Contents lists available at ScienceDirect

Ultrasonics - Sonochemistry

journal homepage: www.elsevier.com/locate/ultson

Sonochemical synthesis of bismuth(III) oxide decorated reduced grapheneoxide nanocomposite for detection of hormone (epinephrine) in human andrat serum

Shaktivel Manavalana, Umamaheswari Rajajia, Shen-Ming Chena,⁎, Mani Govindasamya,S. Steplin Paul Selvinb, Tse-Wei Chena,c, M. Ajmal Alid, Fahad M.A. Al-Hemaidd, M.S. Elshikhd

a Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwanb PG and Research Department of Chemistry, Bishop Heber College, Tiruchirappalli 620017, Tamil Nadu, Indiac Research and Development Center for Smart Textile Technology, National Taipei University of Technology, Taipei, Taiwand Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia

A R T I C L E I N F O

Keywords:AdrenalineNeurotransmitterMetal oxide nanoparticleElectrocatalystReduced graphene oxide

A B S T R A C T

Herein, we report an efficient electrochemical sensor strategy for determination of epinephrine based on Bi2O3

nanoparticle decorated reduced graphene oxide nanocomposite (Bi2O3@RGO). The Bi2O3@RGO was preparedby simple ultrasonic method and then it’s morphological and crystal structure aspects were well characterized byphysiological instruments. The electrode-electrolyte interfacial properties were examined to ensure the catalyticability of composite sensing towards EP. The composite was deposited on the multi-conventional screen-printedelectrode and was found to be desirable performance toward EP oxidation. The amperometric EP sensing ex-hibited good reproducible and sensitive which able to detect as low as concentration of 2.14 nM. Furthermore,good reproducibility, long-term stability and repeatability were obtained from the electrode in experiment.Moreover, the EP sensing method was successfully applied in human and rat blood serum, the recoveries werevalidated by HPLC method. It indicates the reliability of the method in practical analysis.

1. Introduction

Epinephrine (EP), a neurotransmitter which plays a major func-tional role in the mammalian central nerves and hormone system [1,2].It is produced by the adrenal glands and certain neurons in situation ofphysiological stress or low blood sugar level [3]. it is also known asadrenaline, play a significant role during the physical or mental stressand act as “fight or flight response” during a series of process of sym-pathetic nervous system (SNS) [4,5]. In pharmaceutical, epinephrine isused as drug in the treatment of cardiothoracic surgery such as heartattack, blood pressure, and great vessels [6,7]. However, the excessivesecretion or dosage of epinephrine may lead to serious effects includingParkinson’s disease [8], multiple sclerosis [9], and upregulation ofblood pressure, heart rate, immune system, and glycogen metabolism[10,11]. Therefore, the rapid and sensitivity determination of epi-nephrine is of great important to diagnosis and regulating medicine. Sofar, various methods have been in the use of practical such as spec-trophotometry, capillary electrophoresis and chromatography. How-ever, these methods were retarded by expensive, time- consuming, and

needs skill to operate [12–17]. Therefore, much attention has beenfocused on the electrochemical methods for determination of epi-nephrine that was relatively simple, low-cost, and sensitive.

Recently, Bismuth oxide nanoparticles (Bi2O3) has been paid muchattention to semiconductor materials among the bismuth(III) basedmaterials because of its simplest and unique features [18]. It existsdifferent crystalline phase of Bi2O3 nanoparticles includes α, β, γ, δ, andω (monoclinic, tetragonal, BCC, cubic, and triclinic) e.g., Camacho-Lopez et al. have reported different crystal phase of Bi2O3 nanoparticles[19,20]. So far, many researchers synthesized Bi2O3 nanoparticles indifferent morphologies by various methods such as, chemical deposi-tion, hydrothermal, microwave and ultrasonic method [21,22]. Amongthese, ultrasonic method has more advantages such as low cost synth-esis, simple, facile and eco-friendly to the nature. Bi2O3 is a low bandgap material, have extensive properties such as a large energy bandgap, high refractive index, dielectric permittivity, photo luminescence,photo and electrical conductivity [23]. These features of Bi2O3 nano-particles were utilized in several applications of optical, super-conductors, energy storage materials, oxide ion conductivity, catalysts,

https://doi.org/10.1016/j.ultsonch.2018.10.008Received 21 August 2018; Received in revised form 3 October 2018; Accepted 5 October 2018

⁎ Corresponding author.E-mail address: smchen78@ms15.hinet.net (S.-M. Chen).

Ultrasonics - Sonochemistry 51 (2019) 103–110

Available online 09 October 20181350-4177/ © 2018 Elsevier B.V. All rights reserved.

T

and sensors. Unfortunately, the electrocatalytic activity of Bi2O3 is re-latively poor due to the recombination of photogenerated electron/holepairs. In case of Bi2O3 nanoparticles combine with any elementaldoping, conducting polymer, and carbon based materials [24] there isan enhancement in the efficiency of material.

The reduced graphene oxide (RGO) is a one of the carbon materialwith sp2 hybridization and having two dimensional (2D) morphology[25,26]. The RGO is a good conductive material, have been researchedfor many properties, such as optical, mechanical, thermal, carrier mo-bility, and electronic conductivity [27–31]. Therefore, it has been ef-fectively utilized in the field of solar cells, energy storage material, li-thium ion batteries, photo catalyst, and sensors. Many researchers havebeen reported that metal oxide doped RGO nanocomposite are goodelectrocatalytic active material [31–40].

