of 10s/k. |
3.5 Repeatability and stability of the TFPB-DHzDS coated capillary
Fig.6 Electrophoretic spectra of two groups of PAHs based on TFPB-DHzDS coated capillary for 200 runs. Conditions: (a) 10 mmol∙L–1 borax with 32.5% acetonitrile, pH = 10.00; (b) 10 mmol∙L–1 borax with 45.0% acetonitrile, pH = 10.50. Running voltage: +20 kV; detection wavelength: 226 nm. |
3.6 Real samples analysis
3.7 Possible separation mechanism
Fig.7 Molecular simulations of the interactions of ten PAHs with COF TFPB-DHzDS coated capillary column: (a) 1 NAP, 2 ANA, 3 PHE, 4 ANT, 5 PYR, 6 BPH; (b) 7 FLU, 8 FLT, 9 BaA, 10 BbF. Carbon atoms of COF TFPB-DHzDS were in cyan, nitrogen atoms in blue, oxygen atoms in red and hydrogen atoms in white; all PAHs molecules are shown in red; the binding energies between PAHs and COF TFPB-DHzDS are shown in blue. |