Caption for ESM figures

Fig.S1a. Synthesis of VBM+Cl-IL

Fig.S1bMS spectrum of VBM+Cl-IL

ESI ionic source was used with positive mode in the MS experiment. The m/z 151.0 and 337.0 could be found in Fig. S1, which were in accordance with the mass of VBM+ and 2(VBM+)Cl(the isotope peak indicated the present of Cl), respectively.

Fig.S2. Investigation of the pretreatment ability on the monolithic column.

Conditions: Monolithic column: 50 × 4.6 mmI.D; flow rate: 1.0 mL min-1; temperature: room temperature; mobile phase: a: water; b: 0-15min 60% methanol, 15-20min 60-80% methanol, 20-30min 80% methanol; detector wavelength: 280nm; amount of injection: 5.0 μL of blank human plasma.

(a): (1): empty column with the peak area as 2491172 mAu min-1

(2): monolithic columnwith the peak area as 2424137mAu min-1

(b): there wasno interfering near the retention time of three antihypertensives

Fig.S3. Investigation of the enrichment ability on the monolithic column.

Conditions: monolithic column: 50 × 4.6 mmI.D; flow rate: 1.0 mL min-1; temperature: room temperature; detector wavelength: 237 nm; analytes: nifedipine, nitrendipine and felodipine (0.1 mg mL-1 of solutions); amount of injection: 3.0 μL.

There was no peak when water as the mobile phase(a). nifedipine(b), nitrendipine(c) and felodipine(d) were eluted by methanol, respectively.

Table.S1TheRSD values of run-to-run for retention times and peak areas of column A

Table.S2TheRSD values of batch-to-batch for retention times and peak areas of four different columns

Fig.S1a

Fig.S1b

Fig.S2a

Fig.S2b

Fig.S3

Table.S1

Samples / Concentration / Sampling numbers / Retention times / RSD% / Peak areas / RSD%
Nifedipine / 100 ng mL-1 / 1 / 7.754 / 0.91 / 4979 / 2.08
2 / 7.568 / 4826
3 / 7.598 / 4744
4 / 7.662 / 4896
5 / 7.708 / 4746
Nitrendipine / 100 ng mL-1 / 1 / 14.881 / 0.88 / 3498 / 2.95
2 / 14.574 / 3265
3 / 14.521 / 3512
4 / 14.605 / 3334
5 / 14.669 / 3378
Felodipine / 100 ng mL-1 / 1 / 23.978 / 0.62 / 3511 / 2.50
2 / 23.911 / 3445
3 / 23.858 / 3599
4 / 23.923 / 3401
5 / 23.574 / 3389

Table.S2

Analytes / Columns / Concentration / Retention
times / RSD% / Peak
areas / RSD%
Nifedipine / A / 100 ng mL-1 / 7.568 / 3.18 / 4826 / 4.69
B / 7.927 / 4537
C / 7.879 / 4904
D / 7.416 / 5082
Nitrendipine / A / 100 ng mL-1 / 14.574 / 2.67 / 3265 / 3.23
B / 14.902 / 3314
C / 14.843 / 3089
D / 14.041 / 3147
Felodipine / A / 100 ng mL-1 / 23.911 / 4.51 / 3445 / 3.19
B / 25.423 / 3287
C / 25.016 / 3510
D / 23.009 / 3305