A copper hexacyanocobaltate nanocubes based dopamine sensor in the presence of ascorbic acid

Article abstract of DOI:10.1039/c6ra05810h

A novel copper hexacyanocobaltate based sensor was developed and its electrocatalytic behavior towards the oxidation of dopamine (DA) was demonstrated. Among the Prussian blue analogues, copper hexacyanocobaltate (CuHCC) exhibits unique electrochemical responses due to its bimetallic combination of copper and cobalt. As-prepared CuHCC shows a well-defined cubic structure with an average size of around 252 nm, which was confirmed by XRD and FE-SEM. Raman spectroscopy confirmed the coordination behavior of both the metal and ligand in CuHCC, which existed as Co^III-CN-Cu^II and Co^II-CN-Cu^III. The as-prepared CuHCC was used for the first time in DA detection and provided a better platform as a DA sensor. The electrocatalytic activity of CuHCC towards dopamine was examined by cyclic and differential pulse voltammetry. The CuHCC fabricated sensor shows a wide linear range from 0.1 to 350 μmol L^-1 and low detection limit of 19 nmol L^-1. The sensor reported herein displays excellent sensitivity, high stability and appreciable reproducibility for DA oxidation.

Full text of DOI:10.1039/c6ra05810h

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Nanocubes of copper hexacyanocobaltate based dopamine sensor
in presence of ascorbic acid
N. Karikalan,a M. Velmurugan,a S.M. Chen*a and K. Chelladurai b
Received 00th January 20xx,
Accepted 00th January 20xx
A novel copper hexacyanocobaltate based sensor was developed and demonstrated its electrocatalytic
behavior towards the oxidation of dopamine (DA). Among the Prussian blue analogues, copper hexacyanocobaltate
(CuHCC) exhibits unique electrochemical responses by its bimetallic combination of copper and cobalt. As-prepared CuHCC
shows a well defined cubic structure with an average size around 252 nm that confirmed by XRD and FE-SEM. Raman
spectra confirmed the coordination behavior of both metal and ligand in CuHCC which existed as CoIII-CN-CuII and CoII-CN-
CuIII. The as-prepared CuHCC was used for the first time in DA detection and it was provided a better platform for DA
sensor. The electrocatalytic activity of CuHCC towards dopamine was examined by cyclic and differential pulse
voltammetry. The CuHCC fabricated sensor shows a wide linear range from 0.1 to 350 µmol L–1 and low detection limit of
19 nmol L–1. The present reported sensor displayed an excellent sensitivity, highly stable and appreciable reproducibility
for DA oxidation.
DOI: 10.1039/x0xx00000x
www.rsc.org/
and biocompatibility.14
1. Introduction
The recent studies exhibiting the carbonaceous materials and
Dopamine (DA) is a neurotransmitter plays a vital role in central
nervous system and peripheral nervous system.1 Deficiency of DA
leads the human to Parkinson's disease, attention deficit
hyperactivity disorder, schizophrenia and addiction.2 In particular,
Parkinson’s disease, a degenerative disease of the nervous system
noticed by shiver, muscular rigidity, slow and imprecise movement.3
Therefore, the determination of DA attains considerable
importance in sensor application.4 Several methods have been
employed to detect the DA such as electrochemical,
chromatography, colorimetric, fluorometry, chemiluminescence
and electrophoresis.5-10 Among all, electrochemical detection
provides foremost platform to quantify the DA in real samples via
its fast response and low cost systems. However, the strong
influences of other interferents in physiological sample remains
challenging, especially ascorbic acid (AA) and uric acid (UA)
trespassing in real sample analysis.11 Moreover, the high
concentration of AA (0.2 – 0.5 mmol L-1) in physiological samples
are highly interfere with DA (10-8 – 10-6 mol L-1).12 Hence, the hired
materials are highly selective for the detection of DA in presence of
AA and UA because these analytes are highly influences in the
determination of DA.13 On the other hand, the materials should
have high electrochemical active area, stability, structural flexibility
metal oxides manifest the significant activity towards the
nanomolar detection of DA.15-17 Moreover, the Prussian blue (PB)
analogues received remarkable attention in sensors field, due to
their electron transport mechanism and controllable size.18 The
electrochemical properties of most metal hexacyanoferrates such
as NdHCF, AgHCF, SnHCF, CoHCF, NiHCF and CuHCF are extensively
studied till date for the determination of AA, DA or UA. 19-24 These
materials explored excellent electrocatalytic activity to AA, DA and
UA with selective and simultaneous performance. However, for our
knowledge, metal hexacyanocobaltates based materials are not
evaluated comprehensively. Moreover, copper based compounds
exhibit reasonable performance towards DA detection particularly
oxides of copper.25 Previously, copper and cadmium
hexacyanocobaltate was studied towards carcinoembryonic antigen
(CEA), alpha-fetoprotein (AFP) and RNA detection.26 These report
concluded that the hexacyanocobaltate based materials could be a
sensitive substrate for biomolecules detection.
