A disposable electrochemical sensor based on iron molybdate for the analysis of dopamine in biological samples

Article abstract of DOI:10.1039/d1nj01718g

Developing cost-effective approaches for the fabrication of electrochemical devices is instantly needed for transferring from basic research to point-care technology. Herein, we report an electrochemical sensing platform based on an iron molybdate (Fe₂(MoO₄)₃)-modified screen-printed carbon electrode (SPCE) for the sensitive and selective sensing of dopamine (DA). The formation and purity of Fe₂(MoO₄)₃was characterizedviamultiple spectroscopic techniques. Likewise, the electrochemical performance of the Fe₂(MoO₄)₃modified SPCE was probedviacyclic voltammetry and differential pulse voltammetry. Fe₂(MoO₄)₃/SPCE exhibited a 1.44-fold increase in electrochemical sensing activity towards DA than bare SPCE. In a range as wide as from 0.01 to 225 μM, a linear relationship is well established with the value of correlation coefficient being 0.9914. The limit of detection (S/N = 3) is well defined as 0.002 μM, which is lower than that reported previously. The fabricated Fe₂(MoO₄)₃/SPCE shows good anti-interference ability towards DA detection in the presence of numerous co-interfering compounds at a higher level. Moreover, a biological analysis indicated that spiked DA can be determined accurately by Fe₂(MoO₄)₃modified SPCE with the recovery rate in the range of 99.30-99.80% in human serum samples. Based on the above-mentioned results, the proposed electrochemical sensor has great potential in the fields of biological detection.

Full text of DOI:10.1039/d1nj01718g

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A disposable electrochemical sensor based on
iron molybdate for the analysis of dopamine in
biological samples†
Cite this: New J. Chem., 2021,
45, 11644
c
Elumalai Ashok Kumar,ab Tse-Wei Chen,cde Shen-Ming Chen,
*
a
Tzyy-Jiann Wang,
Allen Joseph Anthuvan,f Suliman Yousef AlOmar,g
b
Naushad Ahmadh and Yu-Hsu Chang
Developing cost-effective approaches for the fabrication of electrochemical devices is instantly needed
for transferring from basic research to point-care technology. Herein, we report an electrochemical
sensing platform based on an iron molybdate (Fe2(MoO4)3)-modified screen-printed carbon electrode
(SPCE) for the sensitive and selective sensing of dopamine (DA). The formation and purity of Fe2(MoO4)3
was characterized via multiple spectroscopic techniques. Likewise, the electrochemical performance of
the Fe2(MoO4)3 modified SPCE was probed via cyclic voltammetry and differential pulse voltammetry.
Fe2(MoO4)3/SPCE exhibited a 1.44-fold increase in electrochemical sensing activity towards DA than
bare SPCE. In a range as wide as from 0.01 to 225 mM, a linear relationship is well established with the
value of correlation coefficient being 0.9914. The limit of detection (S/N = 3) is well defined as 0.002 mM,
which is lower than that reported previously. The fabricated Fe2(MoO4)3/SPCE shows good anti-
interference ability towards DA detection in the presence of numerous co-interfering compounds at a
higher level. Moreover, a biological analysis indicated that spiked DA can be determined accurately by
Fe2(MoO4)3 modified SPCE with the recovery rate in the range of 99.30–99.80% in human serum samples.
Based on the above-mentioned results, the proposed electrochemical sensor has great potential in the
fields of biological detection.
Received 8th April 2021,
Accepted 27th May 2021
DOI: 10.1039/d1nj01718g
rsc.li/njc
important catecholamine and neurotransmitter for living
organisms.1,2 It plays an essential role in the cardiovascular,
1. Introduction
Neurotransmitters play a vital role in the human body that central nervous, and endocrine regulation systems.3,4 The
helps in communication between the brain and nerve cells. inadequate level of DA in biological fluids causes diseases such
Among the various neurotransmitters, dopamine (DA) is an as schizophrenia, hyperactivity disorder, Tourette syndrome,
senile dementia, and Huntington’s, Parkinson’s, and Alzheimer’s
diseases.5–7 Besides, some toxic agents in the environment would
a Department of Electro-Optical Engineering, National Taipei University of
damage the human brain, liver, and kidney, which may lead to
inadequate DA level.8–10 Therefore, it is of excessive importance to
Technology, Taipei 106, Taiwan
b Department of Materials and Mineral Resources Engineering, Institute of Mineral
develop accurate, sensitive, and low-cost analytical techniques for
Resources Engineering, National Taipei University of Technology, Taipei 106,
detecting DA in biological samples. At present, numerous
techniques, such as fluorescence, chemiluminescence, colorimetry,
capillary electrophoresis, high-performance liquid chromatography,
electrochemical sensing, and liquid chromatography/tandem mass
spectrometry, are available for the detection of DA.11–20 Among
them, electrochemical sensing gained considerable attention due
to its simplicity, low cost, rapid response, user-friendliness, and
real-time detection.21–24
Transition metal molybdates (TMMs) have been widely used
in electrochemical application due to their efficient catalytic
performance.25–27 Sundaresan et al. reported barium molybdate
as a promising electrocatalyst for the detection of DA.28
Taiwan
c Department of Chemical Engineering and Biotechnology,
National Taipei University of Technology, Taipei 106, Taiwan.