Now, the objective of the work is that to prepare Bi2O3@RGO na-nocomposite through simple ultrasonic method. The influence of thenanocomposite modified screen-printed electrode (SPCE) toward thedetermination of epinephrine were inspected by cyclic voltammetryand amperometric method. Further, this strategy was applied in thedetermination of epinephrine in the human and rat blood serum sam-ples and schematically represented in Scheme 1.

2. Experimental

2.1. Materials and Reagents

The materials such as graphite and bismuth(III) nitrate pentahy-drate (Bi(NO3)3·5H2O) were purchased from Sigma Aldrich and usedwithout further purification. The Reagents such as epinephrine, ser-otonin (5-HT), dopamine (DA), uric acid (UA), ascorbic acid (AA), folicacid (FA), K+,Cl−, and Fe(CN)63−/4− were of analytical grade and usedas received. For supporting electrolyte, sodium dihydrogen phosphateand disodium hydrogen phosphate were used to prepare 0.05M ofphosphate buffer (pH 7.0). Human and rat blood serum samples wereacquired and also experimented by as per the laws and institutionalguidelines of Chang Gung University, Taiwan.

2.2. Instrumentation

The samples were all synthesized by 40 kHz ultrasonic instrument(DC150H ultrasonic cleaner; delta). The surface, crystal phase, andstructural composition of samples were characterized using X-ray dif-fraction pattern (XRD, PAN analytical, Nerthlands), high resolution X-ray proton emission (HR-XPS, Thermo ESCALAB 250), field emission

scanning electron microscopy (FE-SEM, JSM-7610F), high resolutiontransmission electron microscopy (HR-TEM, JEM-2100F, Tokyo) andenergy dispersive X-ray analysis (EDX, HORIBA EMAXX-ACT). Theimpedance studies were observed by electrochemical impedance spec-troscopy (EIS, EIM6ex Zahner, Germany). For electrochemical studies;cyclic voltammetric (CV, CHI1205A) and amperometric (i-t, PINE in-struments, USA). A conventional three electrode cell system carryingmodified SPCE (Electrode surface area= 0.018 cm2), saturated Ag/AgCl, and Pt wire were used as a working, reference and counterelectrode.

2.3. Preparation of GO and synthesis of Bi2O3@RGO

Graphite oxide (GO) was prepared from oxidation of graphite usingHummers’ method and exfoliated to graphene oxide through 2 h ofultrasonication method [41]. The GO dispersion was underwent cen-trifugation for 30min at 6000 rpm to remove unexfoliated graphiteoxide. To this aqueous GO dispersion (25mg in 25mL), about 3 g of Bi(NO3)3·5H2O was added and placed into an ultrasonic bath at the op-erating frequency of 40 kHz and subsequently treated for 2 h. After, thesediment that contains Bi2O3@RGO was separated, washed with waterand ethanol and then freeze-dried. 1 mgmL−1 dispersion of Bi2O3@RGO was prepared in water mixture (1:1, V/V) via ultrasonication for20min. Then, the procedure was repeated to prepare Bi2O3 and RGOfor control studies (Scheme 1).

2.4. Fabrication of Bi2O3@RGO nanocomposite modified electrode

Under optimized condition (Fig. S1), about 8 µL of Bi2O3@RGOdispersion was drop casted on the working electrode surface and driedat room temperature. RGO/SPCE, Bi2O3/SPCE and unmodified SPCEwere prepared to perform control experiments.

3. Results and discussions

3.1. Structural properties of Bi2O3@RGO nanocomposite

The XRD pattern of RGO revealed a characteristic peak at 2θ of26.53° which can be indexed to (0 0 2) planes of RGO (Fig. 1A). InFig. 1A, the XRD curve of Bi2O3@RGO showed several diffraction peaksat 28.07°, 30.46°, 31.90°, 32.80°, 46.32°, 47.03°, 54.36°, 55.59°, 57.88°,74.63°, and 86.71° which are matching to the (2 0 1), (2 1 1), (0 0 2),(2 2 0), (2 2 2), (4 0 0), (2 0 3), (4 2 1), (2 1 3), (4 2 3), and (6 2 2) phasesof Bi2O3. The phase of Bi2O3 is consistent to its cubic phase structure

Scheme 1. Synthesis of Bi2O3@RGO and its electrochemical sensing toward epinephrine.

S. Manavalan et al. Ultrasonics - Sonochemistry 51 (2019) 103–110

104

with JCPDS labeled number of 78–1793 [42]. The XRD trace of RGO(24.53°) was appeared in the XRD pattern of Bi2O3@RGO; Hence, theformation of RGO, Bi2O3 and Bi2O3@RGO were conformed in the XRD

analysis.The XPS is carried out to analyze the surface composition and oxi-

dation states of the elements of Bi2O3@RGO nanocomposite (Fig. 1Band C). The Fig. 1B displays the over-all XPS survey signals of C, O, andBi elements, which are well similar accordance with the EDX reports.The high magnification XPS spectrum of C 1 s elements reveals onesharp trace at the binding energy of 285.95 eV (see Fig. S2A inSupplementary information). The high magnification of O 1 s displaysone peak at the binding energies of 532.35 eV (see Fig. S2B inSupplementary information), which refers that the oxidation state of Oin this composite is−2. On the other hand, the high magnification of Bi4f spectrum displays the peaks at 158.93 and 164.34 eV correspond to4f of Bi3+, respectively (Fig. 1C). Overall, the XPS results are in ac-cordance with previous report and further strongly prove that the na-nocomposite has been successfully obtained.

