Electropolymerization of cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin) for electrochemical detection of antioxidant-antipyrine

Article abstract of DOI:10.1142/S1088424615500443

Porphyrins are a kind of aromatic molecules possessing unique physic-chemical properties. In this manuscript, it was thus utilized to synthesize 5,10,15-tris(4-aminophenyl)-20-phenylporphyrin and cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin). In addition, conducting cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin) polymeric films were successfully prepared by electropolymerization approach on glassy carbon electrode in the presence of dimethyl formamide solution and 0.1 M tetra-n-butyl ammonium perchlorate at 100 mV/s scan rate. The synthesized polymeric films were evaluated as the active electrode materials to detect an antioxidant (Antipyrine) present in pharmaceuticals and the limit of detection is ～74 μM.

Full text of DOI:10.1142/S1088424615500443

Journal of Porphyrins and Phthalocyanines
J. Porphyrins Phthalocyanines 2015; 19: 1–7
DOI: 10.1142/S1088424615500443
Published at http://www.worldscinet.com/jpp/
Electropolymerization of cobalto(5,10,15-tris(4-aminophenyl)-
20-phenylporphyrin) for electrochemical detection of
antioxidant-antipyrine
Sambandam Anandan*a, Arumugam Manivela, Abdullah M. Asirib
and Jerry J. Wu*c◊
a Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology,
Trichy 620 015, India
b The Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah 21413,
P.O. Box 80203, Saudi Arabia
c Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan
Received 28 September 2014
Accepted 8 January 2015
ABSTRACT: Porphyrins are a kind of aromatic molecules possessing unique physic-chemical
properties. In this manuscript, it was thus utilized to synthesize 5,10,15-tris(4-aminophenyl)-20-
phenylporphyrin and cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin). In addition, conducting
cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin) polymeric films were successfully prepared
by electropolymerization approach on glassy carbon electrode in the presence of dimethyl formamide
solution and 0.1 M tetra-n-butyl ammonium perchlorate at 100 mV/s scan rate. The synthesized polymeric
films were evaluated as the active electrode materials to detect an antioxidant (Antipyrine) present in
pharmaceuticals and the limit of detection is ~74 mM.
KEYWORDS: porphyrin, metalloporphyrin, electropolymerization, antioxidant, electrochemical
detection.
films preparation, which may serve a useful tool as
INTRODUCTION
transducers, chemical and biological sensors [11–15].
The chemistry of porphyrins has attracted the attention
For example, polymeric films of tetrakis(aminophenyl)
of many researchers in different fields of disciplines
porphyrin of Cu(II) and Ni(II) analogs were grown
ranging from medicine to materials science due to the
on conducting glass electrodes and characterized as
presence of conjugated and highly delocalized pi-bonds
electrocatalysts for the reduction of nitrate in two
in its structure [1–7]. Further owing to its high stability
different aqueous media [16]. Co(II) tetra-3-aminophenyl
and redox potential, porphyrin molecules can be easily
porphyrin [Co(II)TAPP] polymeric film [17, 18] has been
modified by coordinating to metal which can act as
studiedasacatalystforoxidationandreductionofNO2 and
mediators in electrocatalytic processes [8–10]. On the
CO2. Also, Lvova et al. [19] developed a novel carbonate-
other hand, electrochemical polymerization of metal
selective potentiometric sensors based on 5,10,15-tris(4-
porphyrins is a well established method for conducting
aminophenyl)-20-phenyl porphyrinates of Co(II) and
Cu(II). Like-wise, Rishpon et al. reported Manganese
loaded tetra(o-aminophenyl)porphyrin polymeric film
SPP full member in good standing
can mediate electron transfer for the electrooxidation
*Correspondence to: Sambandam Anandan, email: sanand@
of glucose oxidase [20]. Furthermore, Wang and
Golden [21] also investigated the catalytic activities of
metalloporphyrins polymeric film towards biological
nitt.edu, tel: +91 431-2503639, fax: +91 431-2500133; Jerry J.
Wu, email: jjwu@fcu.edu.tw, tel: +886 4-24517250 ext. 5206,
fax: +886 4-24517686
Copyright © 2015 World Scientific Publishing Company

2
S. ANANDAN ET AL.
and pharmaceutical compounds, such as ascorbic acid
and penicillamine. The presence of Acetaminophen in
paracetamol was determined by Huang et al. [22] using
the nickel(II) polytetraaminophenylporphyrin electrode.