E-mail: smchen78@ms15.hinet.net; Fax: +886 2270 25238; Tel: +886 2270 17147
d Research and Development Center for Smart Textile Technology, National Taipei
University of Technology, Taipei 106, Taiwan
e Department of Materials, Imperial College London, London, SW7 2AZ, UK
f DRDO-Centre for Life Sciences, Bharathiar University, Coimbatore 641 046, India
g Doping Research Chair, Zoology Department, College of Science,
King Saud University, Kingdom of Saudi Arabia
h Chemistry Department, College of Science, King Saud University, Kingdom of
Saudi Arabia
† Electronic supplementary information (ESI) available. See DOI: 10.1039/
d1nj01718g
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Fan et al. developed an electrochemical sensor based on cobalt fabricated Fe2(MoO4)3 sensor provides several significant merits
porphyrin/tantalum molybdate for the simultaneous detection such as (1) superior conductivity, (2) wide linear range because
of DA.29 Nanomaterials owing to their high surface area and of the large surface area, (3) excellent selectivity ability due to
high activity are almost utilized in all sensor applications.30 the specific DA recognition, (4) high accuracy, and (5) good
Zhang et al. reported nickel molybdate nanosheets as a biocompatibility for real-time monitoring of DA.
potential catalytic platform for NADH and ethanol sensing.31
Among these different TMMs, iron molybdate (Fe2(MoO4)3) is
2. Experimental
2.1. Materials
crystallized in a structure of monoclinic with 16-FeO6 octahedra
and 24-MoO4 tetrahedra, which share corners in a unit cell,
which has the advantages of low cost, good conductivity,
Iron acetate (Fe(CO2CH3)2) and sodium molybdate dihydrate
environmental friendliness, high theoretical specific capacity,
(Na2MoO4) were purchased from Sigma Aldrich. Urea
chemical stability and natural abundance, and it is the most
(NH2CONH2) and ethanol were purchased from Fluka chemical
promising electrode material.32,33 However, Fe2(MoO4)3 have
companies. All chemicals were of analytical grade and used
some limitations, such as poor conductivity and electrochemical
without further purification. Phosphate buffer solutions (PBS)
stability, due to structural breakdown during redox reactions
0.05 M were used in all the electrochemical studies. Double
that leads to low electrochemical performance.34 Arumugam
distilled water (DI) was used for all the experiments.
et al. reported nanoplate-like iron molybdate for the selective
determination of promethazine hydrochloride.35 Different
2.2. Instrumentation
methods such as the sol–gel method, co-precipitation method,
The structural morphology, crystalline structure and chemical
impregnation method and hydrothermal method have been
used for the synthesis of Fe2(MoO4)3.36–46 Among the above-
composition of the as-prepared Fe2(MoO4)3 were characterized
via transmission electron microscopy (TEM) (JEOL: JEM-
1200EX), and mapping analysis was performed via FE-SEM
mentioned synthesis techniques, the hydrothermal technique
has been widely used as an electrocatalyst owing to its simple,
(SEM Hitachi S-3000H) and X-ray diffraction (XRD; XPERT-
environmentally, high phase purity, well-defined structural
morphology, low-cost, and highly efficient method.47,48 Several
PRO spectrometer from PANalytical B.V. with Cu Ka radiation
l = 1.5406 Å). The functional groups were identified via FT-IR
(FT-IR-6600 spectrometer). The electrochemical measurements
hydrothermally prepared materials offer low detection limit due
to their precise morphology and functionality.49 To the best of
were conducted at room temperature on an electrochemical
our knowledge, the Fe2(MoO4)3 modified electrode was utilized
workstation (CH Instrument, USA) connected to a computer.
the first time for the electrochemical determination of DA.
