Highly selective potentiometric oxalate ion sensors based on Ni(II) bis-(m-aminoacetophenone)ethylenediamine

Article abstract of DOI:10.1002/cjoc.201090198

A plasticized PVC (polyvinyl chloride) membrane based oxalate ion selective electrode has been developed by using the condensation product of m-aminoacetophenone and ethylenediamine. The transition metal complexes of the ligand N,N′-bis(m-aminoacetophenene)ethylenediamine (L) were synthesized and incorporated as ionophore for the synthesis of oxalate ion selective electrodes. Most appropriate result in terms of dynamic range, detection limit and response behavior was determined for the Ni(II) bis-(m-aminoacetophenone) ethylenediamine complex. The electrode demonstrated higher selectivity for oxalate ion with improved performance as compared to other carriers reported in past. The electrode shows Nernstian slope of (-28.5 ± 0.4) mV?decade¹ with improved linear range of 1×10 ¹-1 × 10⁷ mol?L¹, with a comparatively lower detection limit in the pH range of 5-10.5, giving a relatively fast response within 10 s and reasonable reproducibility. The selectivity coefficient was calculated using matched potential method and fixed interference method. The lifetime of the electrode was found to be nearly 2 months. The response mechanism and the interaction of oxalate ion with the complexes have been discussed by UV-visible spectroscopic technique. Further the electrode was also successfully applied to determine the oxalate content in water samples.

Full text of DOI:10.1002/cjoc.201090198

FULL PAPER
Highly Selective Potentiometric Oxalate Ion Sensors Based on
Ni(II) Bis-(m-aminoacetophenone)ethylenediamine
,b
Rawat, Arunaa,b
Chandra, Sulekh
Sarkar, Anjanaa
*
a School of Applied Sciences, Netaji Subhas Institute of Technology, University of Delhi, Azad Hind Fauj Marg,
Sector-3, Dwarka, New Delhi 110078, India
b Department of Chemistry, Zakir Husain College, University of Delhi, J.L.Nehru Marg, New Delhi 110002, India
A plasticized PVC (polyvinyl chloride) membrane based oxalate ion selective electrode has been developed by
using the condensation product of m-aminoacetophenone and ethylenediamine. The transition metal complexes of
the ligand N,N'-bis(m-aminoacetophenene)ethylenediamine (L) were synthesized and incorporated as ionophore for
the synthesis of oxalate ion selective electrodes. Most appropriate result in terms of dynamic range, detection limit
and response behavior was determined for the Ni(II) bis-(m-aminoacetophenone)ethylenediamine complex. The
electrode demonstrated higher selectivity for oxalate ion with improved performance as compared to other carriers
reported in past. The electrode shows Nernstian slope of (－28.5±0.4) mV•decade－ 1 with improved linear range of
－
－
1×10－ —1×10 mol•L 1, with a comparatively lower detection limit in the pH range of 5—10.5, giving a rela-
tively fast response within 10 s and reasonable reproducibility. The selectivity coefficient was calculated using
matched potential method and fixed interference method. The lifetime of the electrode was found to be nearly 2
months. The response mechanism and the interaction of oxalate ion with the complexes have been discussed by
UV-visible spectroscopic technique. Further the electrode was also successfully applied to determine the oxalate
content in water samples.
1
7
Keywords oxalate ion, ion selective electrodes, potentiometry
Introduction
anti-Hofmeister selectivity sequence.7-9 Thus the re-
search on anti-Hofmeister sensing materials for anion as
well as developments including new synthetic ionopho-
res, new reference electrodes, miniaturization of the
detecting device etc. makes it an ever-expanding culture
for research in chemical sensors.