Hence, the present study we have concentrated on copper
hexacyanocobaltate (Cu3[Co(CN)6]2) for selective detection of DA
oxidation in physiological pH range (pH 7.2). Furthermore, the cubic
crystal morphology of CuHCC was characterized by FESEM, XRD and
Raman spectroscopy. To the best our knowledge, this the first time
report to study the electrochemical behaviour of CuHCC towards
the DA oxidation. In addition, the selectivity of CuHCC is well
appreciated towards the DA oxidation in presence of the strong
interferrents such as AA and UA. Moreover, the performance of
CuHCC was demonstrated in real samples such as dopamine
injection, urine, blood and blood serum. The nanomolar detection
Electroanalysis and Bioelectrochemistry Lab, Department of Chemical Engineering
and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-
Hsiao East Road, Taipei 106, Taiwan, Republic of China.
Taipei 106, Taiwan, Republic
of China.
E-mail: smchen78@ms15.hinet.net; Fax: +886-2-27025238;
Tel: +886-2-27017147
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of DA on CuHCC/GCE was evaluated by voltammetric method. The
electrocatalytic range of DA oxidation on CuHCC/GCE exhibited
from 0.1 to 350 µmol L–1. The fabricated sensor can able to sense
the minimum level of DA detection is around 19 nmol L–1. The
proposed sensor shows a highly sensitive substrate for DA sensor
compare to other prussian analogues.
2. Experimental
2.1. Materials
Potassium hexacyanocobaltate (K3(Co(CN)6)), Copper chloride
dihydrate (CuCl2.2H2O), Dopamine, Uric acid, Ascorbic acid,
Potassium hydrogen phosphate and dihydrogen phosphate were
obtained from Aldrich chemical Co. and used as received.
Scheme 1. Proposed design of final device for dopamine sensor
electrode modified by CuHCC nanocubes.
2.2. Apparatus
Results and discussion
X-ray diffraction pattern of the compound were performed using a
XRD, XPERT-PRO (PANalytical B.V., The Netherlands) with CuKα
radiation (λ=1.5406 Å). FESEM images were taken by FEG QUANTA
250. Raman measurement was recorded using NT-MDT, NTEGRA
SPECTRA. CHI 1205B electrochemical analyzer (CH Instruments,
USA) was used to study the cyclic voltammetry and
chronoamperometry. Differential pulse voltammetry (DPV)
measurements were performed using CHI 900 (CH Instruments,
USA). A conventional three electrode system has been employed
for the catalysis where glassy carbon working electrode (0.07 cm2),
platinum wire auxillary electrode and Ag/AgCl/3 M KCl reference
electrode.
3.1 Characterization of CuHCC
The hexacyanometalates form the zeolitic compounds with the
transition metals, mainly Prussian blue which is studied extensively.
The common formula of Prussian blue analogue is
AxMy[M(CN)6]z·nH2O (where A = alkali metal cation, M = transition
metal cation either both are same or different). Crystal model of
Cu3[Co(CN)6]2 was shown in fig. 1 in which Cu2+ is in high-spin state
coordinated by N and Co3+ is in low-spin state and coordinated by C.
Mostly metal ions are sharing the edge site of cube and cyanide
ions bridging the metal ions.27 The electronic structure and
coordination sites of Cu3[Co(CN)6]2 was analyzed by Fourier
Transform Infrared (FT-IR) and Raman spectroscopy.