A typical three-electrode system consisting of a saturated KCl
In this study, we utilized a Fe2(MoO4)3 modified electrode
silver–silver chloride (sat. KCl Ag/AgCl) as the reference
for the electrochemical detection of DA. The as-prepared
electrode, platinum wire as the counter electrode, and a
Fe2(MoO4)3 was analyzed by different spectroscopic, micro-
scopic, and voltammetric techniques. The electrochemical
performance was scrutinized by cyclic voltammetry (CV) and
SPCE (0.071 cm2) as the working electrode was used. All the
experiment was carried in a nitrogenous atmosphere.
differential pulse voltammetry (DPV) techniques. The effect of
various parameters such as pH, scan rate, different concentration
2.3. Synthesis of Fe2(MoO4)3
and detection limit was evaluated. Significantly, the Fe2(MoO4)3 In this study, Fe2(MoO4)3 were prepared by the simple hydro-
modified electrode exhibits an improved electrocatalytic activity thermal method, as represented in Scheme 1. Briefly, 0.1 M Fe
towards DA via various physicochemical properties. Notably, the (CO2CH3)2 and 0.1 M Na2MoO4 were dissolved in 20 mL DI
Fe2(MoO4)3 modified electrode delivers a low limit of detection, water and stirred until a homogeneous mixture was obtained at
wide linear range and acceptable selectivity. Compared with atmospheric temperature. Then, 5 mg urea was dissolved in
previously reported electrodes for the detection of DA, the 10 mL DI water, and the mixture was added to the above-
Scheme 1 The synthesis procedure of (Fe2MoO4)3 by the hydrothermal method.
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Fig. 1 (A) XRD pattern and (B) Raman spectra of Fe2(MoO4)3.
mentioned solution and stirred for another 30 min. The final 2.4. Fabrication of the DA sensor
solution is transferred to a Teflon-lined stainless steel auto-
clave, shield tightly, maintained at 140 1C for 12 h and left
undisturbed until it reached room temperature. Then, it was
washed with DI water and ethanol several times and dried at
50 1C for 12 h and finally calcined at 600 1C for 4 h. The
obtained Fe2(MoO4)3 were ground and used for further electro-
chemical studies. Scheme 1 shows the schematic representation
of the synthesis methodology of Fe2(MoO4)3.
Initially, the bare SPCE was cleaned with DI water and ethanol
every few seconds to remove unwanted impurities over the
SPCE surface. The SPCE electrode was modified with
Fe2(MoO4)3 for the sensitive electrochemical detection of DA.
For the preparation of an Fe2(MoO4)3 suspension, the as-
synthesized Fe2(MoO4)3 electrocatalyst was ultrasonically
dispersed in DI water to form a 2 mg mLꢀ1. Then, 8 mL of
Fe2(MoO4)3 dispersed in 1 mL DI water was gently drop-coated
Fig. 2 (A–C) TEM image of (D) line EDX spectra and (E–G) mapping image of Fe2(MoO4)3.
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Fig. 3 (A) CV curves of bare SPCE and Fe2(MoO4)3/SPCE in the absence and presence of 150 mM DA in 0.05 M PBS (pH 7.0) at a scan rate of 50 mV sꢀ1
.
(B) CV curves at different DA concentrations at a scan rate of 50 mV sꢀ1. (C) CV curves at different scan rates with a DA concentration of 150 mM.
(D) Corresponding calibration plot of the redox current response and the scan rates.
on the electrode surface and dried to dehydrate the water crystallinity and a more specific area, and the active site will
content at 50 1C for 15 min. Later, the modified SPCE was improve the redox process54 (Fig. 2(A–C)). The corresponding
rinsed to remove the loosely bounded particles with water, and
electrochemical studies were carried out.
elemental mapping of Fe2(MoO4)3 confirms the presence of Fe,
Mo and O elements (Fig. 2(E–G)). The line energy dispersive
spectrum shows that Fe, Mo and O elements are distributed
evenly in Fe2(MoO4)3.
3. Results and discussion
3.2. Electrochemical studies
3.1. Material characterization
The concentration (mg) of Fe2(MoO4)3 for the SPCE preparation
The structural and phase analyses of Fe2(MoO4)3 were charac- will influence the performance of the developed electrochemical
terized via XRD in Fig. 1A. The XRD patterns of the product can sensor. Fig. S1 (ESI†) displays the electrochemical oxidation of
be indexed to the monoclinic phase Fe2(MoO4)3 structure DA with respect to variation in the concentration of Fe2(MoO4)3.