Most of the analytical methods like ion chromatog-
raphy,1 neutron activation analysis, atomic absorption
spectrophotometry2 and mass spectrometry3 etc. have
been reported for the determination of ions at a very low
concentration levels, but these methods require expen-
sive instrumentation, delicate and expert handling of the
sample and instrument. Hence potentiometric determi-
nation based on ion selective electrodes offer several
advantages such as ease of preparation, low cost, simple
procedure and easy instrumentation. It gives relatively
fast response, wide linear range, good selectivity, high
detection limit and online applications as compared to
other analytical methods.4 These can also be used in
complex and coloured media. Therefore, there has been
progressive growth in the development and application
of potentiometric sensors based on polymeric membrane
ion selective electrodes incorporating ionophores for the
detection of different cations and anions and other bio-
logically important compounds.5
Oxalate determination is useful for detection of in-
soluble salts and stones that deposit in the renal tissues
in human being.10 Oxalate ion also inhibits the calcium
adsorption in the body. It is one of the important nutri-
ents found in food stuffs like guava, spinach etc. The
designed electrode can be applied to determine oxalate
ion in real samples. Oxalate is a common constituent of
most diets and a byproduct of metabolism, and if it is
not sufficiently degraded, it may accumulate in the body.
It plays a crucial role in the formation of most renal
stones.11 In the body oxalates can be found as two forms
in vivo: oxalate ions and calcium oxalate monohydrate
(COM) crystals that readily form in the presence of cal-
cium. Numerous studies were used to characterize the
cytotoxicity of oxalate as including plasma membrane
damage and organelle injury. The factors affecting the
urinary excretion of oxalate are critical to the risk of
forming calcium oxalate stones.
Recent studies in different laboratories showed in-
corporation of different novel materials as ionophores
for the ion selective electrodes.6 A strong interaction of
the anions and the ionophore as well as the steric effect
associated with the structure of the ligand gives rise to
In the present studies of potentiometric sensor for
oxalate ion has been prepared with improved response
*
E-mail: schandra_00@yahoo.com; arunarawat_ar@yahoo.co.in
Received April 4, 2009; revised May 15, 2009; accepted February 23, 2010.
1140
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Chin. J. Chem. 2010, 28, 1140— 1146

Highly Selective Potentiometric Oxalate Ion Sensors
characteristics based on Ni(II) bis-(m-aminoacetophe-
none)ethylenediamine (NiL). The electrode was inves-
tigated for the study of selectivity and sensitivity to ox-
alate ion in the presence of the various other ions. The
electrode was used for different aspects of ion selective
electrode study. An oxalate sensor showed improved
workable pH range, fast response time and reasonable
reproducibility as compared to previously reported ox-
alate selective electrodes.12-14
analysis, IR (Figure 2) and UV-visible spectra. The
complex Ni(II) bis-(m-aminoacetophenone)ethylenedia-
mine (NiL) showed the best response as compared to
other transition metal complexes of L as an oxalate se-
lective electrode; hence it was used for further studies.
Experimental
Reagents and apparatus
Figure 1 (a) Structure of the ligand L and (b) structure of the
Reagent grade DBP (di-butyl phthalate), DOP
(di-octyl phthalate), o-NPOE (o-nitrophenyl octylether)
were purchased from Merck. High molecular weight
PVC powder, THF and cation excluder MTOAC
(methyl trioctylammonium chloride) and metal salts
were procured from Sigma-Aldrich. All the reagents
were of highest pure grade and used without further pu-
rification. Standard solutions were freshly prepared in
deionized water.
The complexes used in the electrode preparation
were synthesized in the laboratory and then were char-
acterized. The C, H, N were analyzed on a Carlo-Erba
1106 elemental analyzer. IR spectra (KBr) were re-
corded on a Perkin Elmer FTIR spectrum BX-II spec-
trophotometer. Electron impact mass spectrum was re-
corded on Joel-MS Route mass spectrometer. NMR
spectra were recorded on BBO_proton DPX-300 spec-
trometer and the electronic spectra were recorded on
Shimadzu UV mini-1240 spectrophotometer.
complex NiL.
