Electronic Supplementary Material
Preconcentration of the antibiotic enrofloxacin using a hollow molecularly imprinted
polymer, and its quantitation by HPLC
Yiwei Tang1, 2, 3 · Min Li1, 2 · Xue Gao2,3 · Xiuying Liu1, 3* · Yong Ma2, 3 · Yi Li1 ·
Yongxia Xu1 · Jianrong Li1, 2, 3*
1 College of Food Science and Project Engineering, Bohai University, Jinzhou 121013, China
2 Food Safety Key Lab of Liaoning Province, Bohai University, Jinzhou 121013, China
3 National & Local Joint Engineering Research Center of Storage, Processing and Safety
Control Technology for Fresh Agricultural and Aquatic Products, Bohai University, Jinzhou
121013, China
*Corresponding
author:
E-mail:
tianlanyijiu81@163.com
(Jianrong
liu0514111@163.com (Xiuying Liu), Tel: +86 416 3400008, Fax: +86 416 3400013
Fig.S1 FT-IR spectra of KH570-K2Ti4O9 and K2Ti4O9.
Li),
Fig.S2 FT-IR spectra of ENR, MIPs with ENR and MIPs without ENR.
Fig. S3 XRD spectra of K2Ti4O9, MIPs and h-MIPs.
Fig. S4 The adsorption capacity of h-MIPs and h-NIPs in different adsorption solution.
Fig. S5 Structures of enrofloxacin, pefloxacin, norfloxacin, enoxacin, lomefloxacin,
levofloxacin, gatifloxacin, ciprofloxacin, fleroxacin and sparfloxacin.
Fig.S 6 Recoveries of the h-MIPs-SPE columns at different flow rate (A) and pH (B).
Optimization of h-MIPs-SPE procedures
The effect of loading flow rate was studied by loading 50 mL of 25 ng mL-1 ENR
methanol solutions on the h-MIPs-SPE columns at different flow rates (0.5-2.0 mL min-1) (Fig.
S6A). When the flow rate was in the range of 0.5-1.0 mL min-1, the recovery of ENR
decreased from 86 to 72% with the increase of the flow rate. In consideration of the binding
efficiency, the flow rate of 0.5 mL min-1 was chosen in the following studies.
The pH of the loading solution was also studied in our experiment by percolating ENR
methanol solution (pH adjusted 3 to 8 with sodium hydroxide or acetic acid) through the
h-MIPs-SPE columns at a flow rate of 0.5 mL min-1. The experimental results (Fig. S6B)
revealed that the pH of the loading solution had a significant impact on the interaction
between the monomer and the template, especially in the acidic environment (pH 3-6). In the
neutral or alkaline loading solution environment, the recovery was more than 92%. This may
be because free hydrogen protons in a high acidity condition will compete with ENR and
disrupt the hydrogen-bonding interaction between imprinted site and the analytes. A similar
phenomenon was also observed by [1]. Therefore, the pH 7 of loading solution was selected
in this work.
In order to obtain the best recovery, mixed solutions of different ratio of methanol and
acetic acid as eluent were estimated. The results indicated that the satisfactory recovery of
ENR (98%) was obtained using the mixture of methanol-acetic acid (8:2, v/v) as elution
solution. In addition, elution volume was also optimized. In brief, various volumes from 5 to
35 mL of the mixture of methanol/acetic acid (8:2, v/v) were evaluated. The results showed
that the recovery of the template molecular did not increase as more than 25 mL of eluent was
applied. Consequently, 25 mL of the eluent were applied in the h-MIPs-SPE procedure.
Table S1 Figures of merit of recently reported nanomaterial-based methods for preconcentration and
determination of enrofloxacin
Material
MIPs
MIPs
Methods
HPLC with
diode array
detector
Flow
injection
method with
fluorescence
detector
Linear rang
(μg L-1 or μg
kg-1)
LODs
(μg L-1 or
μg kg-1)
Recovery
(%)
RSD
(%)
30.0-2.0×105
8.0
82.7-96.6
1.0-80.0
0.27
Advantanges/
Limitations
Ref.
4.0-6.4
High affinity/High LOD
[2]
84.0-119.0 2.3-8.8
Low LOD/Complicated
operating parameters
[3]
MIPs
Mass
spectrometry
4.4-200.0
1.3
91.9-92.9
h- MIPs
HPLC with
fluorescence
detector
0.5-16.0
0.24
68.9-110.3 1.6-4.4
<11
Wide linear rang, good
recovery/
Relatively poor
reproducibility
Fast binding rate, large
adsorption amount, and
good specificity/ Relatively
poor recovery
[4]
Own
work
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polymers prepared by the hybrid imprinting method. Polymer 48: 5565-5571.
[2] Qiao FX, Sun HW (2010) Simultaneous extraction of enrofloxacin and ciprofloxacin
from chicken tissue by molecularly imprinted matrix solid-phase dispersion. J
Pharmaceut Biomed 53: 795-798.
[3] Luaces MD, Urraca JL, Pérez-Conde MC, Martínez Alfonso NC, Valdés-González AC,
Gutiérrez AM, Moreno-Bondi MC (2013) Chemiluminescence analysis of enrofloxacin
in surface water using the tris(1,10-phenantroline)-ruthenium(II)/peroxydisulphate system
and extraction with molecularly imprinted polymers. Microchem J 110: 458-464.
[4] Moreno-González D, Lara FJ, Gámiz-Gracia L, García-Campaña AM (2014) Molecularly
imprinted polymer as in-line concentrator in capillary electrophoresis coupled with mass
spectrometry for the determination of quinolones in bovine milk samples. J Chromatogr
A 1360: 1-8.