In this regard, our aim is to detect one of the antio-
xidant (antipyrine; 1,5-dimethyl-2-phenyl-4-pyrazolin-3-
one) present in pharmaceuticals using modified cobalto
(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin) poly-
meric film by electrochemical determination approach.
The main reason for choosing such an antioxidant
here is its frequent use for the treatment of febrile
patients as antondine injection, paracetamol injection,
etc. even though it is a forbidden pharmaceutical [23].
Furthermore, Meng et al. [24] successfully determined
antipyrine in pharmaceutical formulations with recovery
from 96 to 103.5% using Bi2S3 modified glassy carbon
electrode by electrochemical approach. Since electro-
chemical approach is of inherent miniaturization,
high sensitivity, low cost, and low power requirements
compared to laboratory quantification analysis through
high-performance liquid chromatography [25], liquid
chromatography-electrospray tandem mass spectro-
metry [26], capillary electrophoresis [27], etc. the
primary development of electrochemical detection for
pharmaceutical compounds is conducted in this study.
a double beam ultraviolet-visible spectrophotometer
(Model: T90+, PG Instruments Ltd, UK) and Shimadzu
spectrofluorometer (RF-5301 PC), respectively. The
infrared spectra were recorded by Thermo scientific
1
Nicolet iS5 FTIR spectrometer. H NMR spectra were
recorded on BRUKER 400 MHz spectrometer using
CDCl3 as the solvent with chemical shifts reported
relative to the TMS as the internal standard.
RESULTS AND DISCUSSION
Cobalto(5,10,15-tris(4-aminophenyl)-20-phenyl-
porphyrin) monomer and polymer was synthesized as
shown in Scheme 1 (see detailed preparation methods and
characterizationresultsinSupportinginformation).Thatis
by following the available procedures from the literatures
[28, 29]. First, 5,10,15,20-tetraphenylporphyrin (TPP)
was synthesized starting from pyrrole and benzaldehyde.
Then it was allowed to react with excess NaNO2 under
acidic conditions to yield 5,10,15-tris(4-nitrophenyl)-
20-phenylporphyrin (TNPP). The reduction of the TNPP
(nitro group to amino group) was carried out by using
excess SnCl2/HCl mixture, which yields 5,10,15-tris(4-
aminophenyl)-20-phenylporphyrin (TAPP). TAPP on
reaction with Cobalt acetate yields cobalto(5,10,15-
tris(4-aminophenyl)-20-phenylporphyrin) (Co-TAPP).
The electrochemical polymerization of (Co-TAPP) (1 ×
10-3 M)wasperformedinasolutionofdimethylformamide
and 0.1 M tetrabutylammonium perchlorate (TBAClO4)
as the supporting electrolyte at 100 mV/s scan rate. The
synthesized porphyrins and metalloporphyrins were
characterized by NMR (see Figs S1–S3; Supporting
information), FT-IR, and optical and electrochemical
techniques.
FT-IR spectra of TPP, TNPP, TAPP, and cobalt-
triamino phenyl porphyrin (Co-TAPP) monomer and
polymerisshownFig. 1a.TPP(Fig. 1a(a))resultsinstrong
broad peak around 3435 m-1, which indicates the –N-H
stretching of the pyrrole ring. The >C-H stretching of the
phenyl ring was observed around 3022 cm-1. The –C=C–
stretchingofthepyrroleringwasnoticedaround1596cm-1
as broad peak. The peak appeared around 1469 cm-1
is due to –C=N present in TPP. The >C–N appeared
around 1358 cm-1. The >C–H stretching of the pyrrole
appeared around 1151 and 1050 cm-1. Out of plane
bending of the –N-H of the pyrrole was obtained 975 cm-1.
Similar pattern was also noticed in the case of TNPP
(Fig. 1a(b)) and TAPP (Fig. 1a(c)). In TNPP, there was
an extra peak at 1351 cm-1, in addition to the >C-N bond
peak. However, both get merged together and the later
peak appeared like a small shoulder. In the case of TAPP,
the –N-H stretching of the pyrrole ring was seen around
3438 cm-1 with a hump for the primary amine group.
