A new voltammetric sensor based on reduced graphene oxide loaded flower-like Bi2O2CO3 film for sensitive determination of urapidil

Accepted Manuscript A new voltammetric sensor based on reduced graphene oxide loaded flower-like Bi2O2CO3 film for sensitive determination of urapidil

Yinghao Duan, Shuo Li, Sheng Lei, Yuanyuan Xu, Lina Zou, Baoxian Ye PII: DOI: Reference:

S1572-6657(18)30323-0 doi:10.1016/j.jelechem.2018.04.063 JEAC 4050

To appear in:

Journal of Electroanalytical Chemistry

Received date: Revised date: Accepted date:

24 February 2018 28 April 2018 28 April 2018

Please cite this article as: Yinghao Duan, Shuo Li, Sheng Lei, Yuanyuan Xu, Lina Zou, Baoxian Ye , A new voltammetric sensor based on reduced graphene oxide loaded flowerlike Bi2O2CO3 film for sensitive determination of urapidil. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Jeac(2017), doi:10.1016/j.jelechem.2018.04.063

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ACCEPTED MANUSCRIPT

A new voltammetric sensor based on reduced graphene oxide loaded flower-like Bi2O2CO3 film for sensitive determination of urapidil Yinghao Duan, Shuo Li, Sheng Lei, Yuanyuan Xu, Lina Zou*, Baoxian Ye*

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College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China

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* E-mail: [email protected]

ACCEPTED MANUSCRIPT Abstract: In this work, reduced graphene oxide loaded flower-like bismuth subcarbonate composite (Bi2O2CO3-rGO) has been successfully synthesized by a facile hydrothermal method. The prepared Bi2O2CO3-rGO as modification composite was

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applied to construct voltammetric sensor for the first time. The Bi2O2CO3-rGO

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modified glassy carbon electrode (Bi2O2CO3-rGO/GCE) exhibited highly sensitive

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response to urapidil. The electrochemical behavior of urapidil was studied in detail. Under optimum conditions, a lower detection limit (1.5×10-9 mol L-1) and wider linear

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range (5.0×10−9 mol L-1 - 4.0×10-6 mol L−1) were achieved by the proposed sensor.

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Finally, the proposed method was applied to the analysis of real sample, and the results showed applicable and reliable.

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Keywords: Urapidil; Bi2O2CO3; Graphene; Electrochemical sensor.

ACCEPTED MANUSCRIPT 1 Introduction Urapidil is a phenyl piperazine substituted uracil derivative. It has a highly selective blocker alpha1-adrenoceptor and a central hypotensive action [1]. The pharmacodynamics and therapeutic efficacy of urapidil demonstrated its reducing

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blood pressure without altering heart rate [2]. In 1981, Germany allowed to use

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urapidil hydrochloride. In 1992, the registration of urapidil was approved by China,

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and now, it has been widely used for hypertension in more than 20 countries. Therefore, it is necessary to develop sensitive analytical method for determination of

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urapidil. Although some conventional methods have been established for the

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determination of urapidil, such as fluorescence spectrophotometry [3], flow injection-indirect atomic absorption spectrometry (AAS) [4], flow injection

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chemiluminescence method (FI-CL) [5], high performance liquid chromatography

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(HPLC) [6, 7], reverse phase high-performance liquid chromatography (RP-HPLC) [8], they require relatively expensive equipment, technical expertise, and

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time-consuming. Compared with those methods, voltammetric methods can make up

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for these disadvantages. As far as we concerned, there were only two reports about the electrochemical determination of urapidil with detection limit reaching 3.8 × 10-8 mol L-1 and 2 × 10-8 mol L-1, respectively [9, 10]. So it is still interesting to develop a more sensitive, feasible electrochemical method for determination of urapidil. In recent years, various types of hierarchical composite have been fabricated by different approaches, and these show enhanced capacitance or photocatalytic performance via specific surface areas, unique structure. For example, a facile and

ACCEPTED MANUSCRIPT cost-effective approach to design and fabricate hierarchical Co2AlO4@MnO2 nanocomposite arrays on nickel foam for high-performance SCs [11]. Nanorods of layer-structure Li2MnO3 are successfully synthesized from stoichiometric mixture of MnO2 and LiOH·H2O [12]. Bismuth subcarbonate (Bi2O2CO3) is a typical member of

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the Aurivillius-related oxide family and consists of similar (Bi2O2)2+ layers and CO32−

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groups [13]. The Bi2O2CO3 has remarkable features such as highly conductivity for

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oxygen, biocompatibility, and nontoxicity [14]. Recently, Bi2O2CO3 has been used as supercapacitor material and photocatalysis material. For example, Sun et al. fabricated

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the 3D hierarchical Bi-based microsphere, which showed the outstanding specific

