Research Article Open Access
Volume 4 • Issue 1 • 1000127
J Membra Sci Technol
ISSN:2155-9589 JMST an open access journal
Open Access
Research Article
Kassem et al., J Membra Sci Technol 2014, 4:1
DOI: 10.4172/2155-9589.1000127
*Corresponding author: AT Kassem, Hot Labs. Center, Atomic Energy Authority,
P.C. 13759, Cairo, Egypt, Tel: 202 0106369977; E-mail: nessemsalam@gmail.com
Received February 05, 2014; Accepted February 18, 2014; Published February
25, 2014
Citation: Kassem AT, El Said N, Aly HF (2014) New Ion Selective Sensitive
Electrode of Pd (II) as Multisensor Based on IRA-410 via Low Cost Oxidation
Reduction Process. J Membra Sci Technol 4: 127. doi:10.4172/2155-9589.1000127
Copyright: © 2014 Kassem AT, et al. This is an open-access article distributed
under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited.
New Ion Selective Sensitive Electrode of Pd (II) as Multisensor Based on
IRA-410 via Low Cost Oxidation Reduction Process
AT Kassem*, N El Said, and HF Aly
Hot Labs. Center, Atomic Energy Authority, P.C. 13759, Cairo, Egypt
the formic acid concentration till 50% followed by dissolving the
separated palladium by nitric acid. Selective ecient method is used
for separation of palladium [4-12] by strongly basic anion exchangers
IRA-410 and IRA-900 from intermediate radioactive nitrate medium
dierent conditions for exchange behaviour of palladium from (ILLYO
solutions containing number of elements were investigated by batch
technique. Selective recovery of palladium from (ILLW) solution was
achieved using column technique the elution [13] of palladium was
carried out via reduction with formic acid. Ion-selective electrode
based potentiometry has become a well-established electro-analytical
technique. In this technique the most exciting and fastest growing
area of research is the use of ion sensitive membrane electrodes for
analysis of wastewater containing heavy metals. Using this approach the
applicability of the potentiometric method has been greatly extended
[14-17] enabling the simple and accurate determinations of many
heavy metal ions and has led to a search for suitable materials that can
be used for preparation of sensitive and selective ion-sensors, chemical
sensors or more commonly ion-selective electrodes ((ISEs) [18,19]. Ion
selective electrode based on palladium (II) dichloride acetylthiophene
fenchone azine (I) has been developed.
Experiment
Reagents and chemicals
e strongly basic anion exchanger was used as previously described
[4]. e plasticizers were obtained from Aldrich (Milwaukee, WI).
While poly vinyl chloride powder (PVC) were obtained from Fluka
(Buchs, Switzerland). e chloride salts of all cations studied (Figure 1).
XRD and SEM characterization of Amberlite-410
As it is shown in Figures 2, 3a and 3b, Pd (II) was chosen as the
Abstract
A novel ion selective IRA-410 membrane disc sensor for Pd (II) ions has been prepared and studied. This
electrode has a wide linear dynamic range from 10
-1
to 2.5×10
-6
mol
-1
with a Nernstian slope of 16.5 ± 0.2 mV
decade
-1
and low detection limit of 1.6×10
-6
mol l
-1
. It has a fast response time (<1 s) and good selectivity with respect
to different metal ions. IRA-410 based electrode was suitable for aqueous solutions of pH range from (1.0- 9.0). It
can be used for about 10 months with complex with Pd (II) was calculated by using segmented sandwich membrane
method. The formation constant of ionophore of IRA-410 and its Pd (II)-Complex is examined using Fourier-transform
infrared analysis and elemental analysis techniques. The proposed electrode has been used successfully as an
indicator electrode in potentiometric determination in aqueous nitrate and /or chloride media.
Keywords: Membrane sensor; Nernstian slope; IRA-410 based
electrode; Ionophore complex; Aqueous and nitrate media.
Introduction
Separation of palladium by strongly basic anion exchangers IRA-410
and IRA-900 from intermediate radioactive liquid waste in chloroacetic
acid/nitrate medium containing thirteen elements have been achieved.