Generally there will be two sharp peaks around 3400 cm-1
for –NH2 group and –N-H stretching of the pyrrole ring,
but in our case it was merged with the pyrrole stretching
EXPERIMENTAL
All chemicals were of the highest purity available
and were used as received without further purification.
Sodium nitrate (NaNO2) and tin chloride (SnCl2) were
purchased from SigmaAldrich. Pyrrole and benzaldehyde
were purchased from Sisco Research Laboratories,
(SRL) Mumbai. Propionic acid was purchased from
Kempesol chemicals. Neutral alumina powder for
column chromatography (Brockmann activity 1) and
silica powder for TLC were procured from Merck.
Tetra-n-butyl ammonium perchlorate (TBAClO4) used
as the background electrolyte was obtained from Fluka,
Switzerland. All the experiments were carried out at
room temperature (25 2°C).
Electrochemical measurements were performed on
a CHI 650C electrochemical workstation (Austin, TX,
USA). A conventional three-electrode system was used
for cyclic voltammetric (CV) and Differential Pulse
Voltammetric (DPV) studies. A platinum wire was
used as counter electrode; a glassy carbon (3 mm) as
working electrode while Ag/AgCl electrode purchased
from BASi (USA) was used as the reference electrode.
Before initiating the experiments, pure argon gas was
purged through the solution for 15 min in order to
remove dissolved oxygen. Prior to recording each cyclic
voltammograms, the GC electrode was polished carefully
and it was standardized using K4[Fe(CN)6]. Dimethyl
formamide was used as the solvent for the CV studies.
The absorption and emission spectra were recorded on
Copyright © 2015 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2015; 19: 2–7

ELECTROPOLYMERIZATION OF COBALTO(5,10,15-TRIS(4-AMINOPHENYL)-20-PHENYLPORPHYRIN)
3
NO2
O
N
N
N
N
Excess NaNO2
Propionic acid
Reflux, 2 hours
+
NH
HN
NH
HN
Trifluoroacetic acid
N
H
O2N
NO2
TPP
TNPP
NH2
NH2
N
Co
N
N
N
SnCl2
(CH3COO)2Co
NH
HN
N
N
CH3Cl, CH3OH
CH3COOH
∆
HCl
H2N
NH2
H2N
NH2
Co(TAPP)
TAPP
NH
N
GCE
N
N
Co
N
0.1 M TBAClO4 in
DMF
HN
NH
n
poly Co(TAPP)
Scheme 1. Figure illustrates the synthesis pathway of cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphyrin) monomer and
polymer
frequency and appeared as small hump. Similar behavior
was noted in the case of Co-TAPP monomer (Fig. 1a(d)).
It is expected that the –N-H stretching would cause some
effect in the Co-TAPP, but there is no dramatic change
in the spectrum. This can be attributed to the peak of
amine group in the phenyl ring which might overlaid and
appear in the region. However compared to monomer,
poly Co-TAPP (Fig. 1a(e)) shows less intense peaks and
in addition lack of free –NH2 bands which illustrate the
polymer formation [30].
The absorbance spectrum of TAPP and Cobalt-
triamino phenyl porphyrin (Co-TAPP) in CHCl3 solution
is shown in Figs 1b and 1c. Before the metalation
reaction, the Soret band (transition a1u → eg) for the
immobilized free porphyrin (TAPP) was observed at
425 nm and the four Q-bands (transition a2u → eg) were
observed at 520, 560, 593, and 652 nm (Fig. 1b). Such
observed bands are almost the same for those of TPP and
TNPP in CHCl3 solution (see Figs S4 and S5; Supporting
information) [31]. Upon metalation, the Soret band
was shifted to 442 nm and the number of the Q-bands
decreased from four to two (one at 556 nm and the other a
weak shoulder at 590–610 nm), which could be observed
in Fig. 1c. This decrease in the number of the Q-bands is
due to the symmetry change of the porphyrin molecule
from D2h to D4h. Furthermore, it is the evidence that the
immobilized porphyrin was metalated by Co(II) [30, 31].