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capacitance [14]. One g-C3N4–Bi2O2CO3 composite with high visible light photocatalytic activity was prepared by Xiong’s group [15]. For further study, a

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method to control the structure of the material has been reported to improve the

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charge and ion-transfer efficiency of the pseudoactive material and to enhance the utilization of the pseudoactive material from the bulk [16]. So it’s easy to find that

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flower-like Bi2O2CO3 exhibited great potential considering its larger active surface

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area and enhanced conductivity in the electrochemical performance [17]. As far as we know, there has been no report related to application of flower-like Bi2O2CO3 on electrochemical sensors. Graphene is a two-dimensional carbon-based material which is known to exhibit high thermal conductivity, electric conductivity and excellent mechanical strength [18, 19]. All of these advantages make it appropriate in application of electrochemical sensors [20, 21]. In this paper, a facile one-pot hydrothermal reaction was used to

ACCEPTED MANUSCRIPT fabricate flower-like Bi2O2CO3 loaded on reduced graphene oxide (rGO) composite (Bi2O2CO3-rGO). Bi2O2CO3-rGO/GCE was constructed and used for the detection of urapidil.

The

response linear

range

and

detection limit

of

urapidil

at

Bi2O2CO3-rGO/GCE were superior to previous reports. The presented sensor was

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used for determination of urapidil in the real sample with satisfactory results.

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2 Experimental

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2.1 Reagents and apparatus

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All the reagents were analytical grade, including bismuth (III) nitrate pentahydrate (Bi(NO3)3.5H2O, Tianjin kemiou chemical reagent Co., Ltd., Tianjin,

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China), trisodium citrate dihydrate (C6H5Na3O7.2H2O, Tianjin guangfu chemical

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reagents factory, Tianjin, China), and urea (NH2CONH2, Shanghai Yuanye Biological

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Technology Co., Ltd., Shanghai, China). Graphite powder was obtained from Aladdin Co., Ltd., (Shanghai, China). The standard reagent of urapidil was purchased from the

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CRM/RM information center of China. The standard stock solution of urapidil (1.0×10-3 mol L-1) was prepared with ultrapure water and kept darkly under 4◦C.

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Urapidil sustained release tablets were purchased from Fuhehuaxing pharmaceutical group Co., Ltd., (Heilongjiang, China). In order to obtain the different pH values (3.0-8.0), 1 mol L-1 phosphate buffer solutions (PBSs) were prepared by mixing the stock solution (0.1 mol L-1 NaH2PO4, Na2HPO4 and H3PO4). All experiments were performed at room temperature and ultrapure water was used throughout experiments. A RST3000 electrochemical system (Zhengzhou Shiruisi Instrument Co. Ltd.

ACCEPTED MANUSCRIPT Zhengzhou,

China)

was

employed

in

electrochemical

performances.

All

electrochemical experiments were performed with a standard three-electrode electrochemical cell, using a saturated calomel reference electrode (SCE), a platinum wire auxiliary electrode and a bare or modified glassy carbon electrode (GCE, d =

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3mm). UV-vis spectroscopy was obtained from a Lambda 35 UV-vis spectrometer

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(Perkin Elmer, USA). The morphological characterization was studied by

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transmission electron microscopy (TEM, JEOL-2100 EX, Hiroshima, Japan). The morphology structure was characterized using scanning electron microscopy (SEM,

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JEOL JSM-6700, Japan). The crystalline properties of the modification materials were

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recorded by powder x-ray diffraction (XRD, Shimadzu) with Cu Kα radiation (λ=1.54056 Å). Infrared spectrograms were recorded on Infrared Spectrometer

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(Thermo Nicolet Coporation, Santa Clara, USA). High performance liquid

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chromatography was performed using a 1260 Infinity Quaternary LC System (Agilent Technologies Inc., Santa Clara, USA). The pH values were conducted by pHS-3C

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(Shanghai Techcomp Jingke Scientific Instruments, Shanghai, China).

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2.2 Preparation of Bi2O2CO3-rGO composites Bi2O2CO3-rGO composites were synthesized from one-step hydrothermal method following a previous recipe [22] with slight modifications. The GO was prepared with natural graphite powder by the Hummer’s method [23]. In a detailed preparation procedure, 50 mL of GO solution (2 mg mL-1) was ultrasonicated in ultrapure water for 2h to obtain a homogeneous suspension. For the synthesis of Bi2O2CO3-rGO composites, 50mL of GO suspension was mixed with 48 mg bismuth

ACCEPTED MANUSCRIPT nitrate pentahydrate, 88 mg trisodium citrate dihydrate, and 300 mg urea. Herein, urea was used not only as a material of Bi2O2CO3, but also a reducing agent for graphene oxide (GO). The mixture was stirred for 30 min at room temperature. Next, the mixture was transferred into a 100 mL Teflon-lined stainless autoclave and heated at

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180 °C for 12 h. Upon cooling to room temperature, the as-obtained precipitates were

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centrifuged for 10 min at room temperature. In order to remove unreacted impurities,

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precipitates were also suspended in ethanol and water for multiple wash by centrifuge steps. Following this, the product was dried in a vacuum oven at 60 °C overnight. For

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the same procedure above, respectively.