Dierent conditions have been studied, the eect of NaNO
3
as salt
content, chloroacetic acid and hydrogen ion concentration have been
investigated. Selective recovery of palladium from the [ILLW] solution
was achieved using the column technique. e selectivity increased
by using chloroacetic acid/nitrate than in nitrate medium. e elution
of palladium was carried out via reduction with formic acid [1-3]
where the rate of the reduction process was increased by decreasing
CH
3
CH
3
CH
3
N
+
Cl
-
Figure 1: Structure: Amberlite IRA- 410 in chloride medium.
0 5 10 15 20 25 30 35 40 45 50
IRA-410
Intensity
2θ
Figure 2: XRD Pattern for PVC on pd after.
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ISSN: 2155-9589
Citation: Kassem AT, El Said N, Aly HF (2014) New Ion Selective Sensitive Electrode of Pd (II) as Multisensor Based on IRA-410 via Low Cost
Oxidation Reduction Process. J Membra Sci Technol 4: 127. doi:10.4172/2155-9589.1000127
Page 2 of 7
Volume 4 • Issue 1 • 1000127
J Membra Sci Technol
ISSN:2155-9589 JMST an open access journal
appropriate sorbent for the sorption of Amberlite-410 among all
the sorbents tested in this work. X-ray powder diraction (XRD)
characterization showed that the natural samples of Amberlite-410,
Figure 2: XRD pattern of acid-treated. Amberlite-410 with 2MHCl
almost pure. Elemental content of the mineral was revealed using energy
dispersive X-ray spectroscopy (EAR). e percentages of the elements
are given in Table 1. e values given correspond to an average of Data
points selected randomly on the surface of Amberlite-410. A scanning
electron microscope (SEM) micro image is provided in Figures 2, 3a
and 3b. is Figures show typical Amberlite-410 crystals with sizes
varying up to several µm.
Powder XRD pattern of Pd nanoparticles is shown in Figure 2. e
d-spacing corresponding to XRD lines is 2.236, A
°
. ese d-spacing
values correspond to (111), (planes with lattice constant, a = 3.871
A
°
. is observation conrms the presence of metallic Pd with fcc
structure. XRD line corresponding to {111} plane is found to be
unusually intense. SEM images of black particles are shown in Figure
3a and 3b. Aggregates of irregular-shaped particles are observed and
the size of Pd particles varies from 8 to 25 nm. Of particles are formed
due to the self-assembling nature of palladium tetra chloroacmplox on
IRA-410. is self-assembly of the particles also conrms the capping
ability of Pd on IRA-410.
Apparatus: Potentiometeric measurements were performed at 25 ±
1
°
C using a Fisher scientic-computer aided pH/ milivoltmeter (Model
450) with a palladium PVC matrix membrane electrodes in conjunction
with a double junction Hg|HgCl
2
|KCl (satd.) reference electrode (Cole-
Parmer Co., Chicago, Illinois 60648). A Fisher Accumet Model 825 MP
pH-meter (accuracy ± 0.00 1 pH) with a glass pH electrode (Fisher
electrode no. 13-639-90) was used for all pH measurements). Figure 4:
using the KBr technique was used for infrared measurements. (Figure
3a,b) (Figure 4) (Table 2).
Calibration Curve: Figure 5: ese sensors exhibit the maximum
working concentration range of 1.0×10
-7
to 1.0×10
-3
M with a slope of >16
mVdecade-1 of activity (Sensor of Pd (II) ion selective electrode). e
PVC-membranes were prepared and aggregation into sensor electrodes
using established procedures [20-24]. e prepared membranes
contained 1.2 mg ionophore (IRA-410), 0.60 mg lipophilic salt, 60 mg
PVC and 10 mg membrane solvent were mixed with 0.5 ml (THF) I
mixed together very well and making compact disk with diameter 0.5
cm and thickness 0.2 cm and drying. In the glass dish with an diameter
of 30 mm resting on a smooth mould. THF tetrahydrofuran was allowed
to evaporate for 48 h standing at room temperature. Transparent PVC
membranes were obtained with a thickness of 0.2 mm. A 11 mm
diameter piece was cut out from the PVC membrane and attached to
a PVC tube by means of PVC–THF solution Figure 6: wavelength(nm)
3a 3b
Figure 3: The SEM for PVC and Pd(II) (before).
