Electronic Supplementary Material
Voltammetric determination of levofloxacin using a glassy carbon electrode modified
with poly (o-aminophenol) and graphene quantum dots
Jing-Yi Huanga, Ting Baoa, Tian-Xing Hua, Wei Wena,b,*, Xiu-Hua Zhanga, Sheng-Fu Wanga
aHubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry
of Education Key Laboratory for the Synthesis and Application of Organic Functional
Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan
430062, PR ChinabState Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha
410082, PR China
* Corresponding author. Tel.: 86 27 50865309; Fax: 86 27 88663043, E-mail address:
Scheme S1. The chemical structure of LV.
Figure S1. TEM images of GQDs (A). Size distributions of GQDs (B). SEM images of
PoAP/GQD composite film (C) and (D).
Figure S2. Influence of pH on the anodic peak current (A) and peak potential (B) of PoAP/GQD/GCE in NaAC-HAc solution containing 100 μM LV. Influence of accumulation time (C) and potential (D) on the anodic peak current of PoAP/GQD/GCE in NaAc-HAc (pH = 4.5) containing 100 μM LV.
In order to optimize the experiment conditions, the influence of pH value of 0.1 M
NaAc-HAc to the peak current and potential was studied in the work. With the increase of pH
value, the peak current reached the highest at pH 4.5 (Fig. S2A). However, when pH values
exceed 4.5, with the further increase of pH, the oxidation peak current decreased. The
dependences of peak potential (E) on pH for NaAc-HAc were shown in Fig. S2B, when the
pH values increasing, the anodic peak potential shifted to lower values. It can be verified that
the chemical reaction happened prior to the electrode process is the proton transfer reaction
[1]. This is attributed to the structure of polymer film changes and reduction of the
conductivity of polymer [2]. On the basis of above information, pH 4.5 was chosen for the
studies. In addition, we also optimized the enrichment time and enrichment potential having
effect on the current response. First, the current response was enhanced with the increase of
the enrichment time. As shown in Fig. S2C, the result indicated that the peak current raised
along with the accumulation time. After 180s, the current still maintained a steady value. The
accumulation time was chosen as 180 s. As shown in Fig. S2D, in the examined potential
range, the anodic peak current reached maximum value at 0.5 V. Besides, the enrichment
potential had effect on the current response. Moreover, the thickness of the polymer film also
had a certain influence. The current of LV tended to stable value when the electropolymerized
cycle was 10 cycles. So 10 scan cycles was chosen as the best polymerization cycle.
Table S1. An overview on recently reported nanomaterial-based methods for
electrochemical determination of levofloxacin.
Material Linear range(μM) LOD(μM) Specificity Ref.
PoAP/MWCNTs/GCE
MWCNT-SnO2/GC
MIP/G-Au/GCE
3.0-200
1.0-9.9
1-100
1
0.2
0.53
Satisfactor
y
Good
Excellent
[2]
[3]
[4]
DsDNA/GCE
ssDNA/SWCNT/gold E
MWNT-PAR/GCE
PoAP/GQDs/GCE
0.5-5
1.0-10
5.0-100
0.05-100
0.1
0.0752
0.4
0.01
-
-
Good
Satisfactor
y
[5]
[6]
[7]
This paper
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