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comparison, Bi2O2CO3 and reduced graphene oxide (rGO) were synthesized following

2.3 Preparation of modified electrodes

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To begin with, bare glassy carbon electrode (GCE) was sequentially polished to a

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mirror-like surface with 0.3 μm alumina slurry, ultrasonic in anhydrous ethanol and ultrapure water, respectively. Bi2O2CO3-rGO suspension (1 mg mL-1) was prepared by

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ultrasonic in ultrapure water. Subsequently, 8μL of Bi2O2CO3-rGO suspension was

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cast on the fresh GCE surface and dried under the infrared lamp to prepare the Bi2O2CO3-rGO/GCE. For comparison, the rGO/GCE was also prepared with the similar procedure.

2.4 Analytical procedure In order to get a steady voltammogram, the prepared Bi2O2CO3-rGO/GCE was scanned between 0.3 V and 1.0 V with a scan rate of 0.1 V s-1 in 0.1 mol L-1 PBS (pH 3.0). Next, a certain amount of standard urapidil solution was added into the

ACCEPTED MANUSCRIPT electrochemical cell. Then, cyclic voltammogram (CV) or linear sweep voltammetry (LSV) was used to establish the analytical method. All data from CV and LSV experiments were acquired by scanning the potential between 0.3 V and 1.0 V. 2.5 Sample solution preparation

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Sample powder was obtained from the urapidil sustained release tablets, which

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was triturated in a mortar. Then, 0.2 g of the powder was dissolved with 30 mL

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ethanol and sonicated for 3 h. Following this, the solution was centrifuged for several times for ensuring complete extraction. After centrifugation, all supernatants from

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every step were merged together. Furthermore, the extraction solution was used as the

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3 Results and discussions

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detection sample.

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3.1 Characterization of Bi2O2CO3-rGO composites Fig.1A showed representative UV–vis spectrum of GO, rGO and Bi2O2CO3-rGO.

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GO (curve c) had a strong UV–vis absorption peak at 228 nm, which was in good

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agreement with π to π* transition of the aromatic C–C bond [24]. However, we couldn't find the apparent peaks of 228 nm in rGO (curve a) and Bi2O2CO3-rGO (curve b), which demonstrated that GO was completely reduced to rGO after the hydrothermal treatment [25]. In addition, the rGO and Bi2O2CO3-rGO exhibited an absorption peak at 263 nm. To further prove the construction of Bi2O2CO3-rGO, X-ray diffraction was conducted to investigate the crystal structure of Bi2O2CO3-rGO. It was compared in Fig.1B with GO and Bi2O2CO3. In Fig.1B (curve b), no apparent

ACCEPTED MANUSCRIPT characteristics diffracted peaks belonging to the GO was found, indicating that GO has been reduced successfully. All the diffraction peaks of the Bi2O2CO3-rGO can be found corresponding to the tetragonal phase of Bi2O2CO3 (JCPDS No. 41-1488) [26, 27]. Fig.1C showed the TEM of Bi2O2CO3-rGO, which showed flower-like pattern

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uniformly dispersing on rGO. Fig.1D displayed the SEM image of the flower-shaped

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Bi2O2CO3-rGO microspheres. The surface of Bi2O2CO3-rGO displayed a wrinkled

Fig.1

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morphology, confirming that the Bi2O2CO3 are wrapped in rGO.

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To understand the relative functional group of Bi2O2CO3-rGO composites, the

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characteristic peaks of Bi2O2CO3-rGO and Bi2O2CO3 were record on IR spectra (Fig.2). For every sample, the typical four internal vibration modes for CO32- groups

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were observed at v1 (1161 cm-1), v2 (846 cm-1), v3 (1456 cm-1 and 1396 cm-1) and v4

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(670 cm-1). The peak at 545 cm-1 belongs to the Bi-O bond, which was observed in both samples [28, 29]. In Fig.2A, the O-H stretching vibrations of absorption peaks

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were almost removed, which indicated successful reduction of GO by hydrothermal

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method. The absorption bands at 1560 cm-1 and 1142 cm-1 correspond to C=C (unoxidized skeletal graphite) and C-OH (hydroxyl). To sum up, Bi2O2CO3-rGO composites were successfully synthesized as expected by the hydrothermal treatment. Fig.2 3.2 The electrochemical characterization of Bi2O2CO3-rGO/GCE The surface features of the modified electrode were investigated using electrochemical impedance (EIS) in 5 mM [Fe(CN)6]3-/4- (containing 0.1 M KCl). In

ACCEPTED MANUSCRIPT the Nyquist plot of EIS, the semicircle diameter at higher frequencies corresponded to the charge transfer resistance (Rct) at electrode interface. As shown in Fig.3, the semicircle diameter of Bi2O2CO3-rGO/GCE (curve c) was markedly smaller than that of GCE (curve a) and rGO/GCE (curve b), indicating lower resistance and improved

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charge transfer ability of Bi2O2CO3-rGO.