Electrode preparation
The membranes for ion selective electrodes were
prepared according to Thomas and co-worker.15 An ox-
alate selective electrode was prepared by dissolving the
mixture of fixed amount of ionophore, PVC powder,
plasticizer and cation excluder in the w ratio of 4%
ionophore (complexes), 31% PVC, 64% o-NPOE and
1% MTOAC in 5 mL of THF. The mixture was kept at
room temperature for the solvent to evaporate slowly so
as to obtain a thin membrane. The membrane was then
cut and pasted to one end of Pyrex glass tube. The tube
was then filled with internal filling and external solution
of potassium oxalate for preconditioning for 24 h before
use.
Potentiometric study of the electrode were carried
out by the following cell assembly: Hg-Hg2Cl2 KCl
(saturated)|internal solution 1.0×10－ 2 mol•L－ 1 K2C2O4/
PVC membrane|test solution|Hg2Cl2-Hg, KCl (satu-
rated).
Potential differences between the ion selective elec-
trodes and the double junction calomel electrodes were
measured with Systronics type 335 digital pH, mV me-
ter at room temperature.
Synthesis of ionophore
Bis-(m-aminoacetophenone)ethylenediamine ligand
(L) was synthesized by mixing an ethanolic solution of
m-aminoacetophenone (0.02 mol) and ethylendiamine
(0.01 mol). The mixture was refluxed for 3 h. On cool-
ing the reaction mixture a yellow coloured precipitate
was obtained. The precipitate was then filtered, washed
and recrystallized from methanol. Yield 85%, m.p. 120
℃; MS m/z: 295 (100); 1H NMR (DMSO, 300 MHz) δ:
7.1 (s, 6H), 6.8 (d, 2H), 5.3 (s, 2H), 2.5 (s, 1H); IR (KBr)
Several membranes incorporating NiL as carrier was
made to study the behavior of best optimized membrane
and the one which generated the best potentiometric
response was further studied in detail for selectivity, pH
range, and the determination of oxalate ion in the water
samples.
－
1
ν: 3385, 3363, 3279, 1632, 1551 cm . Anal. calcd for
C18H22N4: C 73.47, H 7.48, N 19.04; found C 73.56, H
7.53, N 19.12.
Results and discussion
Synthesis of complex of ligand (l)
Ni(NO3)2•3H2O (0.001 mol) was dissolved in etha-
nol. To this solution hot ethanolic solution of L (0.002
mol) was added. The reaction mixture was refluxed for
12 h at 80 ℃. On cooling green coloured precipitate
was obtained. It was filtered and crystallized. Yield 68%,
m.p. 235 ℃; IR (KBr) ν: 3351, 3369, 1605, 1366, 1148
Optimization of the membrane
The selection of a suitable carrier is the most impor-
tant phenomena in recognition mechanism of the ana-
lyte ion, but some other aspects such as use of mem-
brane additive, plasticizers16,17 and polymer matrix must
not be ignored. The sensitivity, linearity and selectivity
for a given ionophore depend significantly on the mem-
brane composition, nature and the amount of additives
used with respect to the taken ionophore.18 This oxalate
－
1
cm . Anal. calcd for C18H22N4Ni: C 61.24, H 6.23, N
15.87; found C 61.31, H 6.01, N 15.92.
Figure 1 shows the structure of the complex formed
which was characterized and confirmed by elemental
Chin. J. Chem. 2010, 28, 1140— 1146
© 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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1141

Rawat, Chandra & Sarkar
FULL PAPER
Figure 2 IR spectra of the m-aminoacetophenone, ethylenediamine, ligand and the complex.
Response characteristics
selective electrode worked well as plasticizer/PVC ratio
nearly 2∶1 (w/w) corresponding to the maximum sen-
sitivity of the electrode.19 The ionophore/additive ratio
of 4∶1 was most optimized for the response character-
istics of the electrode; this ratio corresponds to the
changes in selectivity values and Nernstian response of
the electrode.20 Best membrane response was recorded
for S.No. 7 in the Table 1 which comprises of PVC 32%,
o-NPOE 63%, ionophore 4% and MTOAC 1% (w)
which gave the reasonable response characteristics.
After the calibration of the electrodes, the electrode
generated the stable potential response for oxalate ion.