Next, the surface morphology of the nanocomposite was studied byFE-SEM (Fig. 2). The FE-SEM image of Bi2O3 display aggregated na-noparticle (Fig. 2A). However, the FE-SEM image of Bi2O3@RGOcomposite showed the presence of aggregated Bi2O3 nanosphere welldistributed on the sheets of RGO. Fig. 2C shows the attraction betweenthe Bi2O3 nanosphere and RGO in the Bi2O3@RGO nanocomposite. Agood electrostatic-attractive interaction between RGO sheets and Bi2O3

nanospheres are possibly stabilizing them in the composite form. TheEDX spectrum of Bi2O3@RGO revealed signals for the expected ele-ments, such as carbon, oxygen, and bismuth signals with weight

Fig. 1. The XRD (A), HR-XPS overall survey of Bi2O3@RGO (B), and high resolution of Bi 4f (D).

Fig. 2. FE-SEM images of Bi2O3 (A), Bi2O3@RGO nanocomposite lower (B) and higher magnification (C). The EDX spectrum (D) and quantitative analysis (inset). TheHR-TEM images of Bi2O3 (E), and Bi2O3@RGO (F).

Fig. 3. EIS curves of Bi2O3/SPCE (a), RGO/SPCE (b), and Bi2O3@RGO/SPCE (c)modified SPCEs in 0.1M KCl containing 5mMK[Fe(CN)6]3−/4−.

S. Manavalan et al. Ultrasonics - Sonochemistry 51 (2019) 103–110

105

percentages of 24.8, 12.7, and 62.5 eV respectively (Fig. 2D). The ele-mental mapping of the composite displays the homogeneous distribu-tion of C, O, and Bi in the Bi2O3@RGO (see Fig. S3A–C inSupplementary file).

The HR-TEM image of Bi2O3 and Bi2O3@RGO nanocomposite areshown in Fig. 2E and F. The HR-TEM image of Bi2O3 display the spherelike structure nanoparticles (Fig. 2E), while the FE-SEM image of RGOis featured with the characteristic sheet-like morphology (see Fig. S4Ain Supplementary file). The HR-TEM image of Bi2O3@RGO reveal thedistribution of several nanoparticles that are decorated by wrinkledsheets, as expected for Bi2O3@RGO nanocomposite. Consistent with FE-SEM results, HR-TEM analyses is also indicates the successful formationof composite (Fig. 2F). The selected area diffraction (SAED) patterndisplay the clear bright spots forming a well-defined rings and

consistent with the XRD pattern of Bi2O3@RGO (see Fig. S4B inSupplementary file).

3.2. The interfacial property of modified electrode

To look at electrodes interfacial property behavior, we examinedelectrochemical impedance spectroscopy (EIS). The Fig. 3 displays theEIS curves of RGO/SPCE (a), Bi2O3/SPCE (b), and Bi2O3@RGO/SPCE(c) in 0.1 M KCl containing 5mM Fe (CN)63−/4− (frequency 0.1 Hz to100 KHz; amplitude=5mV). The Randles equivalent circuit modelwas used to fit the experimental data here Rs, Zw, Rct and Cdl are standsfor the ohmic resistance of electrolyte (Rs), Warburg impedance (Zw),electron transfers resistance (Rct), and a double layer capacitance (Cdl).Bias potential= 0.25 V, frequency 0.1 Hz to 100 KHz, and

Fig. 4. (A) CVs obtained at unmodified SPCE (a), Bi2O3 (b), RGO/SPCE (c), and Bi2O3@RGO/SPCE in phosphate buffer (pH 7.0) containing 100 µM EP at scan rate of50mVs−1 and (B) corresponding plot of peak currents of EP vs. electrodes. (C) CVs of Bi2O3@RGO/SPCE in phosphate buffer (pH 7.0) containing different con-centrations of EP (a= 25, b=50, c= 75, d=100, e= 125, and f= 150 µM). (D) calibration plot of peak current/µA vs. [EP]/µM. (E) The CVs obtained at Bi2O3@RGO/SPCE in phosphate buffer (pH 7.0) containing 100 µM of EP at various scan rate (50–750 mVs−1). (F) The plot of peak current vs square root of scan rate.

S. Manavalan et al. Ultrasonics - Sonochemistry 51 (2019) 103–110

106

amplitude= 5mV (inset to Fig. 3). The charge transfers resistance (Rct)of Bi2O3/SPCE, RGO/SPCE, and Bi2O3@RGO/SPCE are 96.35Ω,62.43Ω, and 20.56Ω, respectively. The Rct value which response toBi2O3@RGO is 4.6, and 3.0 times smaller than the Bi2O3/SPCE, andRGO/SPCE respectively, which indicates the modification of Bi2O3@RGO on electrode surface drastically decreases the electrode-electrolyteinterfacial resistance.