(JCPDS file Card No. 35-0183) without other possible 2 mg mLꢀ1 of Fe2(MoO4)3 presented the highest oxidation
impurities.50,51 The sharpness of the XRD peak indicates the current for the detection of DA. The effect of the amount of
high crystallinity nature of materials. Raman spectroscopy Fe2(MoO4)3 on the electrode response to 150 mM DA is shown in
analysis was used further to confirm the (Fe2MoO4)3 formation, Fig. S2 (ESI†). The oxidation peak current progressively increases
which is shown in Fig. 1B. The Raman spectrum of the MoO4 with the loading amount (2.0–6.0 mL), and the highest peak
units of Fe2(MoO4)3 was characterized by a triple peak feature at current response appears at 8 mL of Fe2(MoO4)3. Therefore,
995, 972 and 937 cmꢀ1, corresponding to the symmetric 8.0 mL of Fe2(MoO4)3 was selected as the optimal loading volume
stretching mode of the MoQO bonds of three distinct MoO4 in the subsequent electrochemical experiment.
units. The two bands at 785 and 824 cmꢀ1 correspond to the
3.2.1 Electrochemical performance for the detection of DA.
asymmetric stretching vibration mode. A broad feature at The CV technique in Fig. 3A show the bare SPCE and
around 350 cmꢀ1 corresponds to the bending modes of the Fe2(MoO4)3/SPCE in the absence and presence of DA (150 mM).
MoO4 overlaying bands.52,53 The morphology of Fe2(MoO4)3 was No obvious redox peaks were observed on the bare SPCE and
investigated by TEM measurements. The TEM images of Fe2(MoO4)3/SPCE in 0.05 M PBS (pH 7.0) without 150 mM DA,
Fe2(MoO4)3 present a uniform sphere-like structure with good which suggests that no electrocatalytic reaction took on the
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redox currents progressively increase with the concentration of
DA. The result indicates that Fe2(MoO4)3/SPCE has a good
electrochemical activity for the electrochemical sensing of DA.
3.2.2 Effect of scan rate and pH. The effect of the scan rate
on the electrochemical performance of DA at Fe2(MoO4)3/SPCE
was examined by the CV method. Fig. 3C displays the CV curves
of Fe2(MoO4)3/SPCE in 150 mM DA containing 0.05 M PBS
Scheme 2 The redox mechanism of DA.
electrodes. The bare SPCE exhibits quasi-reversible redox perfor- (pH 7.0) at different scan rates from 40 to 240 mV sꢀ1. As the
mance with weak oxidation (Epa) and reduction (Epc) peaks for scan rate increases, the redox peak currents of DA for
DA observed at 0.35 and 0.02 V, respectively. As expected, Fe2(MoO4)3/SPCE increases continuously, suggesting a quasi-
Fe2(MoO4)3/SPCE shows a well-defined quasi-reversible beha- reversible process. The redox peak current of DA had a linear
viour for DA, and the redox peaks are observed at 0.28 V (Epa) dependence on the scan rates with the correlation coefficient of
and 0.03 V (Epc), respectively. Besides, the anodic peak current 0.9975 and 0.9984 (Fig. 3D). The obtained results indicate that
response of DA is about 1.44 fold higher than that of those the electrochemical reaction was controlled by a typical surface-
observed at bare SPCE. The good redox current response at controlled electrochemical process on the Fe2(MoO4)3/SPCE.
Fe2(MoO4)3/SPCE is due to good specific area, better electro- The solution pH is an important parameter for high sensitivity
catalytic activity and more active sites. The electrochemical in the detection system.55–57 The effect of pH on the redox
reaction of DA occurs by exchanging two-electron and two reaction of 150 mM DA at Fe2(MoO4)3/SPCE was investigated by
protons on the surface of Fe2(MoO4)3/SPCE, thus forming the CV method in the pH range from 3.0 to 11.0. As shown in
dopamine-o-quinone (DOQ). The mechanism for the electro- Fig. 4A, the redox peak current of DA increased gradually with
oxidation of DA is depicted in Scheme 2. Fig. 3B shows the CV the increase in the pH of the solution from 3.0 to 7.0, and the
curves of Fe2(MoO4)3/SPCE in the different concentrations of DA maximum redox current was achieved at pH 7.0. With further
ranging from 30 to 150 mM. As shown in the CV signals, the increasing pH, the redox peak current gradually reduced.58–61
Fig. 4 (A) CV curves obtained at Fe2(MoO4)3/SPCE in 150 mM DA containing different pH at a scan rate of 50 mV sꢀ1. (B) Calibration plot of the formal
potential (E00) of DA vs. pH.
Fig. 5 (A) DPV responses at Fe2(MoO4)3/SPCE of various concentrations of DA. (B) Calibration plots of the oxidation peak current vs. different DA
concentrations.
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Table 1 Comparison of Fe2(MoO4)3 with previously reported DA sensors
Electrode materials Methods Linear range (mM) LOD (mM) Ref.