The role of internal filling solution concentrations was
studied on the potential response of the sensor,21 which
is correlated to the detection limit of the proposed ox-
alate sensor. The plot in Figure 3 indicates that the best
response was obtained for the oxalate ion. The calibra-
tion curve slope was found to be (－28.5±0.4) mV•
Table 1 Optimization and different composition of membranes (w/%)
－1
S.No.
PVC
33
33
32
32
32
32
32
32
32
32
Plasticizer
Ionophore
Excluder (MTOAC)
Response time/s
Slope/(mV•decade
)
1
2
3
4
5
6
7a
8
9
67 (DOP)
4
4
0
1
2
3
4
5
4
6
0
1
0
1
1
1
1
1
2
2
20
－12.5
65 (DOP)
22
－20.7
68 (o-NPOE)
66 (o-NPOE)
65 (o-NPOE)
64 (o-NPOE)
63 (o-NPOE)
62 (o-NPOE)
62 (o-NPOE)
60 (o-NPOE)
＞30
20—25
10
－18.6
－19.4
－22.3
20
－19.1
5—10
18—25
25
－28.5
－20.3
－23.4
10
20
－18.3
a Most optimized membrane composition.
1142
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© 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2010, 28, 1140— 1146

Highly Selective Potentiometric Oxalate Ion Sensors
to investigate such mechanism UV-visible spectra of
carriers without and with C2O24－ were recorded. A
UV-visible spectrum of NiL of 1×10－
mol•L－
2
1
concentration dissolved in DMSO was recorded first. It
was then used for the quantitative complexation with
oxalate ion by adding increasing amount of the oxalate
ion upto 1×10－ 2 mol•L－ 1 concentration. The spectra of
the complex NiL as carrier [C] show the absorption
bands at 362 and 448 nm in Figure 4(a). In Figure 4(b)
shift in the peaks was observed and the new peaks were
observed at 353 and 441 nm with increased absorptivity,
when oxalate ion interacted with the carrier, which
shows that the size of the complex increases on interac-
tion of oxalate with the carrier. The absorption intensity
changes as a function of [ C2O24－ ]/[C] molar ratio.23
Effect of pH
Figure 3 Potentiometric response curve for different ions.
The effect of pH on electrode potential was deter-
mined at various concentration of oxalate ion by adding
－
7
decade－ in the linear range of 1×10－ —1×10
1
1
mol•L－ oxalate ion concentration with the detection
1
dilute H2SO4 or NaOH. In Figure 5, pH range was de-
limit of 4.5×10－ mol•L . The overall optimized
membrane potentiometric response characteristics have
been summarized in Table 2 and the comparative results
of different oxalate selective electrodes12-14 have been
recorded in Table 3.
－
7
1 22
－
tected from 2—12 at 1×10－ mol•L oxalate ion con-
centration. The optimum range determined for the elec-
trode is 5—10.5. In the low pH range (below 5), sharp
change in the potential may be due to the oxalate ion
2
1
－
(OX2 ) getting converted to (HOX－ ) or oxalic acid.
The selectivity of the resulting sensor is character-
ized by the lipophilicity of the analyte ion relative to the
interfering ion, and the relative strength of the complex
formed in the membrane. The interaction mechanism of
oxalate ion with the ionophore was discussed on the
basis of UV-Visible spectrophotometry. Thus, in order
According to the Ka (oxalic acid) the minimum pH at which
oxalate can exist is nearly 5, whereas in high pH range
i.e., above 10.5 it shows that OH－ ion competes and
interferes with the oxalate ion activity.