3.3. Electrocatalysis of EP at Bi2O3@RGO nanocomposite

Under optimum condition, cyclic voltammetry (CV) was initiallyperformed to conform the electrocatalytic sensing performance of

electrodes in the presence of EP. The depict of Fig. 4A shows the CVs ofunmodified SPCE (a), Bi2O3/SPCE (b), RGO/SPCE (c) and Bi2O3@RGO/SPCE (d) toward 100 µM EP in phosphate buffer (pH=7.0). An inferiorredox peak was observed at the higher potential of 0.003–0.372 V atunmodified SPCE, indicates the electrode is incapability to catalyze theredox reaction of EP. The voltammograms of Bi2O3/SPCE, RGO/SPCE,and Bi2O3@RGO/SPCE are exhibited sharp redox peaks at the potentialrange of 0.019–0.418 V. Among them, the Bi2O3@RGO/SPCE showedsuperior catalytic ability at lower potential with high intensity towardEP. The electrocatalytic redox of epinephrine to epinephrine-quinoneinvolved with 2e− and 2H+ process (see Scheme S1 in Supplementaryfile). The peak current at Bi2O3@RGO/SPCE was 9.1, 4.4, and 2.6 foldslarger than that at unmodified SPCE, Bi2O3/SPCE and RGO/SPCE,(inset to Fig. 4A). Thus, the current signal was synergically amplified atthe Bi2O3@RGO modified electrode. The excellent synergic effect be-tween RGO and Bi2O3 is one of the major factors behind the improvedcatalysis.

Fig. 4B shows the CVs of Bi2O3@RGO modified electrode towardsdifferent concentrations of EP. As the concentration of EP increases, thepeak current is also increases linearly from 25 to 150 µM, indicates theabsence of electrode fouling. The plot between peak current and cor-responding concentration exhibits good linearity, thus the nano-composite-modified electrode holds superior electrocatalytic sensingability to EP (Fig. 4C). The effect of scan rate on the electrocatalyticredox of EP at the Bi2O3@RGO/SPCE. As the scan rate increases, thepeak current is also increases linearly from 50 to 750 mVs−1. Fig. 4Dpresents in the clear way of plot between square root of scan rate andresponse current exhibited good linearity, indicates diffusion-controlledelectrocatalytic process of EP at nanocomposite modified electrode.

Fig. 5. (A) Amperometric response of Bi2O3@RGO modified rotating electrode to various concentrations of EP. Here, the supporting electrolyte was phosphate buffer(pH 7.0), the electrode rotation speed was 1000 rpm, and applied electrode potential was 0.18 V. (B) Amperometric response current/µA vs. [EP]/µM. (C)Amperometric response of Bi2O3@RGO modified rotating electrode toward successive injections of 25 µM EP, 0.5 mM of other compounds (glucose, 5-HT, DA, UA,AA, FA, and KCl) and again 25 µM EP (D) Histogram of the selectivity to various interfering substances.

Table 1Comparison of performance of Bi2O3@RGO modified electrode toward EP withpreviously reported works.

Electrode LOD (nM) Linear range (µM) Reference

Au/MWCNT/PANI/TiO2 160 4.9–76.9 [43]Carbon dots 6.1 0.5–200 [44]Au-Ag 505 25–700 [45]CNT 242 25–600 [46]AgNPs-PCA-Au 0.5 0.1–100 [47]β-NiS@RGO/AuNS 540 2–1000 [48]MWCNT/SDS 45 0.1–100 [8]CeO2 nanoparticles 900 2–160 [49]SWCNT 2.3 10–100 [50]Bi2O3@RGO 2.14 0.01–550.25 This work

MWCNT-multi walled carbon nanotube; PANI- Polyaniline; PCA-penicillamine;SWCNT-single walled carbon nanotube; SDS-sodium dodecyl sulfate.

S. Manavalan et al. Ultrasonics - Sonochemistry 51 (2019) 103–110

107

3.4. Amperometric determination of EP

Fig. 5A presents the amperometric (i-t) response obtained at Bi2O3@RGO modified electrode (area=0.018 cm2) toward difference

concentrations of EP. The electrode potential was fixed at 0.18 V. Foreach injection of EP, a sharp and well-defined amperometric responsewas obtained. The steady state current was reached in less than 4 s,representing fast response time. The linear regression plot betweenamperometric current and concentration of EP has showed good line-arity with linear regression of y=0.0982x+0.3479 (Fig. 5B). Thelinear range was 0.01–550.25 µM and the sensitivitiy was5.4555 µA.µM−1.cm−2. The limit of detection (LOD) was calculated tobe 2.14 nM (S/N=3). The LOD was calculated using the equation,LOD=3σ/S, where σ is the standard deviation of intercept of regres-sion line, and S is the slope of the calibration curve. The linear rangecovers the physiological levels of EP. The analytical parameters such as,linear range and LOD are compared in Table 1. Compared to previousmethod, our modified electrode showed either comparable or superiorsensing performance with additional advantages of low-cost, and ro-bust. The electrode able to detect concentration as low as 2.14 nM ofEP, suggesting high sensitivity of the method.