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3.3 Electrochemical behavior of urapidil at sensors

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Fig.3

Fig.4 showed the cyclic voltammograms of urapidil (1.0×10-4 mol L-1) at

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different electrodes in PBS (pH 3.0). Obviously, only one anodic peak appereance at

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three electrodes illustrated a totally irreversible electrode reaction of urapidil. The peak potentials were 0.91 V at bare GCE (curve b), 0.83 V at rGO/GCE (curve d) and

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0.79 V at Bi2O2CO3-rGO/GCE (curve e). The negative shift of anodic peak potential

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could be attributed to the excellent electrocatalytic activity of rGO loaded Bi2O2CO3. What’s more, the peak current was slightly enhanced at rGO/GCE (curve d)

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comparing with that of bare GCE (curve b). However, the peak current of

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Bi2O2CO3-rGO/GCE (curve e) was nearly seven times more than that of bare GCE (curve b), which could be ascribed to the extraordinary electrocatalytic property of Bi2O2CO3-rGO/GCE. In conclusion, the Bi2O2CO3-rGO/GCE presented sensitive electrochemical sensing for urapidil, so we selected it as the voltammetric sensor for further study of urapidil. Fig.4

ACCEPTED MANUSCRIPT 3.4 The effect of solution pH Cyclic voltammetry was conducted to test the effect of pH on the electrochemical response of urapidil (1.0×10-4 mol L-1) at the Bi2O2CO3-rGO/GCE, which was studied in PBS (0.1 mol L−1) with pH values between 3.0 and 8.0. As

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shown in Fig.5, when the pH values increased, the peak currents changed slightly and

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the oxidation peak potentials of urapidil shifted negatively due to the proton

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participation in the electrode process. Meanwhile a linear relationship was observed between peak potentials and pH with a linear equation: Epa (V) = −0.036 pH + 0.895

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(R2=0.987). The slope value was close to half of the theoretical value of -0.059 V /

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pH. It was in good agreement with the result that the transferred protons and electrons in the oxidation process were in a ratio of 1:2. The highest response of peak current

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was clearly observed at pH 3.0 in Fig.5. And considering of the peak shape, pH 3.0 of

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0.1 M PBS was selected for the further experiments. Fig.5

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3.5 Influence of scan rate

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CV was used to test the influence of scan rate on the electrochemical response of urapidil (1.0×10-4 mol L-1). When the scan rates gradually increased from 0.02 to 0.3 V s-1, the anodic peak currents increased (Fig.6A). In addition, it showed that the peak potentials shift positively as the increase of scan rates. There was a linear equation ipa (10-4A) = 28.652v (V s−1) + 0.396 (R2=0.990) to show the relationship between ipa and v (Fig.6B), indicating that the electrode process of urapidil was mainly controlled by adsorption [30]. Similarly, the line relationship between Epa and lnv was obtained,

ACCEPTED MANUSCRIPT which was expressed as Epa (V) = 0.0255 lnv + 0.853 (R2=0.995) (Fig.6C). According to Laviron’s theory [31] for an irreversible electrode process mainly controlled by adsorption, the Ep and lnv follows the equation: ,

Ep(V )  E 0 

RT RTk s RT ln  ln v nF nF nF

(1)

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Here, E0′ refers to the formal standard potential and ks is the standard

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heterogeneous reaction rate constant, n means the transfer electron number, α is

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charge transfer coefficient, v, R, T and F express their usual meaning. Based on the slope of equation, the n and α were calculated as 2 and 0.5, respectively. According to

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the above data, a reasonable reaction mechanism of urapidil was proposed and shown

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in Scheme 1. Fig.6

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3.6 Chronocoulometry studies

Scheme 1

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As mentioned above, the electrode process was mainly controlled by adsorption. Therefore, single potential step chronocoulometry was performed to calculate the

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saturated adsorption capacity (Γ*) of urapidil at the Bi2O2CO3-rGO/GCE surface. As

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shown in Fig.7A, the potential was stepped between 0.3 V and 1.0 V and the Q-t curves were obtained in a blank PBS (Fig.7A, curve a) and 1.0×10-4 mol L-1 urapidil solution (Fig.7A, curve b), respectively. Fig.7B performed the corresponding linear relation of Q–t1/2 plots and the data were extracted from Fig.7A. The relationship between Q and t1/2 was expressed as following equations: Q (10-5C) = 1.243 t1/2 + 1.902 (R2 = 0.998) and Q (10-5C) = 4.989 t1/2 + 3.827 (R2= 0.998). The curve a and curve b have large difference of intercept and little difference of slope. These data