In continuation, under fluorescence spectra TAPP appears
two strong fluorescence peaks around 654 and 715 nm
(Fig. 1d (a)) when it was excited at soret band position
whereas only one fluorescence peak was noticed for
Co(TAPP) at 530 nm (Fig. 1d (b)). The incorporation of
Copyright © 2015 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2015; 19: 3–7

4
S. ANANDAN ET AL.
Fig. 1. (a) FT-IR spectra of TPP (a), TNPP (b), TAPP (c), Co(TAPP) monomer (d) and Co(TAPP) polymer (e). (b) The UV-visible
absorbance spectrum of the TAPP (4.33 × 10-5 M-1) in CHCl3 (inset shows the expanded view of the Q-bands) (c) The UV-visible
absorbance spectrum of the Co(TAPP) monomer (4.33 × 10-5 M-1) in CHCl3 (inset shows the expanded view of the Q-bands).
(d) Fluorescence spectra of TAPP (a) and Co(TAPP) monomer (b) excited at Soret band
the cobalt ion enhances the symmetry of the porphyrin
and hence the LUMO (eg) energy gets increased, which
results in blue shift in the emission band [32].
that amino group is electron donating and hence the
TPP·+ and TPP2+ formation occurs at lower aromatic
potentials while compared to TPP and TNPP (Figs S6
and S7; see Supporting information). Likewise, the cyclic
voltammogram of the Co-TAPP in 0.1 M TBAClO4/
DMF is shown in Fig. 2b. The peak starts around 1.0 V
corresponding to the oxidation of amino group, which
is responsible for the electropolymerization. There is
one quasi-reversible couple at -0.74 V attributed to
the Co(II)/Co(I) process [33–36]. Figure 2c shows the
electropolymerisation of Co-TAPP in GC electrode vs.
Ag/AgCl electrode. The potential was cycled between
-1.2 V to +1.6 V. After successful completion of
50 cycles, the electrode was removed from the cell and
The redox characteristics of free porphyrin (TAPP)
and the Co-TAPP were studied by cyclic voltammetry.
All the voltammograms were recorded in glassy carbon
(GC) electrode in 0.1 M TBAClO4 in DMF (1 mM). The
typical cyclic voltammograms recorded for triamino
derivative (TAPP) in 0.1 M TBAClO4/DMF is shown in
Fig. 2a. It shows two distinct oxidation peaks around 0.8V
and 0.9 V vs. Ag wire as pseudo reference electrode.
These peaks are attributed to the formation of porphyrin,
dication species, and the oxidation of amino phenyl
group in the porphyrin, respectively. It is noted worthy
Copyright © 2015 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2015; 19: 4–7

ELECTROPOLYMERIZATION OF COBALTO(5,10,15-TRIS(4-AMINOPHENYL)-20-PHENYLPORPHYRIN)
5
Fig. 2. The cyclic voltammogram of TAPP (1 mM) (a) and Co(TAPP) monomer (1 mM) (b) vs. Ag/AgCl in a solution of
dimethylformamide and 0.1 M tetrabutylammonium perchlorate as supporting electrolyte at 100 mV/s. (c) Voltammetric response
of the electropolymerization of Co(TAPP) (50 cycles) on a glassy carbon electrode by cycling the electrode potential between -1.2
and +1.6 V vs. Ag/AgCl in a solution of dimethylformamide and 0.1 M tetrabutylammonium perchlorate containing 1 mM of the
complex at 100 mV/s
washed with DMF to remove the physically adsorbed
monomeric Co-TAPP. Then the modified electrode was
subjected for the electrocatalytic detection of antipyrin
molecule. Effect of electropolymerisation cycle in the
catalytic properties has also been studied by recording
10, 25, 50, and 100 cycles (figure not shown). Among
them 50 cycles is given a good catalytic activity.
To evaluate the electrocatalytic activity, poly(Co-
TAPP) modified electrode prepared by 50 potential
cycles was employed for the electrochemical detection
of antipyrine. The typical cyclic voltammograms of the
100 mM antipyrine in 0.1 M phosphate buffer and 0.1 M
KCl were recorded and they matches well with the data
available in the literatures [23, 24]. Figure 3a shows the
oxidation of 100 mM antipyrine in bare GC electrode
and poly(Co-TAPP) modified electrode. The oxidation
of antipyrine starts at 1.0 V in poly(Co-TAPP) modified
electrode, whereas the oxidation process of bare electrode
is 200 mV negative shifts. The decrease in over potential
may be due to the affinity of antipyrine moiety with the
poly(Co-TAPP) modified electrode, which favors the
oxidation process at less positive potential. The increase
in peak current was also seen in the voltammogram. This
is due to the increase in the active surface area of the
electrode and the catalytic ability of the poly(Co-TAPP)
electrode. Further sensitive detection limit of poly(Co-
TAPP) modified electrode towards antipyrine has been
investigated by rapid electrochemical differential pulse
Copyright © 2015 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2015; 19: 5–7