Selectivity of the electrode to detect EP in presence of potentialpossible interferents such as, glucose, serotonin (5-HT), dopamine (DA),uric acid (UA), ascorbic acid (AA), folic acid (FA), and KCl has beenstudied via amperometry. Fig. 5C displays the amperometric responseof Bi2O3@RGO modified electrode toward 25 μM of EP and 0.5 mM ofaforementioned interfering species. As shown in Fig. 5C, the electrodequickly responded to the low concentration amounts of EP, while veryquiet response was shown to other species even at 20-fold higher con-centrations, refers that the electrode is suitable for the selective de-termination of EP. The corresponding histogram is also reflect the sameobservation in a more clear way (Fig. 5D). In additionally, Selectivity ofthe sensor was analyzed with DA and EP in CV method. Fig. S6 displaysthe CV response of Bi2O3@RGO modified electrode toward 50 μM of EPand 0.2mM of DA. According to the results, DA peak response at 0.12 Vand EP peak response at 0.18 V. So, DA peak is not affect the EP peakresponse in CV analysis. In order to the selectivity studies, Bi2O3@RGOmodified electrode is more selective towards EP.

3.5. Stability, repeatability and reproducibility

The amperometric stability of Bi2O3@RGO modified electrode dis-played a stable steady state current response for 2450 s after the suc-cessive injection of 100 µM EP in phosphate buffer (pH 7.0) (see Fig. S5in Supplementary file). The result revealed that 91.35% of initial sensorresponse current was still retained after 2450 s, which reports theBi2O3@RGO towards EP has the excellent operational stability. Thestorage stability of Bi2O3@RGO modified electrode was determined bymonitoring its response to EP every day for 10 days. Every time afterthe use, the electrode was stored in phosphate buffer (pH 7.0) at 5 °C.The modified electrode showed well-defined catalytic responses duringits continuous use. About 94.68% of initial response current was re-tained after its continuous use of 10 days, reveals good storage stability(Fig. 6A). The repeatability and reproducibility were assessed inphosphate buffer (pH 7.0) containing 100 µM EP. The modified elec-trodes exhibits sustainable repeatability with relative standard devia-tion (RSD) of 3.32% for 10 repetitive measurements carried out usingsingle electrode (Fig. 6B). In addition, it exhibits good reproducibility of3.43% for 10 independent measurements (Fig. 6C).

3.6. Real sample analysis

In order to evaluate the practical ability of the modified electrode todetermine EP in human and rat blood serum (Figs. S7 and S8). Theacquired samples were diluted in phosphate buffer (pH 7.0) in 1:4 ratio(5 mL). Initially, the prepared solution of human and rat blood serumsamples were analyzed, then known amounts (mg) of EP was added toprepare stock solution (see Scheme S2 in Supplementary file). Usingstandard addition method, the aliquots of stock solution were injectedto an electrochemical cell and the electrode delivered prompt and

Fig. 6. (A) Electrode stablity test over 10 days. (B) Repeatability test: Responcesof 10 repeated amperometric measurments using same Bi2O3@RGO/SPCE to-ward 100 µM EP. (C) Reproducibility test: Responses of 10 different at Bi2O3@RGO/SPCE.

Table 2Determination of spiked EP in human and rat blood serum samples usingBi2O3@RGO modified electrode.

Biological Samples Spiked (µM) AMP (µM) HPLC (µM) Recovery (%)

Human blood serum 2 1.91 1.98 96.465 4.89 4.95 98.7810 9.78 9.89 98.88

Rat blood serum 2 1.89 1.95 96.925 4.87 4.96 98.1810 9.86 9.93 99.29

AMP- amperometric, HPLC- high performance liquid chromatography,Recovery= amperometric detection/HPLC detection× 100.

S. Manavalan et al. Ultrasonics - Sonochemistry 51 (2019) 103–110

108

stable sensor responses toward each addition of real sample. Theamount of EP spiked, found and recovery were calculated and given inTable 2. They are in the agreeable analytical range, indicating thesuitably of the method in analyzing EP in human and rat blood serum.In additionally, HPLC in parallel was used to validate our findings andthe obtained results were discussed in the Table 2. As can be seen, ourfound recovery results of Bi2O3@RGO modified electrode is in com-parable or agreement with that of HPLC method.

4. Conclusions

A facile and highly sensitive electrochemical sensor was demon-strated for the detection of epinephrine based on Bi2O3@RGO nano-composite. The Bi2O3@RGO nanocomposite was successfully preparedvia a simple, inexpensive and ecofriendly ultrasonic method and itsformation was investigated by XRD, XPS, FE-SEM, and HR-TEM ana-lyze. The large surface area, good electrochemical stability and lowelectrode/electrolyte resistance were observed by voltammetry andimpedance studies. The Bi2O3@RGO modified electrode exhibited ex-cellent catalytic activity and a sensitive EP amperometric sensor wasestablished which displayed sensitivity of 5.4555 µAµM−1 cm−2 and awide linear range of 0.01–550.25 µM; the analytical results are superiorto the existing modified electrodes. The method holds promisingpractical feasibility in human and rat blood serum sample, indicating itspotential in real-time application.