Resin C% N% O% Cl%
IRA-410 85 12 2.33 0.67
Table 1: Elemental analysis results after addition the IRA-410.
Indicator
electrode
Sensitive
Salt
bridg
Reference
Figure 4: Experimental set- up for potentiometry.
Membrane PVC
Composition %
Plasticizer
NBPP Additive
Slope/mV
decade
-1
)
1 60 2,NaTFPB --------- 2,KTClPB 12.5 ± 0.2 mV
2 60 2,NaTFPB --------- 2,KTClPB 28.4 ± 0.2 mV
3 60 2,NaTFPB 0.8 4,KTClPB 14.6 ± 0.2 mV
4 60 4,NaTFPB 1.2 4,KTClPB 9.8 ± 0.2 mV
5 60 2,NaTFPB 1.6 3,KTClPB 12.4 ± 0.2 mV
Table 2: Optimization of membrane ingredients.
0 2 4 6 8 10 12
0
20
40
60
80
100
Y=64.47739...r=70.82151
X=4.34412 S=16.5
E(m/V)
-logC
Fig(5):Calibration Curve
Figure 5: Calibration Curve.
0 20 40 60 80 100
1370
1372
1374
1376
1378
1380
wave length(nm)
Conc. THF in PVC (w/w)
Figure 6: Wavelength (nm) up on solvent (pvc) in aqueous solution.
Citation: Kassem AT, El Said N, Aly HF (2014) New Ion Selective Sensitive Electrode of Pd (II) as Multisensor Based on IRA-410 via Low Cost
Oxidation Reduction Process. J Membra Sci Technol 4: 127. doi:10.4172/2155-9589.1000127
Page 3 of 7
Volume 4 • Issue 1 • 1000127
J Membra Sci Technol
ISSN:2155-9589 JMST an open access journal
long-term response to senstivity this led to the use of sensors for a long
period of more than 6 months and under the continued use of this
investigation.
Results and discussion
Dynamic response time
Dynamic response time of the Pd (II) sensor: e determination
of palladium (II) by potentiometric titration based on the formation of
a water-insoluble ion pairs of PdX4
2−
and PdX
3−
complexes (X = Cl
−
, Br
−
,
I
−
, CN
−
, SCN
−
) [29] with a cationic titrant such as alkyl ammonium [30-
32], alkylphosphonium [33-35] and crystal violet [36] were published.
An important requirement for preparation of an ion selective sensor
is that membrane electroactive material should have high lipophilicity
and strong anity for a target metal ion and poor anity to the others.
It is well known that coordination abilities of ligands containing
sulfur atom, are very selective to the transition metal ions. However,
most of these show some limitations in their working activity range,
selectivity, response time, pH range and lifetime. us, the development
of reliable sensing ion selective sensors for palladium ion is considerable
importance for environment and human health. To improve the
analytical selectivity, it is essential to search novel carrier compounds
that would interact with palladium ion with high selectivity. Because
of the ligand that contain sulphur highly selective for Pd (II), classied
as a “so” Lewis acid. e use of IRA-410 as an ionophore is reported
in the construction of a Palladium (II)-PVC membrane electrode and
their characteristic and properties of selective electrode were studied.
e novelty comes from that it can be used in aqueous and solid phases.
e washing was used by elution of palladium absorbed palladium
via reduction of palladium by formic acid. It is used for reducing of
palladium producing palladium metal and sensing it in metallic
palladium. e reduced palladium can be used as sensor hydrogen.
Time response, when total solution eect of the time according the
equation (1)
0
() { ( ) }
t
e
y t Kt K t T
−
τ
=+−
(1)
Where Kt represent yp (t)…… K(t
0
-T)
e
-t/r
yH(t)
e rst term from equation describe the particular solution the
end term is homogeneous solution. e dynamic response time of the
Pd (II) (ISE)s selective electrode , of the most important factors .study
upon solvent(PVC)in aqueous solution as previously described [25].
e PVC tube with the membrane was then incorporated into an
Hg|HgCl
2
|KCl inner electrode (1.0 mm diameter). e dried tube was
lled with internal solution contained 10
-3
moll
-1
pdCl
2
and 10
-3
mol l
-1
KCl. en, the electrode was conditioned for 1 h in 10
-3
mol l
-1
pdCl
2
solution [26].
