Cyclic voltammetry study of the electrochemical behavior of vanadyl sulfate in absence and presence of antibiotic

Accepted Manuscript Cyclic voltammetry study of the electrochemical behavior of vanadyl sulfate in absence and presence of antibiotic Esam A. Gomaa, Amr Negm, Reham M. Abu-Qarn PII: DOI: Reference:

S0263-2241(18)30437-8 https://doi.org/10.1016/j.measurement.2018.05.046 MEASUR 5547

To appear in:

Measurement

Received Date: Revised Date: Accepted Date:

22 August 2017 12 April 2018 10 May 2018

Please cite this article as: E.A. Gomaa, A. Negm, R.M. Abu-Qarn, Cyclic voltammetry study of the electrochemical behavior of vanadyl sulfate in absence and presence of antibiotic, Measurement (2018), doi: https://doi.org/10.1016/ j.measurement.2018.05.046

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Cyclic voltammetry study of the electrochemical behavior of vanadyl sulfate in absence and presence of antibiotic Esam A. Gomaa, Amr Negm, and Reham M. Abu-Qarn* Chemistry Department, Faculty of Science, Mansoura University, 35516-Mansoura, Egypt *Corresponding author.

 Reham M. Abu-Qarn e-mail: [email protected] Tel: +201007855184.

Abstract The cyclic voltammetry technique was used to study the electrochemical behavior of vanadyl sulfate in absence and presence of antibiotic (cefazolin) in 0.1M KCl under different pH values at 300.15 K. The redox behavior of vanadyl sulfate has been studied by using glassy carbon electrode, Ag/AgCl as a reference electrode and Pt wire as a counter electrode under potential from +1500 mV to -1000 mV. One anodic peak and one cathodic peak are observed in cyclic voltammograms. Peak current ratio and peak potential separation (ΔE) was calculated, the higher values of them gave an indication about systems under study are quasi-reversible. The effect of pH, scan rate and concentration of electroactive species on the interaction between vanadyl sulfate and antibiotic were studied. Charge transfer coefficients (α), the heterogeneous electron transfer rate constants (ks) and the diffusion coefficients (D) involved in the redox reaction were evaluated.

Keywords: Cyclic voltammetry. Vanadyl sulfate. Quasi-reversible. Heterogeneous electron transfer rate constant. Diffusion coefficient. Cefazolin

1. Introduction Cyclic voltammetry is one of the most popular electrochemical technique, which gives qualitative information about an electrochemical process. It is carried out by measuring the resulting current as a function of the applied potential. It is called cyclic due to the current is measured as a response of the applied potential, starting at the initial potential (Ei) and the potential value varying in a linear manner up to the end value (E f). At the end value of the potential, the direction of the potential scan is reversed and the scan takes place in the opposite direction at the same potential range. This technique is accomplished with a three-electrode arrangement. the potential is applied to the working electrode with respect to a reference electrode while an auxiliary (or counter) electrode is used to complete the electrical circuit by conducting electricity from the signal source to the others electrodes in solution. Cyclic voltammetry used in determination mechanism of reactions, a number of electrons transferred through oxidation or reduction process, formal potential, the stoichiometry of a system, heterogeneous rate constants and diffusion coefficient of electroactive species. Cyclic voltammetry is simple, rapid and high sensitive technique, so it used to study the compound such as vanadium with