6
S. ANANDAN ET AL.
(a)
(b)
Fig. 3. (a) The cyclic voltammograms of 100 mM antipyrine in bare GC electrode and poly(Co-TAPP) electrode. (b) DPV curves of
antipyrine with different concentrations (100, 200, 300, 400 and 500 mM) at poly(Co-TAPP) electrode (Inset show the corresponding
linear plot)
voltammetry (DPV) method. That is, DPV experiments
were performed using poly(Co-TAPP) modified
electrode containing various individual concentration of
antipyrine (100 to 500 mM). The results (Fig. 3b) show
DPVs of antipyrine oxidation at the surface of poly(Co-
TAPP) modified electrode were linearly dependent on the
antipyrine concentrations (see inset of Fig. 3b) over the
range 100 to 500 mM and the linear regression equation
was (Ip = 1.384C + 0.314; R² = 0.9819, where C is the
concentration of antipyrine) and the detection limit is
estimated to be 74 mM.
In summary, this work provides synthesis and charact-
erization of 5,10,15-tris(4-aminophenyl)-20-phenyl-
porphyrin and cobalto(5,10,15-tris(4-aminophenyl)-20-
phenylporphyrin). The remarkable decrease in number
of q-bands in the absorption spectra and blue shift in
the fluorescence spectra for cobalt complex indicates
that it may be a better candidate for electron mediator
for electrocatalytic studies. Furthermore, synthesized
cobalto(5,10,15-tris(4-aminophenyl)-20-phenylporphy-
rin) polymeric films by electropolymerization approach
exhibits a good electrocatalytic activity towards electro-
chemical detection of antipyrine (limit of detection
at 74 mM). Extension of work is still undergoing in
our research group to provide cobalto(5,10,15-tris(4-
aminophenyl)-20-phenylporphyrin) polymeric films have
any catalytic applications towards other pharmaceuticals.
the support in providing the fabrication and measurement
facilities from the Precision Instrument Support Center of
Feng Chia University is also acknowledged.
Supporting information
A full list of synthesis pathway of cobalto(5,10,15-
tris(4-aminophenyl)-20-phenylporphyrin) monomer and
polymer and figures (Figs S1–S7) are given in the
supplementary material. This material is available free of
chargeviatheInternetathttp://www.worldscinet.com/jpp/
jpp.shtml.
REFERENCES
1. The Porphyrin, VI(a), VII(b), Dolphin D. (Ed.)
Academic Press: New York, 1978.
2. The Porphyrin Handbook, Applications: Past, Present
and Future, Vol. 6, Kadish KM, Smith KM and
Guilard R. (Eds.) Academic Press: London, 2000.
3. Amstrong NR. J. Porphyrins Phthalocyanines
2000; 4: 414–417.
4. Suslick KS, Rakow NA, Kosal ME and Chou JH. J.
Porphyrins Phthalocyanines 2000; 4: 407–413.
5. Kim D and Osuka A. J. Phys. Chem. A 2003; 107:
8791–8816.
6. Zhang ZJ, Hou SF, Zhu ZH and Liu ZF. Langmuir
2000; 16: 537–540.
Acknowledgements
7. Li DQ, Swanson BI, Robinson JM and Hoffbauer
MA. J. Am. Chem. Soc. 1993; 115: 6975–6980.
8. Balzani V and Scandola F. Supramolecular Photo-
chemistry, Ellis Horwood: Chichester, 1991.
9. Shi C and Anson FC. J. Am. Chem. Soc. 1991; 113:
9564–9570.
The research described herein was financially supported
bytheDepartmentofScienceandTechnology,India(GITA/
DST/TWN/P-50/2013) and National Science Council
(NSC), Taiwan (NSC-102-2923-035-001-MY3), under
the India-Taiwan collaborative research grant. In addition,
Copyright © 2015 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2015; 19: 6–7

ELECTROPOLYMERIZATION OF COBALTO(5,10,15-TRIS(4-AMINOPHENYL)-20-PHENYLPORPHYRIN)
7
10. Steiger B, Shi C and Anson FC. Inorg. Chem. 1993;
25. Kitzman J, Martin J, Holley J and Huber W.
J. Chromatogr. 1988; 437: 306–310.
32: 2107–2113.