Acknowledgements

The authors extend their appreciation to the Deanship of ScientificResearch at King Saud University for funding this work through re-search group no (RG-1439-84). This work was supported by theMinistry of Science and Technology, Taiwan (MOST 107-2113-M-027-005-MY3).

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.ultsonch.2018.10.008.

References

[1] P.S. Dorraji, F. Jalali, Novel sensitive electrochemical sensor for simultaneous de-termination of epinephrine and uric acid by using a nanocomposite ofMWCNTs–chitosan and gold nanoparticles attached to thioglycolic acid, Sens.Actuat. B: Chem. 200 (2014) 251–258.

[2] B.N. Chandrashekar, B.E.K. Swamy, N.B. Ashoka, M. Pandurangachar,Simultaneous electrochemical determination of epinephrine and uric acid at 1-butyl-4-methyl-pyridinium tetrafluroborate ionic liquid modified carbon pasteelectrode: a voltammetric study, J. Mole. Liquids 165 (2012) 168–172.

[3] S.-F. Wang, D. Du, Q.-C. Zou, Electrochemical behavior of epinephrine at L-cysteineself-assembled monolayers modified gold electrode, Talanta 57 (2002) 687–692.

[4] T. Tavana, M.A. Khalilzadeh, H. Karimi-Maleh, A.A. Ensafi, H. Beitollahi,D. Zareyee, Sensitive voltammetric determination of epinephrine in the presence ofacetaminophen at a novel ionic liquid modified carbon nanotubes paste electrode,J. Mole. Liquids 168 (2012) 69–74.

[5] D.L. Wong, T. Tai, D.C. Wong-Faull, R. Claycomb, R. Kvetňanský, Adrenergic re-sponses to stress, Ann. NY. Acad. Sci. 1148 (2008) 249–256.

[6] N.F. Atta, A. Galal, H. Ekram, A novel sensor of cysteine self-assembled monolayersover gold nanoparticles for the selective determination of epinephrine in presenceof sodium dodecyl sulfate, Analyst 137 (2012) 2658–2668.

[7] A. Sivanesan, S.A. John, Selective electrochemical epinephrine sensor using self‐-assembled monomolecular film of 1, 8, 15, 22‐Tetraaminophthalocyanatonickel (II)on Gold Electrode, Electroanal.: Int. J. Devoted Fund. Pract. Aspects Electroanal. 20(2008) 2340–2346.

[8] T. Thomas, R.J. Mascarenhas, O.J. D'Souza, S. Detriche, Z. Mekhalif, P. Martis,Pristine multi-walled carbon nanotubes/SDS modified carbon paste electrode as anamperometric sensor for epinephrine, Talanta 125 (2014) 352–360.

[9] R. Ramya, P. Muthukumaran, J. Wilson, Electron beam-irradiated polypyrrole de-corated with Bovine serum albumin pores: simultaneous determination of epi-nephrine and L-tyrosine, Biosens. Bioelectron. 108 (2018) 53–61.

[10] L.I. Silva, F.D. Ferreira, A.C. Freitas, T.A. Rocha-Santos, A. Duarte, Optical fiberbiosensor coupled to chromatographic separation for screening of dopamine, nor-epinephrine and epinephrine in human urine and plasma, Talanta 80 (2009)

853–857.[11] A. Struthers, J. Reid, R. Whitesmith, J. Rodger, Effect of intravenous adrenaline on

electrocardiogram, blood pressure, and serum potassium, Heart 49 (1983) 90–93.[12] M. Govindasamy, S. Sakthinathan, S.M. Chen, T.W. Chiu, A. Sathiyan, J.P. Merlin,

Reduced graphene oxide supported cobalt bipyridyl complex for sensitive detectionof methyl parathion in fruits and vegetables, Electroanalysis 29 (2017) 1950–1960.

[13] M. Govindasamy, S. Kogularasu, S.-M. Chen, Y.-H. Cheng, M. Akilarasan, V. Mani,Highly sensitive and selective detection of phenolic compound in river and drinkingwater samples using one-pot synthesized 3D–cobalt oxide polyhedrons, J.Electrochem. Soc. 164 (2017) B463–B469.

[14] N. Jeromiyas, E. Elaiyappillai, A.S. Kumar, S.-T. Huang, V. Mani, Bismuth nano-particles decorated graphenated carbon nanotubes modified screen-printed elec-trode for mercury detection, J. Taiwan Inst. Chem. Eng. (2018), https://doi.org/10.1016/j.jtice.2018.08.030.

[15] U. Rajaji, R. Arumugam, S.-M. Chen, T.-W. Chen, T.-W. Tseng, S. Chinnapaiyan, S.-Y. Lee, W.-H. Chang, Graphene nanoribbons in electrochemical sensors and bio-sensors: a review, Int. J. Electrochem. Sci 13 (2018) 6643–6654.

[16] M. Govindasamy, S.-M. Chen, V. Mani, A. Sathiyan, J.P. Merlin, F.M. Al-Hemaid,M.A. Ali, Simultaneous determination of dopamine and uric acid in the presence ofhigh ascorbic acid concentration using cetyltrimethylammonium bromide–polya-niline/activated charcoal composite, RSC Adv. 6 (2016) 100605–100613.