antibiotics as cefazolin (CFZ). Study of vanadium compounds has received increasing attention in the last years as vanadium plays a significant role in several biochemical processes and used in different fields as industry and medicinal chemistry [1-6]. Vanadyl sulfate is one of many inorganic vanadium compounds, which used in industry in the manufacturing of vanadium battery and used in biochemistry field due to its high physiological importance as it has antitumor or carcinogenic properties. Studying of the electrochemical behavior of vanadyl sulfate is very important to get data, which can be used in many fields [7-9]. Cefazolin sodium (CFZ) is classified as a first generation, semi-synthetic cephalosporin antibiotic having a broad spectrum of activity in vitro against many Gram-positive aerobic cocci but has a limited activity against Gramnegative bacteria [10]. There are many authors published articles, which were explained the using of cyclic voltammetric technique to determine metals, organic and inorganic compounds and the effect of interaction between metals and inorganic compounds [11– 14]. The present study shows the effect of concentration change, pH values change and effect of scan rate on the electrochemical behavior of vanadyl sulfate in absence and presence of cefazolin (CFZ) in 0.1M KCl as supporting electrolyte at 300.15 K by using cyclic voltammetry technique. Also, charge transfer coefficients (α), the heterogeneous electron transfer rate constants (ks) and the diffusion coefficients (D) involved in the redox reaction were evaluated. 2. Experimental 2.1. Chemicals Water was used in the preparation of solutions is bidistilled with a specific conductivity of 0.07 μS cm−1 at 298.15 K. Vanadyl sulfate trihydrate (VOSO4.3H2O, ≥ 99.9%) and (KCl, ≥ 99%) were supplied from Sigma-Aldrich. Vanadyl sulfate trihydrate was used as such without further purification, but Potassium chloride was dried in an oven for 5 h before use at 378.15 K. cefazolin sodium was purchased from Pharco B International. Sodium acetate, acetic acid was purchased from Oxford Co., India, and 99.99% nitrogen was supported byTalkha Co. 2.2. Solutions The stock solutions of 0.1 mol.L -1 of KCl, 0.01 mol.L-1 of VOSO4 were prepared. All chemicals used were prepared in bidistilled water. The pH of the measured solutions was maintained with the addition of diluted acetate buffer and HCl or add potassium dihydrogen phosphate to adjust pH of solution in electrochemical cell at (4.3, 6.3, and 8), respectively. 2.3. Cyclic voltammetry measurement Cyclic voltammetry was carried out by using DY2000, DY2000EN multichannel Potentiostat connected with the electrochemical cell with volumetric capacity of 50 ml as represented in Fig. 1, pH meter MV 87 (Praecitronic, Germany) using a glass electrode (Schott, Germany) with deviation (±0.03), and the solutions was stirred by a magnetic stirrer (magnetic bar coated with Teflon tape). The electrochemical cell consists of three electrodes Pt wire (0.5 mm diameter) as a counter electrode, Ag/AgCl (saturated 0.1M KCl) as a standard electrode and glassy carbon electrode (GCE) as a working electrode with diameter surface area (A= 0.503 cm2). By putting the electrochemical cell in a double jacket and circulation of thermostated water by using ultra-thermostat of the type Kottermann 4130, the temperature of solutions inside the electrochemical cell is kept

constant throughout the experiment at the desired value (±0.005 C). The working electrode was polished to a mirror-like surface after each run using Al2O3 powder (particle size 1-0.03μm). After polishing the electrodes were rinsed with bidistilled water. The electrodes were placed in solutions consisting of the vanadyl sulfate VOSO 4 concentration of stock (0.01M) in potassium chloride (KCl 0.1M). Deoxygenating of solutions were occurred by passing high purity nitrogen for 10 min before each run. The data and graphs plot were analyzed by using Origin lab software.

Fig. 1 The electrochemical setup 3. Results and discussion 3.1. The electrochemical behavior of vanadyl sulfate in 0.1 M KCl The electrochemical behavior of vanadyl sulfate solution in 0.1M KCl at a temperature (300.15 K) in absence of cefazolin has been studied at 1500 to -1000 mV potential window. Cyclic voltammograms in Fig. 2 shows one cathodic peak at 0.041 V and one anodic peak at 0.489 V for vanadyl sulfate solution (2mM), and this may be due to the charge transfer as the predicted mechanism obtained by Plotting Pourbaiux diagram. By plotting potential (E0) versus pH will give a Pourbaix diagram as represented in Fig. 3. The slope obtained from Pourbaix diagram is equal to at 300.15 K. where (h) is the number of protons transferred and (n) is the number of electrons transferred. The obtained slope from Pourbaiux diagram equal to (0.069), which indicated the presence of two electrons transferred and three protons [15, 16].