Table 2 Characteristics of the oxalate ion selective electrodes
Properties of the sensor
Type of electrode
Values
Plasticized PVC membrane electrodes
PVC∶Plasticizer∶Ionophore∶Excluder
32∶63∶4∶1
Optimum composition w/%
Conditioning time and concentration
Polymeric PVC membrane electrode
－1
－1
－7
Linear working range/(mol•L
)
1×10 —1×10
Slope and standard deviation/mV
－28.5, ±0.4
5—10.5
pH
－1
－7
Detection limit/(mol•L
Lifetime/d
)
4.5×10
60
Response time/s
Storage
5—10
Buffer pH 5.2 with K2C2O4
Table 3 Comparative results of the previously reported oxalate selective electrodes
－
－
－1
Electrode
Nernstian slope (mV•Decade ) Detection limit/(mol•L 1) Linear range/(mol•L 1)Response time/spH rangeLifetime/d
－7
－7
－1
Proposed electrode
－28.5±0.4
4.5×10
1.0×10 —1.0×10
5—10
5—10.5
60
－8
－8
－1
Ref 12
－29.2±0.6
－25.6±0.1
－23.6±0.1
－28.7±1.0
5.0×10
1.0×10
1.0×10
6.3×10
5.0×10 —1.0×10
10—15
2.0—7.0
2.0—8.0
2.0—7.0
—
－9
－9
－8
－4
－4
Ionophore (Ia)13
Ionophore (Ib)13
Ref. 14
1.0×10 —1.0×10
—
—
－7
1.0×10 —1.0×10
－7
－6
－1
1.0×10 —1.0×10
5—15
2.0—7.8 ＞60
＋
＋
Ia and Ib are [Fe(o-phenanthroline)3]2 and [Fe(neocuproin)3]2
.
Chin. J. Chem. 2010, 28, 1140— 1146
© 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
1143

Rawat, Chandra & Sarkar
FULL PAPER
－
－2
－2
Figure 4 UV-Visible interaction mechanism of (a) NiL (1×10 mol•L 1) in DMSO and (b) NiL complex with oxalate ion (1×10
－1
mol•L ) in DMSO.
Figure 5 Effect of pH on the potentiometric response of oxalate
selective electrode.
Figure 6 Dynamic response time and reversibility of the ox-
alate selective electrode.
Dynamic response time, reversibility and reproduci-
bility
According to the IUPAC recommendation, the re-
sponse time is defined as the time which elapses be-
tween the instant at which an ion selective electrode and
the reference electrode are brought into contact with the
sample solution (or at which the activity of the analyte
ion in a solution is changed) and the first instant at
which the emf/time ∆E/∆t slope becomes equal to the
limiting value on the basis of experimental conditions.
Thus the practical response time was measured for the
sensor after successive immersion of a series of oxalate
ion solutions, each having ten-fold difference in con-
centration so as to reach a potential within ±1 mV of
the final equilibrium value as shown in Figure 5. Re-
sponse time is critically reviewed when it comes to
analytical application of the sensor.24 It is governed by
the transport diffusion processes in the aqueous diffu-
sion layer. The response behavior and reversibility was
checked by step change in concentration25 and simulta-
neous recording of the potentiometric response of the
electrodes. Figure 6 shows the dynamic response curve
for the oxalate ion selective electrode.
The reproducibility and stability of the electrode was
checked by repeated recording of potential and calibra-
tion over a period of 2 months. The results showed
slight decrease in slope and detection limit. Hence Table
4 shows that the lifetime of the sensor is nearly 2 month
after which the potentiometric response seems to be
deteriorating. The lifetime of the sensor is limited by the
two factors: Leaching of the ionophore from the mem-
brane phase to the sample as a result of low partition
coefficient at sample/membrane interface; and the ex-
traction of plasticizer by the sample which indicates the
non-uniformity of the membrane and hence delayed or
poor potentiometric response of the sensor/or degrada-
tion of mobile ionic site additives of the membrane
phase, which may catalyze ion transfer.26,27
Selectivity
The most important characteristic of any ISEs is its
relative response to primary ion over other ions present
1144
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Chin. J. Chem. 2010, 28, 1140— 1146