Preparation of PVC–membrane: e PVC-membranes were
prepared and aggregation into sensor electrodes using established
procedures (20-24). e prepared membranes contained 1.2 mg
ionophore (IRA-410), 0.60 mg lipophilic salt, 60 mg PVC and 10 mg
membrane solvent were mixed with 0.5 ml (THF) I mixed together very
well and making compact disk with diameter 0.5 cm and thickness 0.2
cm and drying. In the glass dish with a diameter of 30mm resting on
a smooth mould. THF tetrahydrofuran was allowed to evaporate for
48 h standing at room temperature. Transparent PVC membranes were
obtained with a thickness of 0.2 mm. A 11 mm diameter piece was cut
out from the PVC membrane and attached to a PVC tube by means of
PVC–THF solution as previously described (25). e PVC tube with
the membrane was then incorporated into an Hg|HgCl
2
|KCl inner
electrode (1.0 mm diameter). e dried tube was lled with internal
solution contained 10
-3
moll
-1
pdCl
2
and 10
-3
mol l
-1
KCl. en, the
electrode was conditioned for 1 h in 10
-3
mol l
-1
pdCl
2
solution [26].
Potential measurement: All potential measurements were
performed at 25 ± 1
°
C using a Fisher scientic-computer aided pH/
milivoltmeter (Model 450). e electrochemical system for this
electrode can. e performance of the electrode was investigated by
measuring its potential in palladium chloride solutions prepared in the
concentration range (10
-1
to 10
-7
) mol l
-1
by gradual dilution of stock
standard solution 0.1 mol l
-1
of pdCl
2
, with triply distilled water. e
potentiometric selectivity coecients (log K Pot Pd, B) were measured
using the separation solution method (SSM) and the mixed solution
method (MSM) [27,28]. Dependence of pH on electrode response
was examined (Figure 7): Adjusting the pH of the measured standard
solution with 1x10
-3
mol
-1
hydrochloric acid or sodium hydroxide
solutions (Figures 6 and 7).
Underwent response Sensors palladium according the equation
Nernstian with selectivity similar and the knowledge that the sensors
palladium prepare traditional because we prepare palladium disc,
and put the bottom of reference electrode .e electrode signal feels
palladium in another solutions whether the sample solution sea water
or others and, of course, used plastic lms made of PVC, which showed
345 6789
20
30
40
50
60
70
80
90
100
110
10-3
10-7
P(E/V)
pH
Figure 7: Effect of pH standard solution 0.1M of PdCl2 on IRA-410.
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.0
0.5
1.0
1.5
2.0
2.5
1x10
-3
1x10
-4
1x10
-6
10
-7
1x10
-5
( KT(yp(t))
K(T
0
-T)
e
-t/T
E(m/V)
Time(sec)
Figure 8: Dynamic Response time of palladium electrode for step changes
in the concentration of pd(II) step B (1x 10
-7
)M in step F(1x10
-3
)M.
Citation: Kassem AT, El Said N, Aly HF (2014) New Ion Selective Sensitive Electrode of Pd (II) as Multisensor Based on IRA-410 via Low Cost
Oxidation Reduction Process. J Membra Sci Technol 4: 127. doi:10.4172/2155-9589.1000127
Page 4 of 7
Volume 4 • Issue 1 • 1000127
J Membra Sci Technol
ISSN:2155-9589 JMST an open access journal
1.0×10
−3
)M. e potentials versus time traces are shown in Figure 8.