0.0003 0.0002

Current (A)

0.0001 0.0000 -0.0001

a

-0.0002

b

-0.0003 -0.0004 1.0

0.5

0.0

-0.5

-1.0

Potential(E/V. vs.Ag/AgCl)

Fig. 2 Cyclic voltammograms of (a) 0.1 M KCl and (b) 2mM VOSO 4 in 0.1 M KCl at 0.1 V.s-1

0.50

0.45

0.40

E, V

0.35

0.30

0.25

0.20

0.15 4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

pH

Fig. 2 Pourbaiux diagram of 2 mM vanadyl sulfate in0.1 M KCl. Cathodic mechanism: H3V2O7- + 3H+ + 2eV2O4 + 3H2O (1) Anodic mechanism: V2O4 + 3H2O H3V2O7- + 3H+ + 2e(2) 3.2. Influence of concentration change By adding different concentrations from vanadyl sulfate (0.00033, 0.001, 0.0013 and 0.002 M) in 0.1 M KCl at scan rate (0.1 V.s-1) as shown in cyclic voltammograms in Fig. 4 that show increased in anodic, cathodic peak height and also show shifted slightly in potential to more positive by increasing vanadyl sulfate concentration and this can be explained by presence a large number of electroactive species in solution [7, 8]. We

obtain a linear range between concentrations and current as in Fig. 5 with a very good linear correlation r2 = 0.93. Increasing in anodic peak current by increasing the concentration of vanadyl sulfate can give an indication of the system may be diffusion controlled [9, 10].

0.0003

0.0002

Current (A)

0.0001

0.0000

-0.0001

a

-0.0002

f

d e

cb

-0.0003

-0.0004 1.0

0.5

0.0

-0.5

-1.0

Potential(E/V. vs.Ag/AgCl

Fig. 4 Cyclic voltammograms of different concentrations of VOSO 4 in 0.1M KCl (a) 0.00033, (b) 0.00067, (C) 0.001, (d) 0.0013, (e) 0.00167, and (f) 0.002M.

-0.00003

-0.00004

Current (A)

-0.00005

-0.00006

-0.00007

-0.00008

-0.00009 0.0004

0.0008

0.0012

0.0016

0.0020

-1

Concentration (mol.L )

Fig. 5 Anodic peak current versus concentration of vanadyl sulfate in 0.1M KCl

3.3. Influence of scan rate change Different scan rates from 10 to 100 mV.s -1 were applied to study the electrochemical behavior of vanadium ions in solution as represented in Fig. 6. With increasing scan rates, the peak potential for the anodic process increased, but the peak potential for the cathodic process decreased. The linear change in peak current for the anodic and cathodic process versus square root of potential scan rate in Fig. 7 indicates that the processes are surface controlled and the rate determining step is the diffusion of vanadium ions [17-19]. The peak current for cathodic and anodic, the peak potential data, the peak potential separation and peak current ratio at all different scan rates that were applied in the study of the electrochemical behavior for 2 mM of VOSO 4 are tabulated in Table 1. The peak potential separation of the anodic and their corresponding cathodic peak increased in linearity as scan rate increased as obviously observed in Fig. 8 and this is considered as an evidence of the irreversible nature of the electrochemical reactions [20]. The peak current ratio is found to be greater than unity in all applied scan rates and this gives an indication about the system is quasi-reversible but slightly less than unity in (ʋ = 0.10 V.s-1). Table 1 Peak potential, current peak, peak potential separation and peak current ratio at different scan rates for cyclic voltammograms of 2 mM VOSO 4 in 0.1 M KCl. ʋ (V.s-1)

ʋ1/2

Epa (V)

Epc (V)

-ipa (mA)

ipc (mA)

ΔE (V)

ipa/ipc

0.10

0.316

0.489

0.041

0.0833

0.091

0.448

0.915

0.05

0.223

0.488

0.071

0.0679

0.054

0.417

1.26

0.02

0.141

0.487

0.098

0.0387

0.035

0.389

1.09

0.01

0.100

0.487

0.11

0.0294

0.021

0.377

1.413

0.0003

0.0002

Current (A)

0.0001

0.0000

-0.0001

100 mV.S-1 50 mV.S-1 20 mV.S-1 10 mV.S-1

-0.0002

-0.0003 1.0

0.5

0.0

Potential(E/V. vs.Ag/AgCl)

-0.5

-1.0

Fig. 6 Cyclic voltammograms of 2 mM vanadyl sulfate in 0.1M KCl at different scan rates.

0.00010 0.00008

ipc

0.00006

Peak current (A)

0.00004 0.00002 0.00000 -0.00002 -0.00004 -0.00006

ipa

-0.00008 -0.00010 0.10

0.15

0.20

0.25

0.30

0.35

SQRT of scan rate (VS-1)

Fig. 7 Peak current density of the cathodic and anodic process versus SQRT of scan rate for 2 mM VOSO4.