3.2.3 Determination of DA. The DPV technique was
applied to assess the electrochemical performance of
Fe2(MoO4)3/SPCE towards the DA determination. Fig. 5A shows
the DPV signals for various concentrations of DA at Fe2(MoO4)3/
SPCE. The oxidation peak current of DA increased linearly with
the concentration in the range of 0.01–849 mM. The linear range
for DA was determined in the range from 0.01 to 225 mM with
the correlation coefficient of 0.9913, as shown in Fig. 5B. The
limit of detection (LOD) was calculated to be 0.002 mM by
utilizing the formula as shown in previous literature.6,62–71
Table 1 shows the electrochemical comparison of the proposed
sensor with that of previously reported DA sensors. Fe2(MoO4)3/
YVO/GA
Cu/CuxO NPs/PGE DPV
DPV
0.009–89
0.3–53
0.0015
1.06
6
63
CuCrO2–TiO2
Fe3O4@Au
CB-Nafion/p-BDD SWV
NPC
Ni-MOF
DPV
CV
1–230
0.14
64
65
66
67
68
69
70
71
10–1000
0.1–100
30–90
0.2–100
0.1–20
0.05–100
34–125
0.01–225
0.058
0.054
0.0027
0.06
0.007
0.015
0.158
0.002
DPV
DPV
SWV
DPV
DPV
DPV
Poly-ET
Au–C@Ni/BDD
rGO-CMNs
Fe2(MoO4)3
This work
SPCE presents
a
better electrochemical performance
Hence, pH 7.0 was chosen for the subsequent analytical
experiments. The linear plot between the formal potential
and pH was plotted (Fig. 4B). The number of electron was
calculated by the following Nernst equation:62
towards DA with a dynamic linear range and a very low LOD.
The fabricated Fe2(MoO4)3/SPCE sensor is effective for analyzing
DA in biological samples.
3.2.4 Interference and analytical application. The selectivity
of DA electrochemical oxidation on Fe2(MoO4)3/SPCE was
assessed by the DPV method with numerous interferents in
human serum samples. Thus, uric acid (b), ascorbic acid (c),
glucose (d), sucrose (e), caffeic acid (f), catechol (g), iron (h), zinc
2:303RTm
Ep ¼ Ef0ormal ꢀ
pH
nf
where Ep, R, T, m, n, and f are the electric potential, universal (i) and sodium chloride (j) were taken as interfering substances
gas constant, temperature, number of protons, number of for DA. Fig. 6A displays the DPV performances of DA oxidation
electrons, and Faraday constant, respectively. We estimated with a 20-fold excess of b–g and a 50-fold excess of h–j. It can be
the slope value of ꢀ50.6 mV pHꢀ1, which is an equal number seen that common interfering substance lead to a minimum
of protons and electrons process.
relative error (ꢁ5%) in the determination of DA (Fig. 6B).
Fig. 6 (A) DPV signals of Fe2(MoO4)3/SPCE towards DA (a) in the presence of various common interference compounds (b–j). (B) A plot of the current
response of DA (%) with different interfering compounds. (C) DPV signals for the detection of DA in the spiked human serum sample based on
Fe2(MoO4)3/SPCE. (D) Calibration plot of the oxidation intensity against DA.
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Table 2 Determination of DA in human serum samples by Fe2(MoO4)3/
SPCE
Acknowledgements
This work was supported by the Ministry of Science and
Technology, Taiwan (MOST 107-2113-M-027-005-MY3). The
authors are grateful to the Deanship of Scientific Research,
King Saud University, for funding through Vice Deanship of
Scientific Research Chairs. The authors would keenly thank
Dr. Thangavelu Kokulnathan for their outstanding support
throughout the work.
Detected
(mM)
Added
(mM)
Found
(mM)
Recovery
(%)
Samples
Human serum samples
—
—
—
—
—
1.00
3.00
6.00
10.00
15.00
0.99
2.99
5.96
9.98
14.94
99.00
99.70
99.30
99.80
99.60
These results confirmed that Fe2(MoO4)3/SPCE has good
selectivity towards DA.
References
The analysis of DA present in human serum samples was
studied via the DPV method using the Standard addition
approach (Fig. 6C). Human serum samples were diluted
20 times with 0.05 M PBS (pH 7.0). Human serum samples
are free from DA; therefore, injected a known level of standard
DA in human serum samples. The plot for DA at Fe2(MoO4)3/
SPCE in Fig. 6D displays that the oxidation current increased
with the DA concentration in the range from 1 to 15 mM with
the correlation coefficient of 0.9982, and the obtained recovery
results are presented in Table 2. The recovery results of DA in
human serum samples were found in the range from 99.30 to
99.80% (Table 2). These results confirmed that Fe2(MoO4)3 is
the most promising electrode material for the sensitive and
selective detection of DA in real biological samples.