As can be seen, the whole concentration range of plasticized membrane
electrode reaches its equilibrium responses in a very short time (<1s)
Membrane composition
Due to some similarities between the functional groups of IRA-410
with those of the previously reported ligating molecules for lanthanide
ions, and especially for palladium ion [2–6] as well as its negligible
water solubility, we decided to examine the suitability of IRA-410 as
potential ionophore in constructing some lanthanide ion-selective
electrodes. Our preliminary solution studies revealed that, NBPP forms
a quite stable complex with Pd (II) ion, which readily precipitates out
from dioxan solution. While the extent of complexation of transition
metal ions as well as other lanthanide such as Fe (III), Nd (III) and
Sm (III) with IRA-410 was found to be much lower, as was examined
by segmented sandwich membrane method [37]. Subsequently, the
ligand IRA-410 was tested as an ionophore for the preparation of a
variety of ions, mono, di, and trivalent metal ion-selective electrodes.
e potential response of various ion-selective electrodes based on
the proposed ionophore is shown in Figure 10. As expected, among
dierent cations tested, Pd (II) with the most sensitive response seems
to be suitably determined with the PVC membrane based on ligand
NBPP. While the response slope of the other ion-selective electrodes
are much lower the values expected from Nernstian equation, although
in a limited concentration range. e response of membrane electrode
depends on some parameters such as plasticizer–PVC ratio, amount of
ionophore and additive used since; the nature of plasticizer inuences
the dielectric constant of the membrane phase both the mobility of
ionophore molecules and the state of ligands [38-41]. It was expected
to play a key role in the determining the ion-selective electrode
characteristics. Polar plasticizers lead to the lowering of the membrane
resistance as compared with polar plasticizers, which contain other
functional groups with potential coordination sites which might [42]
compete with carrier us, several solvents such as THBE, EHBS,
DOP, o-NDPE, o-NPPE, and were tested (Figures 9-11). In fact, the
Pd (II) ion-selective electrode based on IRA-410 better than the other
examined mediators. It has a good Nernstian slope of 19.5 ± 0.2 mV
decade-1 over a wide of concentration range from 10
-1
to 2.5×10
-6
mol
l
-1
, with detection limit of 1.6×10
-6
mol l
-1
. On the other hand, THBE,
EHBS, DOP, o-NDPE and o-NPPE solvents give non-Nernstian slopes
of 12.5, 28, 14.6, 9.8, and 12.4, respectively.
Response of dierent anions: In preliminary experiments, various
PVC-membrane ion-selective electrodes with the synthesized ion pair
were prepared and tested for dierent anions. e potential response
of the electrode for dierent anions is shown in Figure 9: e results
exhibited signicantly high selectivity to palladium ion over other
anions. Hence, ion pair was selected as a carrier for preparation of
palladium selective electrode.
Preparation of sandwich membrane
A potentiometric method to determine ionophore complex
formation constants in solvent polymeric membrane phases, it requires
membrane potential measurements on two-layer sandwich membranes,
where only one side contains the ionophore. If both membrane segments
have the same ionic strength, it is convenient to assume that the activity
coecients for the complexed and uncomplexed ions are approximately
equal. In that case, they can be omitted and the complex constant is
related to the potential .is relationship allows for the convenient
determination of formation constants of ionophore complexes within
the membrane phase on the basis of transient membrane potential
the practical for response time of the ion selective electrode recorded
by changing of the Pd(II) concentration in solution from (1.0×10
−7
to
7 6 54321
-280
-260
-240
-220
-200
-180
-160
-140
-120
-100
-80
-60
-40
KTCIPB
NaTPB
NaTFPB
NBPP
E/mV
PPd+2
Figure 9: The Potential responses of pd(ll) membrane ISEs prepared with
different types of potential.
0 2 468 10 1
2
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
Ce
Sm
Fe
Nd
Pd
E/mV
pH
Figure 10: Effect of pH on the potential responses of pd(ll) ion-selective
electrode.
86420
200
300
400
E/mv
p
M
Figure 11: Potential response of various ion-selective membrane based on
IRA-410.
Citation: Kassem AT, El Said N, Aly HF (2014) New Ion Selective Sensitive Electrode of Pd (II) as Multisensor Based on IRA-410 via Low Cost
Oxidation Reduction Process. J Membra Sci Technol 4: 127. doi:10.4172/2155-9589.1000127
Page 5 of 7
Volume 4 • Issue 1 • 1000127
J Membra Sci Technol
ISSN:2155-9589 JMST an open access journal
measurements on two-layer sandwich membranes can be if ion pairing
neglected. Ion-selective electrode membranes were cast by mixing the
recorded membrane components to give a total cocktail mass of 181.8
mg in 2 ml of THF. e solvent THF allowed evaporating overnight. A
series of disks were cut with a cork borer from the parent membrane.