ACCEPTED MANUSCRIPT demonstrated that the electrode process of urapidil was mainly controlled by adsorption accompanying little diffusion. Based on the following Anson equation [32], Qdl is the double-layer charge, Qads is the Faradaic charge due to the oxidation of adsorbed urapidil, A, D and Γ* are the surface area of the electrode, the diffusion

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coefficient and the saturated adsorption capacity (Γ*) of urapidil, respectively. Qads

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was 1.925×10-5 C and the saturated adsorption capacity (Γ*) was calculated to be

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1.412×10-9 mol cm-2 with the equation Qads = nFAΓ* [33]. According to the slope of

cm2 s-1.

2nFAC ( Dt )1/ 2

 1/ 2

 Qdl  Qads

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Q

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curve b in Fig.7B, the value of diffusion coefficient (D) was calculated as 1.051×10-9

(2)

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Fig.7

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3.7 Calibration curve, repeatability, stability The linear sweep voltammetry (LSV) was conducted to establish the calibration

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curve of urapidil under optimized conditions. Fig.8A showed the superimposed LSV curves of urapidil with various concentrations in PBS (pH 3.0). The oxidation peak

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currents increased linearly with urapidil concentrations in the range of 5.0×10-9 4.0×10-6 mol L-1 (Fig.8B). The linear regression equation was i (10-6A) = 6.425 C (10-6 mol L-1) + 1.981 (R2=0.996) with detection limit of 1.5 × 10-9 mol L-1 (S/N = 3). The detection parameters were compared with previous relevant reports in Table.1, indicating a feasible method for determination of urapidil with higher sensitivity and wider linear range.

ACCEPTED MANUSCRIPT The reproducibility and stability of the sensor was tested with LSV in 1×10-6 mol L-1 urapidil solution. Under the same conditions, the reproducibility of the Bi2O2CO3-rGO/GCE was evaluated by using five parallel prepared sensors and the relative standard deviation (RSD) of 2.1% was gained. Moreover, one sensor used in

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five independent measurements was performed to calculate a value of RSD (1.9%).

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The results proved that the sensor had a satisfying reproducibility. After one

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Bi2O2CO3-rGO/GCE was stored for two weeks at room temperature, the response peak current of urapidil only reduced 3.2% comparing with its initial value, indicating

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the good stability of the sensor.

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Fig.8 Table 1 3.8 Interference studies

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For the analytical application of the proposed method, various possible

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interfering species were evaluated, with a fixed urapidil concentration of 1.0 × 10-6 mol L-1. The tolerance limit for a foreign species was taken as the largest amount

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yielding a relative error <±5% for the current response of urapidil. The experiment

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results (Fig.9) showed that no interference was aware for following inorganic ions and organic compounds: 100-fold concentration of Al3+, Ca2+, Mg2+, Cu2+, Zn2+, glucose, starch and 10-fold concentration of ascorbic acid and 50-fold concentration uric acid. The results indicated that the present method was adequate for the determination of urapidil in real samples. Fig.9

ACCEPTED MANUSCRIPT 3.9 Real sample analysis In order to evaluate the feasibility of the proposed method, it was employed for determination of the content of urapidil in urapidil sustained release tablets. The pretreatment of samples were described in section 2.5. Three parallel samples were

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analyzed with RSD of 3.2% (Table 2). After each determination, some standard

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urapidil was added in the three samples, respectively, and the total content of urapidil

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were determined again to calculate the recovery (Table 2). The results revealed the recoveries in range of 98.89% - 104.09% and RSD from 1.4% to 2.6%. For testing the

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accuracy of proposed method, the same samples were analyzed using HPLC method

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and the results were listed in Table 2 too. The contents obtained from the proposed method and HPLC method were compared using t-test under 95% confidence levels

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with no significant difference between them.

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In order to evaluate the validity of the new sensor in biological samples, human blood serum was selected as real sample. There was no distinct signal of urapidil was

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observed in original sample. For evaluating the veracity, the recoveries were

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calculated afterwards by adding some standard urapidil solutions into the sample and the results were listed in Table 3. Table 2

Table 3

4 Conclusions In conclusion, Bi2O2CO3-rGO composite was successfully synthesized via a facile one-pot hydrothermal reaction. It was the first report on the use of flower-like

ACCEPTED MANUSCRIPT Bi2O2CO3-rGO as modification film for the construction of voltammetric sensor. The electrochemical behavior of urapidil at Bi2O2CO3-rGO/GCE was studied in detail. A new voltammetric method for determination of urapidil was established with wider detection linear range of 5.0×10-9 - 4.0×10-6 mol L-1 and lower detection limit of

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1.5×10-9 mol L-1 (S/N=3). The applicability of the sensor was also proved for highly

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selective determination of urapidil in real sample with satisfactory results. This new

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nanocomposite provided a promising platform for the development of biosensor and electrochemical sensor. Our research could provide a valuable reference for the

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application of other bismuth oxide based composites in electrochemical sensors.