[17] M. Govindasamy, V. Mani, S.-M. Chen, A. Sathiyan, J.P. Merlin, G. Boopathy,Polyaniline/nickel composite film modified electrode for sensitive electrochemicaldetermination of ascorbic acid, Int. J. Electrochem. Sci. 11 (2016) e10814.

[18] M. Park, J.H. Seo, J.H. Kim, G. Park, J.Y. Park, W.S. Seo, H. Song, K.M. Nam,Effective formation of WO3 nanoparticle/Bi2S3 nanowire composite for improvedphotoelectrochemical performance, J. Phys. Chem. C 122 (2018) 17676–17685.

[19] A. Salazar-Pérez, M. Camacho-López, R. Morales-Luckie, V. Sánchez-Mendieta,F. Ureña-Núñez, J. Arenas-Alatorre, Structural evolution of Bi2O3 prepared bythermal oxidation of bismuth nano-particles, Superficies y vacío 18 (2005) 4–8.

[20] S. Kumaraguru, G.G. Kumar, S. Shanmugan, S. Mohan, R. Gnanamuthu, Enhancedtexture and microhardness of the nickel surface using Bi2O3 particles via electro-deposition technique for engineering application, J. Alloy. Compd. 753 (2018)740–747.

[21] G. Gnanamoorthy, S. Muthamizh, K. Sureshbabu, S. Munusamy, A. Padmanaban,A. Kaaviya, R. Nagarajan, A. Stephen, V. Narayanan, Photocatalytic properties ofamine functionalized Bi2Sn2O7/rGO nanocomposites, J. Phys. Chem. Solids 118(2018) 21–31.

[22] Q. Zhou, Y. Lin, K. Zhang, M. Li, D. Tang, Reduced graphene oxide/BiFeO3 nano-hybrids-based signal-on photoelectrochemical sensing system for prostate-specificantigen detection coupling with magnetic microfluidic device, Biosens. Bioelectron.101 (2018) 146–152.

[23] G.-H. Hwang, W.-K. Han, J.-S. Park, S.-G. Kang, An electrochemical sensor based onthe reduction of screen-printed bismuth oxide for the determination of trace leadand cadmium, Sens. Actuators, B 135 (2008) 309–316.

[24] N.R. Devi, T.V. Kumar, A.K. Sundramoorthy, Electrochemically exfoliated carbonquantum dots modified electrodes for detection of dopamine neurotransmitter, J.Electrochem. Soc. 165 (2018) G3112–G3119.

[25] O. Sadak, A.K. Sundramoorthy, S. Gunasekaran, Facile and green synthesis of highlyconductive graphene paper, Carbon 138 (2018) 108–117.

[26] S. Manavalan, M. Govindasamy, S.-M. Chen, U. Rajaji, T.-W. Chen, M.A. Ali,F.M. Al-Hemaid, M. Elshikh, M.A. Farah, Reduced graphene oxide supportedraspberry-like SrWO4 for sensitive detection of catechol in green tea and drinkingwater samples, J. Taiwan Inst. Chem. Eng. 89 (2018) 215–223.

[27] A.K. Sundramoorthy, S. Gunasekaran, Applications of graphene in quality assuranceand safety of food, TrAC, Trends Anal. Chem. 60 (2014) 36–53.

[28] M. Govindasamy, S. Manavalan, S.-M. Chen, R. Umamaheswari, T.-W. Chen,V. Mani, Determination of oxidative stress biomarker 3-nitro-L-tyrosine usingCdWO4 nanodots decorated reduced graphene oxide, Sens. Actuators, B 272 (2018)274–281.

[29] M. Govindasamy, S.-M. Chen, V. Mani, R. Devasenathipathy, R. Umamaheswari,K.J. Santhanaraj, A. Sathiyan, Molybdenum disulfide nanosheets coated multi-walled carbon nanotubes composite for highly sensitive determination of chlor-amphenicol in food samples milk, honey and powdered milk, J. Colloid InterfaceSci. 485 (2017) 129–136.

[30] M. Govindasamy, V. Mani, S.-M. Chen, T.-W. Chen, A.K. Sundramoorthy, Methylparathion detection in vegetables and fruits using silver@graphene nanoribbonsnanocomposite modified screen printed electrode, Sci. Rep. 7 (2017) 46471.

[31] M. Govindasamy, S.-M. Chen, V. Mani, M. Akilarasan, S. Kogularasu, B. Subramani,Nanocomposites composed of layered molybdenum disulfide and graphene forhighly sensitive amperometric determination of methyl parathion, Microchim. Acta184 (2017) 725–733.

[32] A. Ali, M.R.U.D. Biswas, W.-C. Oh, Novel and simple process for the photocatalyticreduction of CO2 with ternary Bi2O3–graphene–ZnO nanocomposite, J. Mater. Sci.:Mater. Electron. 29 (2018) 10222–10233.

[33] L. Ge, H. Li, X. Du, M. Zhu, W. Chen, T. Shi, N. Hao, Q. Liu, K. Wang, Facile one-potsynthesis of visible light-responsive BiPO4/nitrogen doped graphene hydrogel forfabricating label-free photoelectrochemical tetracycline aptasensor, Biosens.Bioelectron. 111 (2018) 131–137.