2.3. Synthesis and fabrication of CuHCC for DA sensor
The described material was synthesized by precipitation method,
where potassium hexacyanocobaltate (K3(Co(CN)6)) was added to
copper chloride dihydrate (CuCl2.2H2O). In this method, we follow
the 3:2 ratio of metal and complex ligand; this is furnish the
compound without potassium in its lattice. Here, 300ml of 0.05 M
CuCl2.2H2O added to the 200ml of 0.05M (K3(Co(CN)6)), suddenly
the solution turns to colloids of sky blue color mixture of
Cu3[Co(CN)6]2 crystals and this mixture was maintained in the
vigorous stirring condition for an hour. Finally the compound was
collected by centrifugation and washed several times with milli-Q
(18Mꢀ) water and dried in an oven for overnight at 45 °C. After
that, the sample was stored in a closed container to avoid the
moisture and named as CuHCC. In order to fabricate the CuHCC
modified electrode, the CuHCC was redispersed in mill-Q water
about 5 mg mL–1 and further sonicated 10 min for uniform
suspension. About 8 µL of this suspension was drop casted on GCE
and then dried well at 50 °C for stable film formation. These
successfully fabricated sensor material can further be used for DA
sensor. The screen printed carbon electrode (SPCE) was used as a
disposable sensor electrode. We have modify that SPCE by CuHCC
and directly applied for the dopamine determination. The CuHCC
disposable DA sensor was shown in Scheme 1.
Fig. 1 Schematic representation of copper hexacyanocobaltate
lattice structure.
As shown in fig. 2(a), the FT-IR results provides the information
about the octahedral Co(CN)6 ligand, where observed absorption
bands are related to the vibrations of –CN, Co-C and water.28 In this
crystal lattice, water molecules occupies in the zeolitic site which
clearly inferred from the FT-IR stretching and bending vibrations of
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around 3435 and 1604 cm–1, usually former peak appeared as sharp evidences the mixture of mixed valance states are present in the
band but here it was broad due to the movement of hydrogen compound.
bonded water.29 Commonly all hexacyanocobaltate shows the
The structural behavior of CuHCC was studied by powder X-ray
vibration around 430-470, this sharp peak exhibited the bonding
diffraction pattern (fig. 2(c)). Previously, A. Ratuszna and G. malecki
information of Co-C in the Co(CN)6. Finally, the stretching frequency
has established the XRD patterns for CuHCC.48 That is closely
around 2189 confirms the –CN bridging between two metals,
matched with the as-prepared compound CuHCC, which crystallizes
among the transition metal cobalitcyanides copper reveals high
stretching frequency due to strong bond between the Cu and N.30
in Fm-3m space group with a =10.49 Å. The peaks observed at,
25.3o, 29.7o, 36.0o, 40.6o, 44.8o, 51.8o, 55.6o, 58.8o, 68.1o and 70.9o
The cyanide ion bridging is familiar in hexacyanometalates where it
are attributed to (200), (220), (311), (400), (420), (422), (440), (600),
was coordinated to metal by both sides of cyanide ion (i.e., carbon
(620), (640) and (642) planes. These peaks are revealing the
end and nitrogen end). In carbon side, the cyanide ion act as a
compound has high crystalline nature and the rough baselines
strong ligand hence it makes low-spin configuration towards
indicate some of crystals being squeezed or crushed. The
predominant peak observed at 17.8o corresponds to (200) plane
metals. Conversely, nitrogen side it will act as a weak ligand
Fig. 2 (a) Infra-red spectra, (b) Raman spectra, (c) Powder XRD patterns and (d) FE-SEM images of the as-prepared CuHCC.
compare to carbon so it makes high-spin configuration towards which denotes most of the compound exposes in this plane hence
metals. However, different oxidation states are possible in the crystallite size was calculated from this plane using debye-
+
+
Mδ −C≡N−Mδ coordination such as CoII-CN-CuII, CoIII-CN-CuII, CoII-
scherrer formula. The calculated crystallite size was 278 nm for this
plane and average crystallite size was 252 nm. Most of the prussian
blue analogues disclose the discrete cubic structure with average
particle size of 70-700 nm.31-34 CuHCC also shows cubic structure
which further confirmed by FE-SEM, as shown in fig. 2(d). CuHCC
exhibited uniformly distributed cubes by distinct boundary with an
average particle size of 250-280 nm, which was matched with
calculated crystallite size (from XRD).
CN-CuIII and CoIII-CN-CuIII.
The Raman spectra is a useful tool to assess the different
valance states. Fig. 2(b) depicts the Raman spectra of CuHCC where
the observed peak at 2200 and 2218 cm-1 which is corresponding to
the cyanide ion stretching. The two peaks are merged and
pronounces on broad peak, here the frequencies at 2088 and 2134
cm-1 attributed to the CoIII-CN-CuII and CoII-CN-CuIII, these result
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anodic peak for the account and we confirmed the DA oxidation is
fully controlled by diffusion process from this plot.