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Acknowledgements

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This work was supported by the National Natural Science Foundation of China

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(Grant no. 21575130; U1504216) and Startup Research Fund of Zhengzhou

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University (Grant no. 1511316006)

ACCEPTED MANUSCRIPT References [1] van Zwieten PA, Blauw GJ, van Brummelen P, Pharmacological profile of antihypertensive drugs with serotonin receptor and alpha-adrenoceptor activity, Drugs 40(suppl. 4) (1990) 1-8.

PT

[2] Dooley M, Goa KL, Urapidil-A reappraisal of its use in the management of

RI

hypertension, Drugs 56 (1998) 929-955.

SC

[3] Y. Wei, D. Ma, X. Li, The fluorescence spectra of urapidil and its determination, Chin. J. Anal. Lab. 23 (2004) 42-44.

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[4] Y. Li, H. Lang, Y. Wei, W. Zhang, Determination of urapidil by flow-injction

MA

indriect atomic absorption spectrometry , Chin. J. Anal. Lab. 22 (2003)16-18. [5] H.Y. Lang, Y.R. Li, W.P. Zhang, X.J. Zhang, Y.H. Shen, Determination of urapidil

D

by flow injection chemiluminescence . Chem. J. Chinese Univ. 24 (2003)

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618-620.

[6] K. Zech, R. Huber, Determination of urapidil and its metabolites in human serum

CE

and urine: comparison of liquid—liquid and fully automated liquid—solid

AC

extraction，J. Chromatogr. 353 (1986) 351-360. [7] D. Cai, Q. Zhang, HPLC Analysis of Urapidil in Pharmaceutical Dosage Form， Asian J. Chem. 24 (2012) 315-318. [8] Y. Liu, RP-HPLC determination of urapidil hydrochloride in injections, Chin. J. New Drugs 12 (2003) 930-932. [9] L. Zheng, J. Song, Voltammetric behavior of urapidil and its determination at multi-wall carbon nanotube paste electrode, Talanta 73 (2007) 943-947.

ACCEPTED MANUSCRIPT [10] K. Li, Y. Li, L. Yang, W. Wang, Sensitive determination of urapidil at an electrochemically pretreated glassy carbon electrode by linear sweep voltammetry, Anal. Methods 6 (2014) 6548-6554. [11] F. Li, H. Chen, X. Liu, Sh. Zhu, Low-cost high-performance asymmetric

PT

supercapacitors based on Co2AlO4@MnO2 nanosheets and Fe3O4 nanoflakes, Can.

RI

J. Mater. Chem. A 4 (2016) 2096-2104.

SC

[12] W. Xu, Zh. Jiang, Q. Yang, W. Huo, Y. Li, Approaching the lithium-manganese oxides' energy storage limit with Li2MnO3 nanorods for high-performance

NU

supercapacitor, Nano Energy 43 (2018) 168-176.

MA

[13] P. Aylor, S. Sundek, V. Lopata, Structure, spectra, and stability of solid bismuthcarbonates, Can. J. Chem. 62 (1984) 2863-2873.

D

[14] J. Sun, J. Wang, Z. Li, Z. Yang, S. Yang, Controllable synthesis of 3D

PT E

hierarchical bismuth compounds with good electrochemical performance for advanced energy storage devices, RSC Adv. 5 (2015) 51773-51778.

CE

[15] M. Xiong, L. Chen, Q. Yuan, J. He, S.L. Luo, C.T. Au, S.F. Yin, Facile

AC

fabricationand enhanced photosensitized degradation performance of the g-C3N4–Bi2O2CO3 composite, Dalton Trans. 43 (2014) 833-8337. [16] Sh. Zhu, L. Li, J. Liu, H. Wang, T. Wang, Y. Zhang, Structural directed growth of ultrathin parallel birnessite on β ‑ MnO2 for high-performance asymmetric supercapacitors, ACS Nano 12 (2018) 1033−1042. [17] J. Ma, S. Zhu, Q. Shan, S. Liu, Y. Zhang, F. Dong, H. Liu, Facile synthesis of flower-like

(BiO)2CO3@MnO2

and

Bi2O3@MnO2

Nanocomposites

for

ACCEPTED MANUSCRIPT supercapacitors, Electrochim. Acta 168 (2015) 97-103. [18] K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A.A. Firsov, Electric field effect in atomically thin carbon films, Science 306 (2004) 666-669.