Highly Selective Potentiometric Oxalate Ion Sensors
Table 4 Lifetime and stability of oxalate selective electrode
based on NiL for 2 month
Table 5 Potentiometric selectivity coefficient values for various
interfering anionsa
－1
－1
Time/Week Slope/(mV•decade
)
Detection limit/(mol•L
)
Anion
lg Ksel
－2.7
－3.1
－3.3
－4.0
－4.2
－4.2
－4.8
－5.0
－5.3
－5.6
－3.1
lg Ksel'
－1.3
－2.8
－2.2
－1.9
－1.1
－3.8
－2.5
－4.3
－3.8
－4.8
－2.5
－7
－
1
2
3
4
5
6
7
8
9
－28.5
－28.4
－28.3
－27.8
－27.4
－27.4
－27.1
－27.8
－26.0
4.5×10
ClO4
－7
4.3×10
CO32－
CH3COO－
CrO24－
－7
4.0×10
－7
3.8×10
－7
3.7×10
SO24－
－7
－
3.7×10
NO3
－7
2.4×10
SCN－
I－
Br－
－7
1.3×10
－6
8.2×10
－
NO2
PO34－
in the solution which is expressed in terms of potenti-
ometric selectivity coefficient, K
28,29
A,B
pot
,
which de-
a Ksel are the values using MPM and Ksel' are the values using
scribes the preference of the membrane for an interfer-
ing ion as compared to oxalate ion. The selectivity coef-
ficient values were calculated by Matched Potential
Method (MPM) and Fixed Interference Method (FIM).30
According to the former method, when the activity of
primary ion aA increases to aA', the change in potential
is measured. Then the interfering ion is added of activity
aB, to primary ion solution of activity aA and the same
change in potential is measured, hence the values were
calculated using the following equation.
FIM.
compared to the previously reported work. The im-
proved pH range for the electrode was 5—10.5. The
sensor was used for the direct determination of oxalate
in the given water samples with reproducible results.
Analytical application
Oxalate ion sensor can be applied for the determina-
tion of oxalates in the several real samples and water
samples. The proposed sensor was used to monitor ox-
alate ion concentration in water samples using standard
addition method, where known concentration of oxalate
ion are added and recovered using the electrode. The
results are summarized in Table 6.
A
A
B
A,B
pot
K
＝(a '－a )/a
(1)
where aA is the activity of primary ion and aA' is the
activity of A in presence of interfering ion B.
In FIM, the potential of the cell is measured for a
number of solutions containing interfering ion of con-
stant activity aY but varying values of activity of pri-
mary ion aX. The value of selectivity coefficient is then
calculated using the following equation.
Table 6 Determination of oxalate ion in the water samples us-
ing proposed sensor
Added oxalate ion Found oxalate ion
No.
Recovery/%
－1
－1
conc./(mol•L
)
conc./(mol•L )
－4
－4
1
2
3
1.50×10
1.35×10
2.65×10
1.41×10
1.26×10
2.48×10
94.00
93.33
93.58
X,Y
pot
X /ZY
K
＝aX / (aY )Z
(2)
－5
－6
－5
－6
where aX is the activity of primary ion and aY is the ac-
tivity of interfering ion Y. ZX and ZY is the charge on
primary and interfering ion. The interference of differ-
ent ions on the basis of MPM and FIM can be seen in
Table 5.
Acknowledgement
The author is thankful to the principal, Zakir Husain
College for providing the laboratory facility and Netaji
Subhas Institute of Technology for financial assistance.
Conclusion
The potentiometric properties towards sensing of
oxalate ion are dependent upon the ionophore, plasti-
cizer and additive used in the preparation of the elec-
trode. The membrane exhibits a linear stable response
over a wide concentration range with a near Nernstian
response of －28.5 mV/decade. Selectivity coefficient
values were calculated using MPM. The membrane was
found to be stable and recorded steady potential values
within 5—10 s with satisfactory reproducibility as
References
1
Chen, Y.; Li, Q.; Yang, Z.; Zhang, F. Chin. J. Chromatogr.
1989, 7, 226.
2
3
Zhang, Z. Q.; Xu, X. Q. Anal. Chim. Acta 2000, 406, 303.
Perez-riaz, T.; Martinez, C.; San, A.; Val, V. Anal. Chim.
Acta 1993, 284, 173.
4
Jakmunee, J.; Grudpan, K. J. Anal. Chim. Acta 2001, 430,
299.