1 S. Madhu, P. Manickam, M. Pierre, S. Bhansali,
P. Nagamony and V. Chinnuswamy, Sens. Actuators, A,
2018, 269, 401–411.
2 Y. Gwon, V. D. Phung, Y. D. Son, J. H. Kim and S. W. Lee,
Electron. Mater. Lett., 2021, 1–7.
3 K. M. Diederen and P. C. Fletcher, Neuroscientist, 2021, 1,
30–46.
4 S. Priyatharshni, D. Navadeepthy, G. Srividhya, C. Viswanathan
and N. Ponpandian, Colloids Surf., A, 2021, 126387.
5 D. Murugesan, K. Moulaee, G. Neri, N. Ponpandian and
C. Viswanathan, Nanotechnology, 2019, 30(26), 265501.
6 T. Kokulnathan, F. Ahmed, S. M. Chen, T. W. Chen,
P. M. Hasan, A. L. Bilgrami and R. Darwesh, ACS Appl.
Mater. Interfaces, 2021, 13, 10987–10995.
7 P. M. Shafi, N. Joseph, R. Karthik, J. J. Shim, A. C. Bose and
V. Ganesh, Microchem. J., 2021, 164, 105945.
8 M. R. Awual, M. M. Hasan, A. Islam, M. M. Rahman,
A. M. Asiri, M. A. Khaleque and M. C. Sheikh, J. Cleaner
Prod., 2019, 231, 214–223.
4. Conclusion
We describe the simple fabrication of an effective and fast
electrochemical sensor for the analysis of DA.
A novel
Fe2(MoO4)3 was synthesized via a hydrothermal method and
used as the sensing material. The sensing material was extensively
examined via X-ray diffraction, Fourier-transform infrared
spectroscopy, transmission electron microscopy, line energy-
dispersive X-ray spectroscopy and elemental mapping. Fe2(MoO4)3/
SPCE exhibits a better electrochemical performance than bare
SPCE, which is attributed to the good surface area, electrocatalytic
activity and active sites. The pH values were highly influenced and
the pH 7.0 was effective for efficient DA detection. Fe2(MoO4)3/
SPCE has proven to be promising for DA detection with low LOD
(0.002 mM) and good linear range (0.01–225 mM). Importantly, the
presence of various coexisting compounds did not adversely affect
during DA detection. Compared to other literature reported in
Table 1, our proposed sensor was a better linear range, LOD and
selectivity. Furthermore, the as-prepared Fe2(MoO4)3/SPCE shows
comparable electrochemical performance for DA sensing in human
serum samples with satisfying recoveries. In the future, our
Fe2(MoO4)3 based sensor shows promising electrochemical
performance as a potential DA sensor.
9 M. R. Awual, J. Environ. Chem. Eng., 2019, 7(3), 103087.
10 M. R. Awual, M. M. Hasan, J. Iqbal, M. A. Islam, A. Islam,
S. Khandaker, A. M. Asiri and M. M. Rahman, J. Environ.
Chem. Eng., 2020, 8(1), 103591.
11 X. Wei, Z. Zhang and Z. Wang, Microchem. J., 2019, 145,
55–58.
12 T. Zhou, Z. Su, Y. Tu and J. Yan, Spectrochim. Acta, Part A,
2021, 252, 119519.
13 U. Nishan, U. Sabba, A. Rahim, M. Asad, M. Shah, A. Iqbal,
J. Iqbal and N. Muhammad, Mater. Chem. Phys., 2021,
262, 124289.
14 P. Li, X. H. Ma, L. Jin and J. Chen, J. Chromatogr. B: Anal.
Technol. Biomed. Life Sci., 2021, 1167, 122582.
15 F. Chen, B. Fang and S. Wang, J. Anal. Methods Chem., 2021,
2021.
16 B. S. Aydin and I. Bulduk, Eurasian J. Bio. Chem. Sci., 2020,
3(2), 116–120.
17 D. Wenk, V. Ignatchenko, A. Macklin, H. Hu¨bner,
P. Gmeiner, D. Weikert, M. Pischetsrieder and
T. Kislinger, Sci. Rep., 2021, 11(1), 1–4.
18 A. Shahat, H. M. Hassan, M. F. El-Shahat, O. El Shahawy and
M. R. Awual, Chem. Eng. J., 2018, 334, 957–967.
19 R. Ramachandran, X. Leng, C. Zhao, Z. X. Xu and F. Wang,
Appl. Mater. Today, 2020, 18, 100477.