0.45 0.44 0.43

Ep(V)

0.42 0.41 0.40 0.39 0.38 0.37 0.00

0.02

0.04

0.06

0.08

0.10

-1

Scan rate (VS )

Fig. 8 Peak potential separation versus scan rate for cyclic voltammograms of 2 mM VOSO4. 3.4. Influence of changing in pH The effect of changing pH values was studied for 2 mM VOSO 4 in 0.1 M KCl at 100 mV.s-1. Cyclic voltammograms of VOSO4 at different pH values are presented in Fig. 9

0.0003

0.0002

Current (A)

0.0001

0.0000

-0.0001

pH = 4.3 pH = 6.3 pH = 8

-0.0002

-0.0003 1.0

0.5

0.0

-0.5

-1.0

Potential(E/V. vs.Ag/AgCl)

Fig. 9 Cyclic voltammograms of 2 mM VOSO4 at different pH in 0.1M KCl at 100 mV.s1.

-0.000068 -0.000070

Current (A)

-0.000072 -0.000074 -0.000076 -0.000078 -0.000080 -0.000082 -0.000084 4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

pH

Fig. 10 The anodic peak current versus pH changes for 2 mM VOSO4 at 100 mV.s-1. By comparing the peak potential and peak current at different pH values as in Fig. 10, we found the best detection and lower peak potential value was obtained at pH = 4.3. 3.5. The electrochemical behavior of vanadyl sulfate in presence of CFZ in 0.1 M KCl

The electrochemical behavior of vanadium ions in presence of cefazolin in 0.1M KCl at a temperature (300.15 K) have been studied at 1500 to -1000 mV potential window. Cyclic voltammograms in Fig. 11 shows moves in peak potential position for 2 mM of vanadyl sulfate in presence of 3 mM cefazolin for anodic from 0.489 to 0.545 V and slightly moves in cathodic peak potential from 0.041 to 0.0769 V. Also, the intensity of the peak has been changed and these observations confirmed the interaction between vanadium ions and cefazolin. 0.0003

0.0002

Current (A)

0.0001

0.0000

-0.0001

2mM VOSO4

-0.0002

In presence of 6mMCFZ -0.0003 1.0

0.5

0.0

-0.5

-1.0

Potential(E/V. vs.Ag/AgCl

Fig. 11 Cyclic voltammograms of 2 mM VOSO4 and 2 mM VOSO4 in presence of 6 mM CFZ in 0.1M KCl at 100 mV.s-1. 3.6. Influence of scan rate change in presence of CFZ Different scan rates from 10 to 100 mV.s -1 were applied to study the electrochemical behavior of vanadium ions in presence of CFZ as represented in Fig. 12. The electrochemical behavior of vanadium ions in presence of CFZ was found to be the same as in the case of free ions. The peak potential for the anodic process increased as the scan rate increased, but the peak potential for the cathodic process decreased. From the relation between the peak current density of the anodic and cathodic peaks versus SQRT of the scan rates in Fig. 13, we obtain a linear change in the cathodic and anodic peak current that indicates the processes are surface and diffusion controlled. The peak current for cathodic and anodic, the peak potential data, the peak potential separation and peak current ratio at all different scan rates that were applied in the study of the electrochemical behavior for 2 mM of VOSO4 in presence of CFZ are listed in Table 2. The peak potential separation of the anodic and their corresponding cathodic peak increased as scan rate increased as obviously observed in Fig. 14 and this is considered as an evidence of the irreversible nature of the electrochemical reactions and give an indication of the system is quasi-reversible.

0.0003

0.0002

Current (A)

0.0001

0.0000

-0.0001

100 mV.S-1 50 mV.S-1 20 mV.S-1 10 mV.S-1

-0.0002

-0.0003 1.0

0.5

0.0

-0.5

-1.0

Potential(E/V. vs.Ag/AgCl)

Fig. 12 Cyclic voltammograms of 2 mM vanadyl sulfate in presence of 6 mM CFZ in 0.1M KCl at different scan rates. Table 2 Peak potential, current peak, peak potential separation and peak current ratio at different scan rates for cyclic voltammograms of 2 mM VOSO 4 in presence of 6 mM cefazolin in 0.1 M KCl. ʋ (V.s-1)

ʋ1/2

Epa (V)

Epc (V)