3.2 Electrocatalytic oxidation of dopamine
The electrocatalytic behavior of CuHCC was studied towards the
electro-oxidation of DA. Fig. 3(a) shows the cyclic voltammetry (CV)
responses of bare and CuHCC modified GCEs in 100 µmol L-1 DA
containing 0.1 M phosphate buffer solution (pH-7.2) at a scan rate
of 50 mV/s. A pair of quasi reversible peak was obtained for both
electrodes however the bare GCE reveals better curvature for both
anodic and cathodic peaks. Other than bare GCE, most
carbonaceous materials were exhibiting a strong quasi reversible
peak for dopamine oxidation. The anodic (Epa) and cathodic (Epc)
peak potential of bare and CuHCC modified GCEs were 0.35, 0.22
and 0.07, 0.07 respectively. The peak-to-peak separation was found
to be 280 mV for bare GCE whereas CuHCC modified electrode
exhibited only 150 mV because of the low onset potential
(oxidation) of CuHCC modified electrode. Moreover, the oxidation
peak current of DA is five times higher for CuHCC modified
electrode compare to bare GCE. The reason is bi-metallic nature of
CuHCC provides the suitable binding site (Co-CN-Cu) to DA where it
can be easily adsorbed on the surface of CuHCC modified electrode.
Moreover, the low spin configuration of Co3+ (d6) is stable in lattice
by the completely filled t2g orbital meanwhile the high spin
configuration of Cu2+ (d9) remains unstable due to the vacant
orbital. Hence it needs one electron to achieve the fully occupied
orbital configuration therefore it oxidizes DA with the aid of Co3+
however to recover the lattice geometry, K+ ions inserted into
lattice (from electrolyte) and reduce the Co3+ to Co2+ (see the
mechanism in scheme 2). Fig. 3(a) (inset) depicts the CV responses
of bare and CuHCC modified GCEs in absence of DA, where the
CuHCC modified electrode exhibits a high capacitive background
current and a reduction peak at 0.14 V vs Ag/AgCl (onset potential)
compare to bare GCE. This value suggested that the as-prepared
compound was performed well when compared with bare GCE.
Fig. 3 (a) CVs recorded for the 100 µmol L-1 DA at the bare GCE
(blue) and CuHCC modified GCE (red) at a scan rate of 50 mV s-1
and the inset shows CVs obtained in the absence of DA at bare
and CuHCC modified GCE in 0.1 mol L-1 PB (pH 7.2) at the scan rate
of 50 mV s-1. (b) CV of the CuHCC modified GCE in 100 µmol L-1 DA
containing 0.1 mol L-1 PB at different scan rates from 20 to 300 mV
3.3 Effect of scan rate
The effect of scan rate is performed for CuHCC modified
electrode in 100 µmol L-1 DA containing 0.1 M PB by CV at a scan
rate of 50 mV/s and shown in fig. 3(b). The redox peak current of
the DA oxidation was linearly increases over the increasing scan
rate ranging from 20 to 300 mV/s. However, the redox peak
potential slightly shifts towards positive and negative side for the
anodic and cathodic reactions respectively. This is due to the
increase of internal resistance caused by increasing the DA
s-1 and the inset shows the plot of Ipa vs. ν1/2
.
3.4 Determination of dopamine
Differential pulse voltammetry (DPV) provides a high sensitive
concentration, here DA adsorbs on electrode surface and forms a current and better detection compare to CV, hence the
thin layer (unreal) which restricts the bulk electrolytes movement determination of DA was carried out by using DPV. Fig.4 depicts the
from the bulk solution to diffusion layer (inner and outer Helmholtz
DPV responses of CuHCC modified electrode for the additions of
plane). The anodic peak current (Ipa) of the DA oxidation was different concentration of DA from 0.1 to 650 µmol L-1. It can be
plotted against the square root of scan rate in fig. 3(b) (inset), this seen that a sharp DPV response was observed for the addition of
0.1 µmol L-1 DA and the current response increase linearly with
follows the good linearity with the correlation coefficient of 0.9966.