11. Czuchajowski L, Bennett JE, Goszczynski S,
Wheeler DE, Wisor AK and Malinski T. J. Am.
Chem. Soc. 1989; 111: 607–616.
26. Annola K, Keski-Rahkonen P, Vähäkangas K and
Lehtonen M. J. Chromatogr., B: Anal. Technol.
Biomed. Life Sci. 2008; 876: 191–197.
12. Jin J, Miwa T, Mao L, Tu H and Jin L. Talanta 1999;
48: 1005–1011.
27. Perrett D and Ross G. J. Chromatogr. A 1995; 700:
179–186.
13. N-4 Macrocyclic Metal Complexes, Zagal JH,
Bedioui F and Dodelet JP. (Eds.) Springer: New
York, USA, 2006.
28. Luguya R, Jaquinod L, Fronczek FR, Graca M,
Vicenta H and Smith KM. Tetrahedron 2004; 60:
2757–2763.
14. Zheng L,Ye D, Xiong L, Xu J, Tao K, Zou Z, Huang
D, Kang X, Yang S and Xia J. Analytica Chimica
Acta 2013; 768: 69–75.
15. Muthukumar P and Arbaham John S. Electrochi-
mica Acta 2014; 115: 197–205.
29. Doppelt P, Fischer J and Weiss R. Inorg. Chem.
1984; 23: 2958–2962.
30. Uygun A, Myjavcova R, Yavuz AG, Ruppel JV,
Fields KB and Frankhauser A. Electroanalysis
2011; 23: 1158–1167.
16. Armijo F, Isaacs M, Ramırez G, Trollund E, Cana-
les J and Aguirre MJ. J. Electroanal. Chem. 2004;
566: 315–322.
17. Dreyse P, Ramırez G, Riquelme A and Isaacs M. J.
Chil. Chem. Soc. 2006; 51: 923–926.
31. Zhang X, Li Y, Qi D, Jiang J, Yan X and Bian Y.
J. Phys. Chem. B 2010; 114: 13143–13151.
32. Sun X, Chen G and Zhang J. Dyes Pigm. 2008; 76:
499–501.
33. The Porphyrins Handbook, Metalloporphyrins in
Nonaqueous Media: Database of Redox Poten-
tials, Kadish KM, Smith KM and Guilard R. (Eds.)
Academic Press: New York, 2000.
34. Richter-Addo GB, Hodge SJ,Yi GB, Khan MA, Ma
T, Caemelbeeke EV, Guo N and Kadish KM. Inorg.
Chem. 1996; 35: 6530–6538.
35. D’Souza F, Villard A, Caemelbeeke EV, Franzen
M, Boschi T, Tagliatesta P and Kadish KM. Inorg.
Chem. 1993; 32: 4042–4048.
18. Kilmartin PA, Zou H and Waterhouse AL. J. Agric.
Food Chem. 2001; 49: 1957–1965.
19. Lvova L, Paolesse R, Di Natale C, D’Amico A and
Bergamini A. Int. J. Electrochem. 2011; 1–8.
20. Rishpon J, Rosen I, Harth R, Ozer D and Bettelheim
A. J. Electroanal. Chem. 1991; 307: 293–298.
21. Wang J and Golden T. Anal. Chim. Acta, 1989; 217:
343–351.
22. Huang SS, Tang H and Li BF. Mikrochim. Acta
1998; 128: 37–42.
23. Bashkatova NV, Korotkova EI, Karbainov YA,
Yagovkin AY and Bakibaev AA. J. Pharm. Biomed.
Anal. 2005; 37: 1143–1147.
36. Behar D, Dhanasekaram T, Neta P, Hosten CM,
Ejeh D, Hambright P and Fujita E. J. Phys. Chem.
A. 1998; 102: 2870–2877.
24. Meng X, Xu Z, Wang M, Yin H and Ai S. Anal.
Methods 2012; 4: 1736–1741.
Copyright © 2015 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2015; 19: 7–7