-ipa (mA)

ipc (mA)

ΔE (V)

ipa/ipc

0.10

0.316

0.525

0.098

0.093

0.080

0.427

1.2

0.05

0.223

0.477

0.098

0.059

0.044

0.379

1.3

0.02

0.141

0.477

0.146

0.035

0.024

0.331

1.5

0.01

0.100

0.477

0.166

0.023

0.015

0.311

1.5

0.08

ipc

0.06

Peak current (A)

0.04 0.02 0.00 -0.02 -0.04 -0.06

ipa

-0.08 -0.10 0.10

0.15

0.20

0.25

0.30

0.35

-1

SQRT of scan rate (VS )

Fig. 13 Peak current density of the cathodic and anodic process versus SQRT of scan rate for 2 mM VOSO4 in presence of CFZ.

0.44 0.42 0.40

Ep(V)

0.38 0.36 0.34 0.32 0.30 0.00

0.02

0.04

0.06

0.08

0.10

Scan rate (VS-1)

Fig. 14 Peak potential separation versus scan rate for cyclic voltammograms of 2 mM VOSO4 in presence of CFZ. 3.7. Influence of changing in pH in presence of CFZ The effect of changing pH values was studied for 2 mM VOSO 4 in presence of CFZ in 0.1 M KCl by adding acetate buffer and HCl to the solution under study to maintain pH (4.3, 6.3 and 8) at 100 mV.s -1. Cyclic voltammograms of VOSO4 at different pH values are presented in Fig. 15.

0.0003

0.0002

Current (A)

0.0001

0.0000

-0.0001

pH=4.3

-0.0002

pH=6.3 pH=8 -0.0003 1.0

0.5

0.0

-0.5

-1.0

Potential(E/V. vs.Ag/AgCl)

Fig. 15 Cyclic voltammograms of 2 mM VOSO4 in presence of 6 mM CFZ at different pH in 0.1M KCl at 100 mV.S -1.

-0.000055 -0.000060 -0.000065

Current (A)

-0.000070 -0.000075 -0.000080 -0.000085 -0.000090 -0.000095 4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

pH

Fig. 16 The anodic peak current versus pH changes for 2 mM VOSO 4 in presence of 6 mM CFZ at 100 mV.s-1. By comparing the peak potential and peak current at different pH values as in Fig. 16, we found the best detection and lower peak potential value was obtained at pH = 4.3. The electrochemical properties at different pH values are decreased in presence of CFZ than in absence it. This can be attributed to vanadyl sulfate and cefazolin interaction. 3.8. Calculation Charge transfer rate constants (ks) and diffusion coefficient (D)

The diffusion coefficient (D) was calculated from Eq. (3) of the cathodic peak current of a reversible or quasi‐reversible system [21].

ip = (2.69 x 105) n3/2 A C D1/2 ν1/2

(3)

where the surface area of glassy carbon electrode and concentration of the sample are denoted by A (cm2), C (mmol.L-1) respectively. The scan rate that applied in cyclic voltammograms is denoted by ν (V.s-1), D (cm2.s-1) is the denotation for the diffusion coefficient and n is the number of transferred electrons involved in the transfer reaction. By using Klinger and Kochi Eq. (4), the heterogeneous charge transfer rate constant (ks) was determined and its values are tabulated in Table 3 [22]. (4) Where α is the charge transfer coefficient, nα is the number of electrons involved in the rate determining step, F is the Faraday constant, R is the gas constant and equal (8.314 J.mol-1. K-1) and T is the temperature (K). The values of the term αn α can be calculated from Eq. (5) by using Epc/2 as the half peak potential. (5) Table 3 Charge transfer rate constant (ks), diffusion coefficient (D), cathodic peak potential (Epc) and cathodic peak current (ipc) at different scan rates for cyclic voltammograms of 2 mM VOSO4 in presence of 6 mM cefazolin in 0.1 M KCl. ID

ʋ (V.s-1)

Epc (v)

Ipc (mA)

D x 103 (cm2. ks s-1)