The cathodic peak current (Ipc) was interfering with compound’s increasing the concentration of DA. The DPV response of CuHCC
reduction peak hence this peak is merged with cathodic peak of DA modified electrode was linear over the concentration ranging from
oxidation when increasing scan rate. Therefore we acquire only the 0.1 to 350 µmol L-1 (fig. 4(inset)) with the correlation coefficient of
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R2=0.9954. This study stated that the highest linear range of 0.1 to positively charged nature (pKa = 8.87) in physiological pH (7.2 to
350 µmol L-1 and lower limit detection (LOD) of 0.019 µmol L-1 was 7.4). According to crystal field theory, the strong ligands donate
achieved by CuHCC towards the detection of DA. The performance their charges to metal ions hence it will be acquire negative charge.
of the fabricated sensor was compared with recently reported DA Therefore, the negative charge of the metal ions provides the space
sensors and the comparative results are shown in Table. 1. In to DA adsorption (positively charged nature). At the same time it
addition, the CuHCC nanocubes modified electrode has also been repels the negatively charged nature of AA. Therefore protonated
compared with other copper nanostructures (nanoparticles, DA was simply adsorbs on the surface of CuHCC modified electrode
nanoleaf, nanocubes and microspheres) based DA sensors (see and oxidized, which manifests a large oxidative current response
Table. 1). The analytical comparison of our proposed sensor clearly (Scheme 2). On the other hand, CuHCC modified electrode oxidizes
reveals that the CuHCC nanocubes modified electrode has low LOD UA also however it comes at different potential with sharp peak
and better linear range for the detection of DA compare to other current. But the electrocatalytic performance of UA is not much
modified electrodes. The mechanism and superior performance of better compare with previous reports, so present study only
CuHCC modified electrode was elaborately explained in above part.
concentrate on the detection of DA.
3.5 Effect of interference and selectivity
AA, DA and UA are playing vital role in human health and it is
well known that electrochemically all are response in closed
potential differences.43 Hence the determination of DA in presence
of AA and DA is quite important. Electrochemical detection of these
compounds has more interest but some cases AA highly interfere
with DA. Commonly, AA co-exists with DA in body fluids and also
present in higher concentrations compare with DA. Here, we
demonstrated the selective detection of DA by CuHCC modified
electrode in presence of AA and UA in PB with the 100 fold and 10-
fold excess of AA and UA concentrations compare to DA. Fig. 5(a)
shows the CVs of DA oxidation in presence of different interfering
analytes such as AA and UA, where AA does not interfere with DA
oxidation. This is clearly inferred from the fig. 5(a), the DA and AA
mixture exhibits the current responses merged over the DA
oxidation curve. Hence there is no electrocatalytic response
observed for AA, this is may be due to the negatively charged
nature of AA (pKa = 4.10) at pH 7.0, whereas DA attributed to the
Scheme 2. Possible mechanism for the detection of DA and the
electrochemical response of AA on CuHCC modified electrode.
Electrode
Electrolyte
PBS (pH 7)
PBS (pH 7)
Method
DPV
Linear Range µmolL-1
4–100
Detection Limit µmolL-1
Ref
37
38
39
35
40
12
11
36
41
13
23
42
Graphene/GCE
TiO2/graphene/GCE
SZP/MB
2.64
2
DPV
5–200
Tris-HCl (pH 7.4) DPV
6–100
1.7
CuO/MWNTs/Nafion/GCE
SWCNT/Fe2O3/GCE
GO/GCE
PBS (pH 6)
PBS (pH 7)
B-R (pH 5)
PBS (pH 7)
PBS (pH 6)
DPASV
1.0–80
0.4
SWV
DPV
DPV
DPV
3.2–31.8
0.36
0.27
0.1
1.0–15
Pt/RGO/MnO2/GCE
CuO/CPE
1.5–215.56
0.3–1.4, 2–20
0.10–12.0
0.1–50, 50–600
0.1-4.3, 4.3-9.6
0.1–200
0.055
0.04
0.024
0.021
0.0194
MnO2/chitosan/AuE
KNO3 (pH 4 to 9) CA
PBS (pH 7)
PBS (pH 7)
PBS (pH 6)
PBS (pH 6.5)
DPV
γ-WO3/GCE
NiHCF/PNH/AuE
CHI/VSG/PPy scaffold
Cu nanocubes/GCE
DPV
DPV
CA
DPV
CA
DPV
CA
DPV
0.5–300, 300–2000
0.001–0.1, 0.5–200
0.099–708
1–7.5, 7.5–140
1000-8000
0.2
0.002
0.0396
0.5
100
0.019
44
45
46
Cu2O HMS/CB/GCE
CuO nanoleaf
ZnO nanorod/flower like CuO/AuE
CuHCC nanocubes/GCE
PBS (pH 5.7)
PBS (pH 8)
PBS (pH 7.3)
PBS (pH 7.2)
47
0.1–350
This work
Table 1. Comparison for the performance of DA oxidation between CuHCC/GCE and other modified electrodes.