Chin. J. Chem. 2010, 28, 1140— 1146
© 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
1145

Rawat, Chandra & Sarkar
FULL PAPER
5
Buhlmann, P.; Pretsch, E.; Bakker, E. Chem. Rev. 1998, 98,
1593.
18 Bakker, E.; Buhlmann, P.; Pretsch, E. Chem. Rev. 1997, 97,
3083.
6
7
8
Kharitonov, S. V. Russ. Chem. Rev. 2007, 4, 361.
Hofmeister, F. Arch. Exp. Patol. Pharmakol. 1988, 24, 247.
Wuthier, U.; Pham, H. V.; Zund, R.; Welti, D.; Funck, R. J.
J.; Bazegh, A.; Ammann, D.; Pretsch, E.; Simon, V. Anal.
Chem. 1984, 56, 535.
19 Mazloum, M.; Ensafi, A. A.; Salavati, M.; Mirhoseimi, S.
Anal. Chim. Acta 2002, 462, 25.
20 Huser, M.; Gehrig, P. M.; Morf, W. E.; Simon, W.; Lindner,
C.; Jeney, J.; Toth, K.; Pungor, E. Anal. Chem. 1991, 63,
1380.
9
Zare, H. R.; Memarzadeh, F.; Gorji, A.; Ardakani, M. M. J.
Braz. Chem. Soc. 2005, 16, 571.
21 Shamsipur, M.; Soleymanpour, A.; Akhond, M.; Sharghi, H.;
Hasaninejad, A. R. Sens. Actuators B 2003, 89, 9.
22 Bakker, E.; Pretsch, E. Trends Anal. Chem. 2005, 24, 119.
23 Amini, M. K.; Ghaedi, M.; Rafi, A.; Habibi, M. A.; Zohory,
M. M. Sensors 2003, 3, 509.
24 Macca, C. Anal. Chim. Acta 2004, 512, 183.
25 Ganzali, M. R.; Norouzi, P.; Ghani, M.; Salavati-Niasari, M.
Anal. Chim. Acta 2006, 567, 196.
26 Mathison, S.; Bakker, E. Anal. Chem. 1989, 70, 303.
27 Bakker, E.; Buhlmann, P.; Pretsch, E. Chem. Rev. 1997, 97,
3083.
28 Umezawa, Y.; Buhlmann, P.; Umezawa, K.; Tohda, K.;
Amemiya, S. Pure Appl. Chem. 2000, 72, 1851.
29 Umezawa, Y.; Umezawa, K.; Sato, H. Pure Appl. Chem.
1995, 67, 507.
10 Hisamato, H.; Siswanta, D.; Nishihara, H.; Suzuki, K. Anal.
Chim. Acta 1995, 304, 171.
11 Baumann, J. M.; Affolter, B.; Siegrist, H. P. Scanning Mi-
croscopy 1999, 13, 291.
12 Ardakani, M. M.; Jalayer, M.; Naeimi, H.; Heidarnezhad, A.;
Zare, H. A. Biosens. Bioeletr. 2006, 21, 1156.
13 Stefan, R. I.; Draghici, I.; Baiulescu, G. E. Sens. Actuators B
2000, 65, 250.
14 Ardakani, M. M.; Iranpoor, F.; Karimi, M. A.;
Salavati-Niasari, M. Bull. Korean Chem. Soc. 2008, 29, 398.
15 Craggs, A.; Moody, G. J.; Thomas, J. R. D. J. Chem. Edu.
1974, 51, 541.
16 Maria De Los, A.; Perez, A.; Marin, L. P.; Quintana, J. C.;
Yazdani-Pedram, M. Sens. Actuators B 2003, 89, 262.
17 Sadeghi, S.; Faithi, F.; Esmaeili, A. A.; Naeimi, S. Sens.
Actuators B 2006, 114, 928.
30 Umezawa, Y. CRC Hand Book of Ion-Selective Electrodes
Selectivity Coefficients, CRC Press, Boca Raton, Ann Arbor,
Boston, 1990.
(E0904041 Sun, H.; Fan, Y.)
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