VOSO4

0.10

0.041

0.091

4.893

0.9275

0.05

0.071

0.054

2.7583

0.5086

0.02

0.098

0.035

2.4236

0.3112

0.01

0.11

0.021

1.5233

0.1770

VOSO4 in 0.10 presence of CFZ 0.05

0.098

0.080

3.2660

0.7743

0.098

0.044

1.3978

0.5349

0.02

0.146

0.024

0.6863

0.3992

0.01

0.166

0.015

0.4507

0.3332

By comparing the results of the heterogeneous charge transfer rate constant ks for vanadium ions in presence and absence of CFZ, it is observed that free vanadium ions have greater value than that of vanadium ions in presence of CFZ at 300.15 K temperature that predicts the reduction of charge transfer velocity as a result of interaction between vanadyl sulfate and cefazolin [21‐ 25]. 4. Conclusions

The electrochemical behavior of the vanadyl sulfate in absence and presence of cefazolin in 0.1 M KCl at a temperature (300.15 K) have been studied by using cyclic voltammetry technique. The effect of concentration, pH, and different scan rates have been studied. The peak current ratio support that the system is quasi-reversible. This study confirmed the interaction between vanadyl sulfate and cefazolin from the values of the heterogeneous charge transfer rate constant (ks), which the values of (ks) in presence of cefazolin are less than that in the case of the free metal ion. References 1. Wever, R., Kustin, K.: Vanadium: a biologically relevant element. Advances in inorganic chemistry, 35(1990), 81-115. doi.org/10.1016/S0898-8838(08)60161-0‫‏‬ 2. Rehder, D.: Bioanorganische chemie des vanadiums. Angewandte Chemie, 103(2) (1991), 152-172.‫‏‬doi: 10.1002/ange.19911030206 3. Butler, A., Carrano, C. J.: Coordination chemistry of vanadium in biological systems. Coordination chemistry reviews, 109(1) (1991), 61-105.‫‏‬ doi.org/10.1016/0010-8545(91)80002-U 4. Hoppe, E., Limberg, C.: Oxo vanadium (V) tetrathiacalix [4] arene complexes and their activity as oxidation catalysts. Chem. Eur. 13(2007) 7006. doi: 10.1002/chem.200700354 5. Xie, M., Gao, L., Li, L., Liu, W., Yan, S.: A new orally active antidiabetic vanadyl complex–bis (α-furancarboxylato) Oxo vanadium (IV). J. Inorg. Biochem. 99 (2005) 546-551. doi:10.1016/j.jinorgbio.2004.10.033 6. Sheela, A., Vijayaraghavan, R.: Synthesis, spectral characterization, and antidiabetic study of new furan-based vanadium (IV) complexes. J. Coord. Chem. 64 (2011) 511. doi: 10.1080/00958972.2010.550916 7. Gomaa, E. A., Abu-Qarn, R. M.: Ionic association and thermodynamic parameters for solvation of vanadyl sulfate in ethanol-water mixtures at different temperatures. Journal of Molecular Liquids, 232 (2017), 319-324.‫‏‬ doi.org/10.1016/j.molliq.2017.02.085 8. Bo, T., Chuan-wei, Y., Qing, Q., Hua, L., Fu-hui, W.: Battery Bimonthly 4 (2003)023. 9. Shunquan, Z., Weirong, S., Qian, W., Haitao, Y., Baoguo, W.: Review of R&D status of vanadium redox battery. Chemical industry and engineering progress. 26 (2007)207. 10. El-Desoky, H. S., Ghoneim, E. M., Ghoneim, M. M.: Voltammetric behavior and assay of the antibiotic drug cefazolin sodium in bulk form and pharmaceutical formulation at a mercury electrode. Journal of pharmaceutical and biomedical analysis, 39(5) (2005), 1051-1056. doi.org/10.1016/j.jpba.2005.05.020 11. ‫‏‬Rahman, F., Habiballah, I. O., Skyllas-Kazacos, M.: Electrochemical behavior of vanadium electrolyte for vanadium redox battery-a new technology for large scale energy storage systems. Proc. of the Cigre, (2004), 1-8.‫‏‬ 12. Friedrich, A., Hefele, H., Mickler, W., Mönner, A., Uhlemann, E., Scholz, F.: Voltammetric and potentiometric studies on the stability of vanadium (IV) complexes. A comparison of solution phase voltammetry with the voltammetry of microcrystalline solid compounds. Electroanalysis, 10(4) (1998), 244-248.‫‏‬ doi: 10.1002/(SICI)1521-4109(199804)10:4<244::AID-ELAN244>3.0.CO;2-W