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Fig. 4 DPV of the CuHCC modified electrode for the additions of
different concentration of DA from 0.1 to 650 µmol L-1 and the
inset shows the calibration plot of the current vs. concentration
(0.1 to 650 µmol L-1).
Apart from AA and UA, other biological interference also
affecting the DA oxidation, however AA and UA are essential. We
analyzed the other interference also, such as NaCl, KCl,
epinepherine, norepinepherine, serotonin, glucose and L-tyrosine.
Fig. 5(b) depicts the chronoamperometric responses of DA
oxidation with various interferents, where the fabricated sensor
was selectively oxidize only DA in presence of other interference in
high concentrations.
Fig. 5 (a) CVs of CuHCC modified electrode in presence of AA and
UA in DA containing PB (pH 7.2) with the 100 fold and 10-fold
excess of AA and UA concentrations. (b) Chronoamperometric
response of CuHCC modified electrode for the addition of 100
µmol L-1 DA with the additions of interferents (a) NaCl, (b) KCl, (c)
epinepherine, (d) norepinepherine, (e) serotonin, (f) glucose and
(g) L-tyrosine in 0.1 mol L-1 PB (pH 7.2); Applied potential = 0.2 V
(Ag/AgCl).
3.6 Determination of DA in real sample
To study the practicability of CuHCC fabricated sensor in real
sample analysis, the dopamine hydrochloride injection was
explored. The stock solution of DA injection sample was made by
appropriate dilution with 0.1 M PBS (pH 7.2) and used for detection
of DA. The recovery of DA was calculated by standard addition
method, as reported previously. The obtained recoveries of DA
were summarized in Table. 2 and the recovery were in the range
from 98.9 % to 102.2 %. The results confirmed that the proposed
CuHCC modified electrode has appropriate recovery towards DA,
and could be used for real time sensing of DA in pharmaceutical
formulations. In addition, we have analysed the DA in other real
samples (urine, blood and blood serum) and gathered appropriate
recoveries that was given in Table. 3. We have provided the design
of final device that can be used for the miniature applications
(scheme 1).
Sample Added
(µM)
Detecteda
(µM)
Recovery
(%)
RSDb (%)
1
2
3
5
5.11
102.2
2.1
1.6
1.9
10
20
9.89
98.9
99.8
19.96
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Table 2. Determination of DA oxidation in diluted dopamine 10. J. Wang, M. P. Chatrathi, B. Tian and R. Polsky, Anal. Chem.,
a
hydrochloride injection using CuHCC modified GCE. Standard
2000, 72, 2514.
b
addition method;
measurements.
Relative standard deviation for three 11. B. Yang, J. Wang, D. Bin, M. Zhu, P. Yang and Y. Du. J. Mater.
Chem. B, 2015, 3, 7440.
12. F. Gao, X. Cai, X. Wang, C. Gao, S. Liu, F. Gao and Q. Wang,
Biological
samples
Blood
Blood serum
Urine
Added
(µM)
10
10
10
Detecteda
(µM)
Recovery
(%)
RSDb (%)
Sens. Actuators B, 2013, 186, 380.
13. A. C. Anithaa, N. Lavanya, K. Asokan and C. Sekar, Electrochim.
Acta, 2015, 167, 294.
9.68
9.94
9.82
96.8
99.4
98.2
3.2
1.8
2.8
14. V. Hariharan, S. Radhakrishnan, M. Parthibavarman, R.
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a
b
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Relative standard deviation for three measurements.
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In summary, the novel CuHCC modified electrode has been used for
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µmol L–1) and lower LOD (19 nmol L–1) for DA compare to previously
reported Prussian blue analogues modified electrodes. The
proposed sensor has high selectivity towards the DA in the
presence of excess amount of UA, AA and other neurotransmitters.
The good recovery of DA in commercial dopamine injection samples
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This project was supported by the National Science Council and the
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Title of content (TOC)
A highly selective and sensitive dopamine sensor was demonstrated based on nanocubes of
copper hexacyanocobaltate in the presence of ascorbic acid.