PT

[19] C. Wu, Q. Cheng, K. Wu, G. Wu, Q. Li, Graphene prepared by one-pot solvent

RI

exfoliation as a highly sensitive platform for electrochemical sensing, Anal. Chim.

SC

Acta 825 (2014) 26-33.

[20] H. Li, K. Sheng, Z. Xie, L. Zou, Highly sensitive determination of hyperin on

NU

poly(diallyldimethylammonium chloride)-functionalized grapheme modified

MA

electrode, J. Electroanal. Chem. 776 (2016) 105–113. [21] Y. Gao, L. Wang, Y. Zhang, S. Li, B. Ye, Greenly synthesized graphene with

D

L-glutathione modified electrode and its application towards determination of

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rutin, RSC Adv. 6 (2016) 94024–94032. [22] F. Dong, W. K. Ho, S. C. Lee, Z. B. Wu, M. Fu, S. C. Zou and Y. Huang,

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Template-free fabrication and growth mechanism of uniform (BiO)2CO3

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hierarchical hollow microspheres with outstanding photocatalytic activities under both UV and visible light irradiation, J. Mater. Chem. 21 (2011) 12428-12436. [23] S. Bose, T. Kuila, M.E. Uddin, N.H. Kim, A.K.T. Lau, J.H. Lee, In-situ synthesis and

characterization

of

electrically

conductive

polypyrrole/graphene

nanocomposites, Polymer 51 (2010) 5921-5928. [24] L. Zhang, J. Zhang, Z. Jiang, S. Xie, M. Jin, X. Han, Q. Kuang, Z. Xie, L. Zheng, Facile syntheses and electrocatalytic properties of porous Pd and its alloy

ACCEPTED MANUSCRIPT nanospheres, J. Mater. Chem. 21 (2011) 9620-9625. [25] E.H. Joo, T. Kuila, N.H. Kim, J.H. Lee, S.A. Kim, E.G. Park, U.H. Lee, Electrochemically Preparation of functionalized graphene using sodium dodecyl benzene sulfonate (SDBS), Adv. Mater. 747 (2013) 246-249.

subcarbonate

nanotubes/graphene

sheet

with

highly

efficient

RI

bismuth

PT

[26] Y. Tang, C. Yang, K. Li, F. Jing, R. Liu, D. Wu, J. Jia, Leaf-like hybrid of

SC

photocatalytic activities, J. Colloid Interf. Sci. 491 (2017) 273-278. [27] X. Cui, X. Yu, L. Hou, A. Gagnoud, Y. Fautrelle, R. Moreau, Z. Ren, X. Lu, X. Li,

NU

Bismuth-based compounds crystals growth on graphene with various degrees of

MA

oxidation, J. Alloy Compd. 684 (2016) 21-28.

[28] F. Dong, S. C. Lee, Z. B. Wu, Y. Huang, M. Fu, W. K. Ho, S. C. Zou and B.

D

Wang, Rose-like monodisperse bismuth subcarbonate hierarchical hollow

PT E

microspheres: One-pot template-free fabrication and excellent visible light photocatalytic activity and photochemical stability for NO removal in indoor air,

CE

J. Hazard. Mater 195 (2011) 346-354.

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[29] Y. Zhang, D. Li, Y. Zhang, X. Zhou, S. Guo, L. Yang, Graphene-wrapped Bi2O2CO3 core-shell structures with enhanced quantum efficiency profit from an ultrafast electron transfer process, J. Mater. Chem. A 2 (2014) 8273-8280. [30] R.S. Nicholson, I. Shain, Theory of stationary electrode polarography. Single scan and cyclic methods applied to reversible, irreversible, and kinetic systems, Anal. Chem. 36 (1964) 706-723. [31] E. Laviron, General expression of the linear potential sweep voltammogram in

ACCEPTED MANUSCRIPT the case of diffusionless electrochemical systems, J. Electroanal. Chem. 101 (1979) 19-28. [32] F.C. Anson, Application of potentiostatic current integration to the study of the adsorption of cobalt (III)-(ethylenedinitrilo(tetraacetate) on mercury electrodes,

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Anal. Chem. 75 (1969) 313-315.

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[33] A.J. Bard, L.R. Faulkner, Electrochemical Methods: Fundamentals and

AC

CE

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MA

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Applications, John Wiley & Sons, Inc, New York, 2001.

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Table 1 Comparision of several methods for detection of urapidil (The cited concentration unit had been converted to unified standard: mol L-1).