[34] A. Verma, R. Jain, Ultrasensitive voltammetric quantification of antioxidant cap-saicin at platform polypyrrole/Bi2O3/graphene oxide in surfactant stabilized media,J. Electrochem. Soc. 164 (2017) H908–H917.

[35] S. Kogularasu, M. Govindasamy, S.-M. Chen, M. Akilarasan, V. Mani, 3D grapheneoxide-cobalt oxide polyhedrons for highly sensitive non-enzymatic electrochemicaldetermination of hydrogen peroxide, Sens. Actuators, B 253 (2017) 773–783.

[36] V. Mani, M. Govindasamy, S.-M. Chen, B. Subramani, A. Sathiyan, J.P. Merlin,

S. Manavalan et al. Ultrasonics - Sonochemistry 51 (2019) 103–110

109

Determination of folic acid using graphene/molybdenum disulfide nanosheets/goldnanoparticles ternary composite, Int. J. Electrochem. Sci 12 (2017) 258–267.

[37] V. Mani, R. Umamaheswari, S.-M. Chen, M. Govindasamy, C. Su, A. Sathiyan,J.P. Merlin, M. Keerthi, Highly sensitive determination of folic acid using grapheneoxide nanoribbon film modified screen printed carbon electrode, Int. J.Electrochem. Sci 12 (2017) 475–484.

[38] S.-M. Chen, R. Umamaheswari, G. Mani, T.-W. Chen, M.A. Ali, A.-H. Fahad,M. Elshikh, M.A. Farah, Hierarchically structured CuFe2O4 ND@RGO composite forthe detection of oxidative stress biomarker in biological fluids, Inorg. Chem. Front.5 (2018) 944–950.

[39] M. Govindasamy, V. Mani, S.-M. Chen, T. Maiyalagan, S. Selvaraj, T.-W. Chen, S.-Y. Lee, W.-H. Chang, Highly sensitive determination of non-steroidal anti-in-flammatory drug nimesulide using electrochemically reduced graphene oxide na-noribbons, RSC Adv. 7 (2017) 33043–33051.

[40] U. Rajaji, M. Govindasamy, S.-M. Chen, T.-W. Chen, X. Liu, S. Chinnapaiyan,Microwave-assisted synthesis of Bi2WO6 flowers decorated graphene nanoribboncomposite for electrocatalytic sensing of hazardous dihydroxybenzene isomers,Compos. B Eng. 152 (2018) 220–230.

[41] J. Chen, B. Yao, C. Li, G. Shi, An improved Hummers method for eco-friendlysynthesis of graphene oxide, Carbon 64 (2013) 225–229.

[42] W. Fang, N. Zhang, L. Fan, K. Sun, The facile preparation of a carbon coated Bi2O3

nanoparticle/nitrogen-doped reduced graphene oxide hybrid as a high-performanceanode material for lithium-ion batteries, RSC Adv. 6 (2016) 99825–99832.

[43] T.P. Tsele, A.S. Adekunle, O.E. Fayemi, E.E. Ebenso, Electrochemical detection ofEpinephrine using Polyaniline nanocomposite films doped with TiO2 and RuO2

Nanoparticles on Multi-walled Carbon Nanotube, Electrochim. Acta 243 (2017)331–348.

[44] T.C. Canevari, M. Nakamura, F.H. Cincotto, F.M. de Melo, H.E. Toma, High per-formance electrochemical sensors for dopamine and epinephrine using nanocrys-talline carbon quantum dots obtained under controlled chronoamperometric con-ditions, Electrochim. Acta 209 (2016) 464–470.

[45] E. Wierzbicka, G.D. Sulka, Nanoporous spongelike Au–Ag films for electrochemicalepinephrine sensing, J. Electroanal. Chem. 762 (2016) 43–50.

[46] E. Wierzbicka, G.D. Sulka, Fabrication of highly ordered nanoporous thin Au filmsand their application for electrochemical determination of epinephrine, Sens.Actuators, B 222 (2016) 270–279.

[47] K. Barman, S. Jasimuddin, Simultaneous electrochemical detection of dopamineand epinephrine in the presence of ascorbic acid and uric acid using aAgNPs–penicillamine–Au electrode, RSC Adv. 6 (2016) 99983–99988.

[48] P. Muthukumaran, C. Sumathi, J. Wilson, G. Ravi, Enzymeless biosensor based on β-NiS@ rGO/Au nanocomposites for simultaneous detection of ascorbic acid, epi-nephrine and uric acid, RSC Adv. 6 (2016) 96467–96478.

[49] A.S. Razavian, S.M. Ghoreishi, A.S. Esmaeily, M. Behpour, L.M. Monzon,J.M.D. Coey, Simultaneous sensing of L-tyrosine and epinephrine using a glassycarbon electrode modified with nafion and CeO2 nanoparticles, Microchim. Acta181 (2014) 1947–1955.

[50] E. Akyilmaz, E. Canbay, E. Dinçkaya, C. Güvenç, İ. Yaşa, E. Bayram, Simultaneousdetermination of epinephrine and dopamine by using candida tropicalis yeast cellsimmobilized in a carbon paste electrode modified with single wall carbon nanotube,Electroanalysis 29 (2017) 1976–1984.

S. Manavalan et al. Ultrasonics - Sonochemistry 51 (2019) 103–110

110