Conflicts of interest
There are no conflicts to declare.
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NJC
20 J. Zou, S. Wu, Y. Liu, Y. Sun, Y. Cao, J. P. Hsu, A. T. Wee and 48 A. K. Kulkarni, M. S. Tamboli, D. Y. Nadargi, Y. A. Sethi,
J. Jiang, Carbon, 2018, 130, 652–663.
21 T. Kokulnathan and S. M. Chen, ACS Sustainable Chem. Eng.,
2019, 7(4), 4136–4146.
22 S. Priyatharshni, M. Divagar, C. Viswanathan, D. Mangalaraj
and N. Ponpandian, J. Electrochem. Soc., 2016, 163(8), B460.
S. S. Suryavanshi, A. V. Ghule and B. B. Kale, J. Solid State
Chem., 2020, 281, 121043.
49 M. R. Awual, M. M. Hasan, A. Islam, M. M. Rahman,
A. M. Asiri, M. A. Khaleque and M. C. Sheikh, J. Cleaner
Prod., 2019, 228, 778–785.
23 K. Rajendran, T. Kokulnathan, S. M. Chen, J. A. Allen, 50 K. Seevakan, A. Manikandan, P. Devendran, S. A. Antony
C. Viswanathan and H. A. Therese, Microchim. Acta, 2019,
186(3), 141.
24 B. Sriram, M. Govindasamy, S. F. Wang and X. B. Joseph,
New J. Chem., 2020, 44(25), 10250–10257.
25 T. Kokulnathan, T. W. Chen, S. M. Chen, J. V. Kumar,
S. Sakthinathan and E. R. Nagarajan, Composites, Part B,
2019, 169, 249–257.
26 S. Zou, J. Gao, L. Liu, Z. Lin, P. Fu, S. Wang and Z. Chen,
J. Alloys Compd., 2020, 817, 152785.
and T. Alagesan, Adv. Sci. Eng. Med., 2016, 8(7), 566–572.
51 L. Zhang, X. F. Cao, Y. L. Ma, X. T. Chen and Z. L. Xue, New
J. Chem., 2010, 34(9), 2027–2033.
52 A. Gaur, M. Schumann, K. V. Raun, M. Stehle, P. Beato,
A. D. Jensen, J. D. Grunwaldt and M. Hoj, ChemCatChem,
2019, 11(19), 4871–4883.
53 M. M. Rashad, A. A. Ibrahim, D. A. Rayan, M. M. Sanad and
I. M. Helmy, Environ. Nanotechnol. Monit. Manage., 2017, 8,
175–186.
27 J. N. Baby, B. Sriram, S. F. Wang, M. George, M. Govindasamy 54 H. Znad, K. Abbas, S. Hena and M. R. Awual, J. Environ.
and X. B. Joseph, Nanoscale, 2020, 12(38), 19719–19731. Chem. Eng., 2018, 6(1), 218–227.
28 P. Sundaresan, Y. C. Chen, S. M. Chen, T. W. Chen, P. Latha 55 A. Islam, S. H. Teo, M. R. Awual and Y. H. Taufiq-Yap,
and B. S. Lou, Int. J. Electrochem. Sci., 2018, 13, 10809–10820. J. Cleaner Prod., 2019, 238, 117887.
29 Z. Fan, B. Zhao, S. Wu, H. Wang, T. Cao, T. Zhu, X. Zhang, 56 M. R. Awual and M. M. Hasan, J. Mol. Liq., 2019, 294, 111679.
L. Liu and Z. Tong, J. Mater. Res., 2021, 1–9.
57 M. R. Awual, T. Yaita, T. Kobayashi, H. Shiwaku and
30 M. R. Awual and T. Yaita, Sens. Actuators, B, 2013, 183, 332–341.
S. Suzuki, J. Environ. Chem. Eng., 2020, 8(2), 103684.
31 D. Zhang, R. Zhang, C. Xu, Y. Fan and B. Yuan, Sens. 58 M. R. Awual, A. Islam, M. M. Hasan, M. M. Rahman,
Actuators, B, 2015, 206, 1–7.
32 K. V. Raun, L. F. Lundegaard, P. Beato, C. C. Appel,
A. M. Asiri, M. A. Khaleque and M. C. Sheikh, J. Cleaner
Prod., 2019, 224, 920–929.