13. Li, S., Huang, K., Liu, S., Fang, D., Wu, X., Lu, D., Wu, T.: Effect of organic additives on positive electrolyte for vanadium redox battery. Electrochimica Acta, 56(16) (2011), 5483-5487.‫‏‬doi.org/10.1016/j.electacta.2011.03.048 14. Wu, X., Wang, J., Liu, S., Wu, X., Li, S.: Study of vanadium (IV) species and corresponding electrochemical performance in concentrated sulfuric acid media. Electrochimica Acta, 56(27) (2011), 10197-10203.‫‏‬ doi.org/10.1016/j.electacta.2011.09.006 15. Verink, E. D.: Simplified procedure for constructing Pourbaix diagrams. Uhlig's Corrosion Handbook, Third Edition (2011): 93-101.‫‏‬ 16. Baker, J. E.: An Electrochemical Characterization of a Vanadium-based Deoxydehydration Catalyst. (Doctoral dissertation, University of Arkansas), (2017).‫‏‬ 17. Yuan, W., Yan, J., Tang, Z., Ma, L.: Synthesis of high performance Li3V2 (PO4) 3/C cathode material by ultrasonic-assisted sol–gel method. Ionics, 18(3) (2012), 329-335.‫‏‬doi:10.1007/s11581-011-0652-1 18. Sun, C., Rajasekhara, S., Dong, Y., Goodenough, J. B.: Hydrothermal synthesis and electrochemical properties of Li3V2 (PO4) 3/C-based composites for lithiumion batteries. ACS applied materials & interfaces, 3(9) (2011), 3772-3776.‫ ‏‬doi: 10.1021/am200987y 19. Dokko, K., Koizumi, S., Nakano, H., Kanamura, K.: Particle morphology, crystal orientation, and electrochemical reactivity of LiFePO 4 synthesized by the hydrothermal method at 443 K. Journal of Materials Chemistry, 17(45) (2007), 4803-4810.‫‏‬doi: 10.1039/B711521K 20. Yin, S. C., Strobel, P. S., Grondey, H., Nazar, L. F.: Li2. 5V2 (PO4) 3: a roomtemperature analogue to the fast-ion conducting high-temperature γ-phase of Li3V2 (PO4) 3. Chemistry of materials, 16(8) (2004), 1456-1465.‫ ‏‬doi: 10.1021/cm034802f 21. Donald T.S., S. Andrzej, and L.R. Julian.: Electrochemistry for Chemists. 2nd edition. John Wiley & Sons Inc.: New York, NY 1995. 22. Klingler, R. J., Kochi, J. K.: Electron-transfer kinetics from cyclic voltammetry. Quantitative description of electrochemical reversibility. The Journal of Physical Chemistry, 85(12) (1981), 1731-1741.‫‏‬ 23. Brown, E. R., Sandifer, J. R.: Cyclic voltammetry, AC polorography and related techniques. Physical Methods of Chemistry, 2 (1986), 273.‫‏‬ 24. Gupta, R., Gamare, J., Sharma, M. K., Kamat, J. V.: Electrochemical investigations of Pu (IV)/Pu (III) redox reaction using graphene modified glassy carbon electrodes and a comparison to the performance of SWCNTs modified glassy carbon electrodes. Electrochimica Acta, 191 (2016), 530-535. doi.org/10.1016/j.electacta.2016.01.077‫‏‬ 25. Cozar, O., Bratu, I., Szabo, L., Cozar, I. B., Chiş, V., David, L.: IR and ESR study of copper (II) complexes with 15 N-labelled lysine and ornithine. Journal of Molecular Structure, 993(1) (2011), 397-403.‫‏‬ doi.org/10.1016/j.molstruc.2011.02.001

Research highlights for

Cyclic voltammetry study of the electrochemical behavior of vanadyl sulfate in absence and presence of Cefazolin Esam A. Gomaa, Amr Negm, and Reham M. Abu-Qarn* Chemistry Department, Faculty of Science, Mansoura University, 35516-Mansoura, Egypt *Corresponding author.

 Reham M. Abu-Qarn e-mail: [email protected] Tel: +201007855184.

Research highlights    

The electrochemical behavior of vanadyl sulfate was studied. The peak separation and peak current ratio were calculated. The diffusion coefficient were obtained. The effect of concentration, scan rate and pH were discussed.