Linear range (mol L−1)

Fluorescence Spectrophotometry

3.3×10-7–1.6×10-5

AAS

Detection limit ( mol L−1)

Reference

-

3

1.2×10-5–2.5×10-4

-

4

FI-CL

5.1×10-7–2.5×10-4

2.6×10-8

5

HPLC

2.5×10-5–4.1×10-4

-

7

RP-HPLC

2.5×10-4–2.1×10-3

-

8

MWCNT/CPE

5.0×10-8–2.0×10-6

3.8×10-8

9

2.0×10-8–5.0×10-6

2.0×10-8

10

5.0×10-9–4.0×10-6

1.5×10-9

This work

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Bi2O2CO3-rGO/GCE

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Method

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Table 2 Determination results of urapidil in urapidil sustained release tablets by LSV and HPLC.

HPLC Found a

Recovery

RSD

Found a

(10-6mol L-1)

(10-6mol L-1)

(%)

(%)

(10-6mol L-1)

0

1.264

3.2

1.250

1

2.357

104.09

2

3.228

2.6

3

4.357

102.18

1.4

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Average value of three repeated measurements.

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a

98.89

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5

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Added a

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sample(μL)

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LSV

2.1

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Table 3

Found c

Recovery

RSD

(10-6mol L-1)

(10-6mol L-1)

(%)

(%)

Human

1

1.003

100.3

1.7

blood

2

1.985

99.25

2.0

serum a

3

2.940

2.3

98.00

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Sample

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Added b

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Determination results of urapidil in human blood serum.

0.5 mL human blood serum was mixed with 9.5 mL pH 3.0 PBS.

b

10μL or 20μL or 30μL urapidil solution (1×10-3mol L-1) was added to the mixed solution.

c

Average value of three repeated measurements.

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a

ACCEPTED MANUSCRIPT Fig.1. (A) UV-vis absorption spectra of GO (c), rGO (a) and Bi2O2CO3-rGO (b). (B) XRD patterns of GO (a), Bi2O2CO3-rGO (b) and Bi2O2CO3 (c). (C) The TEM of Bi2O2CO3-rGO. (D) The SEM of Bi2O2CO3-rGO.

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Fig.2. FTIR spectra of Bi2O2CO3-rGO (A) and Bi2O2CO3 (B).

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Fig.3. Nyquist plots of 5 × 10-3 moL L-1 Fe(CN)64-/3- (containing 0.1 mol L-1 KCl ) at bare GCE (a),

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rGO/GCE (b) and Bi2O2CO3-rGO/GCE (c). Performed frequency range: 1.0 MHz - 0.01 Hz.

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Fig.4. Cyclic voltammograms of 1.0 × 10-4 mol L-1 urapidil in 0.1 mol L-1 PBS (pH 3.0) at bare GCE (b), rGO/GCE (d) and Bi2O2CO3-rGO/GCE (e), respectively. Blank voltammograms of bare

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GCE (a), Bi2O2CO3-rGO/GCE (c), scan rate: 0.1V s-1.

Fig.5. (A) Cyclic voltammograms of urapidil (1 × 10-4 mol L-1) at Bi2O2CO3-rGO/GCE with

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different pH (a-f: 3.0, 4.0, 5.0, 6.0, 7.0, 8.0). (B) The relationship between peak potentials and pH,

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scan rate: 0.1 V s-1.

Fig.6. (A) Cyclic voltammograms of urapidil (1 × 10-4 mol L-1) in 0.1 mol L-1 PBS (pH 3.0) with different scan rates (a-g: 0.02, 0.04, 0.08, 0.10, 0.15, 0.20, 0.30 V s−1). the peak currents versus v. (C) The relationship of Ep versus lnv.

(B) The relationship of

ACCEPTED MANUSCRIPT Fig.7. (A) Chronocoulometric curves obtained in the absence (a) and presence (b) of urapidil (1 × 10-4 mol L-1) in 0.1 mol L-1 PBS (pH 3.0). (B) The relationship of Q against t1/2.

Fig.8. (A) The LSV curves of urapidil in 0.1 mol L-1 PBS (pH 3.0) with different concentrations

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(a-h: 5 × 10-9, 3 × 10-8, 8 × 10-8, 4 × 10-7, 7 × 10-7, 1 × 10-6, 2 × 10-6, 3 × 10-6, 4 × 10-6 mol L-1). (B)

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The relationship of the peak currents versus C. Scan rate: 0.1 V s-1, open-circuit accumulation

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time: 350 s.

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Fig.9. Column chart the oxidation peak current of urapidi (1 × 10-6) with presence of some normal

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anions and organic compounds.

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Scheme1. The proposed oxidation mechanism of urapidil.

ACCEPTED MANUSCRIPT Highlights  Facile and one-step synthesis of Bi2O2CO3-rGO composite.  The flower-like Bi2O2CO3-rGO as modification composite was applied to construct voltammetric sensor for the first time.

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 Bi2O2CO3-rGO/GCE presented the excellent electrocatalytic property in the

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electrochemical response of urapidil.

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 A new voltammetric method for determination of urapidil was established with

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wider detection linear range and lower detection limit.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9