K. Nielsen, M. Thorhauge, M. Schumann, A. D. Jensen, 59 M. R. Awual, Chem. Eng. J., 2015, 266, 368–375.
J. D. Grunwaldt and M. Høj, Catal. Lett., 2019, 1.
33 Y. Y. Wu, B. Y. Song, X. F. Zhang, Z. P. Deng, L. H. Huo and
S. Gao, J. Alloys Compd., 2021, 867, 158994.
34 G. Boopathy, M. Keerthi, S. M. Chen, M. J. Umapathy and
B. N. Kumar, Mater. Chem. Phys., 2020, 239, 121982.
60 R. M. Kamel, A. Shahat, W. H. Hegazy, E. M. Khodier and
M. R. Awual, J. Mol. Liq., 2019, 285, 20–26.
61 M. R. Awual, M. M. Hasan, J. Iqbal, A. Islam, M. A. Islam,
A. M. Asiri and M. M. Rahman, Microchem. J., 2020,
154, 104585.
35 B. Arumugam, B. Muthukutty, S. M. Chen, S. K. Ramaraj, J. V. 62 R. D. Crapnell and C. E. Banks, Electroanalytical overview:
Kumar and E. R. Nagarajan, Ultrason. Sonochem., 2020, 66, 104977.
36 J. Lv, X. Liu, X. Zhang and Q. Lu, Mater. Lett., 2021, 290, 129456.
The electroanalytical detection of theophylline, Talanta
Open, 2021, 00037.
37 A. P. Soares, M. F. Portela, A. Kiennemann and L. Hilaire, 63 E. Bahrami, R. Amini and S. Vardak, J. Alloys Compd., 2021,
Chem. Eng. Sci., 2003, 58(7), 1315–1322. 855, 157292.
38 A. A. Alkahlaway, M. A. Betiha, D. Aman and A. M. Rabie, 64 A. K. Keyan, C. L. Yu, R. Rajakumaran, S. Sakthinathan,
Environ. Technol. Innovation, 2021, 22, 101386.
39 A. V. Soares, M. F. Portela, A. Kiennemann, L. Hilaire and
J. M. Millet, Appl. Catal., A, 2001, 206(2), 221–229.
40 J. W. Heo, J. Hyoung and S. T. Hong, Inorg. Chem., 2018, 57,
11901–11908.
C. F. Wu, S. Vinothini, S. M. Chen and T. W. Chiu, Micro-
chem. J., 2021, 160, 105694.
65 H. Guan, B. Liu, D. Gong, B. Peng, B. Han and N. Zhang,
Microchem. J., 2021, 164, 105943.
66 H. Li, K. Zhou, J. Cao, Q. Wei, C. T. Lin, S. E. Pei, L. Ma,
N. Hu, Y. Guo, Z. Deng and Z. Yu, Carbon, 2021, 171,
16–28.
41 V. Nguyen, Y. Liu, Y. Li, S. A. Hakim, X. Yang and W. Chen,
ECS J. Solid State Sci. Technol., 2015, 4(5), M25.
42 M. Niwa and J. Y. Igarashi, Catal. Today, 1999, 52(1), 71–81. 67 P. R. Kasturi, T. K. Aparna, A. L. Arokiyanathan,
43 A. P. Dias, V. V. Rozanov, J. C. Waerenborgh and
S. Lakshmipathi, R. Sivasubramanian, Y. S. Lee and
M. F. Portela, Appl. Catal., A, 2008, 345(2), 185–194.
R. K. Selvan, Mater. Chem. Phys., 2021, 260, 124094.
44 H. Liu and E. Iglesia, J. Phys. Chem. B, 2005, 109(6), 2155–2163. 68 Z. Huang, L. Zhang, P. Cao, N. Wang and M. Lin, Ionics,
45 W. Li, H. Liu and E. Iglesia, J. Phys. Chem. B, 2006, 110(46),
23337–23342.
46 Y. Ding, S. H. Yu, C. Liu and Z. A. Zang, Chem. – Eur. J., 2007,
13(3), 746–753.
2021, 27(3), 1339–1345.
69 A. Kannan, S. Manojkumar and S. Radhakrishnan, Electro-
analysis, 2021, 33, 1–11.
70 H. Li, Y. Guo, S. Zeng, Q. Wei, P. E. Sharel, R. Zhu, J. Cao, L. Ma,
K. Zhou and L. Meng, J. Mater. Sci., 2021, 56(7), 4700–4715.
47 M. Z. Ahmad, I. A. Bhatti, K. Qureshi, N. Ahmad, J. Nisar,
M. Zuber, A. Ashar, M. I. Khan and M. Iqbal, J. Mol. Liq., 71 G. Singh, A. Kushwaha and M. Sharma, J. Electroanal.
2020, 301, 112343. Chem., 2021, 880, 114889.
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