ese disks were conditioned overnight in each of metal chloride 0.01
M salt solutions shown in Figure 10 of Ce (III), Sm (III), Fe (III) and Nd
(III). All membrane electrode potential measurements were performed
at laboratory ambient temperature in unstirred salt solution (identical
to the conditioning and inner lling solution) versus Ag/AgCl reference
electrode. Sandwich membrane was made by pressing two individual
membranes (ordinary one without ionophore and one with the same
components and additional ionophore) together immediately aer
blotting them individually, dry with tissue paper. e combined
segmented membrane was then rapidly mounted into the electrode
body and immediately measured. e time required from making
the membrane sandwich contact until nal membrane potential
measurement was less than 1 min.
Sample preparation
Determination of palladium sample by Potentiometeric
titrations: THF (15.0 mL) was placed in the titration vessel and
the required volume of the investigated acid and two drops of the
indicator solution were added. e indicator electrode, either H2/Pd
or glass electrode and a SCE as the reference one were immersed in the
investigated solution and connected to a pH-meter. e solution was
then titrated with standard solution of (potassium hydroxide or sodium
methylate) and the potential was read aer each addition of titrant. e
test solution was stirred magnetically under a continuous stream of dry
nitrogen (Figures 9-11).
e optimization of permselectivity of membrane sensors
e optimization of permselectivity of membrane sensors is known
to be highly dependent on the incorporation of addition a membrane
components. In fact it has been demonstrated that, the presence of
lipophilic negatively charged additives improves the potentiometric
behavior of certain cation-selective electrodes by reducing the ohmic
resistance and improving the response behavior and selectivity [43,44].
Some of the lipophilic ions such as, potassium tetrakis (4-chlorophenyl)
borate (KTClPB), sodium tetra phenyl borate (NaTPB), sodium tetrakis
(1-imidazolyl borate) (NaIB) and sodium tetrakis (4-uorophenyl)
borate dehydrate (NaTFPB), were tested (Figure 12). It has been found
that, the suitable lipophilic additive which improves the sensitivity of
Pd (II) electrode was KTClPB with a good Nernstian slope of 19.5 ±
0.2 mVdecade-1. While the other lipophilic ions have slopes of 21, 13.6
and 9, respectively (Figure 11). Shown that the potential response of
various ion-selective membranes based on IRA-410. e amount of
ionophore has eect on the electrode sensitivity. So that, amounts of
NBPP carrier (0.8, 1.2 and 1.6 mg) were examined. e results indicate
that, the membrane containing 1.20 mg NBPP ionophore exhibits a
good Nernstian slope of 19.5 ± 0.2 mV decade-1 and high selectivity
of Pd (II) ion.
Eect of internal solution, response time and pH
e working of membrane electrode in relation to variation of
reference solutions was investigated. It was found that, the variation
of the concentration of the internal solution (10
-1
to 10
-4
mol
-1
of KCl
solution) causes signicant eect on corresponding potential response.
However a solution of 10
-3
moll
-1
KCl mixed with 10
-3
mol l
-1
[pdCl
4
]
-4
would be used as a suitable internal solution, it had a good slope 19.5 ±
0.2 mV decade-1. e detection limit, taken at the point of intersection
of the extrapolated linear segment of the calibration curve, was 1.6×10
-6
mol l
-1
. e static response time of the membrane electrode thus obtained
was <10 s. e sensing behavior of the electrode remained unchanged
when the potential recorded from low to high concentrations or vice
versa. e life time of the present electrode was at least 3 months. During
this time, the detection limit of the electrode remained almost constant
and the slope of the response decrease from 16.5 ± 0.2 to 16.1 ± 0.15 mV
decade
-1
. Aer this time the electrochemical behavior of the electrode
gradually deteriorates. e eect of pH on the response of the electrode
was studied over the pH range from 1 to 11 at dierent concentrations
(10
-2
to 10
-5
moll
-1
) of Pd (II) solution. e pH of solutions was adjusted
with either HCl or NaOH solutions. Potential remains constant at pH
range from 4 to 8 (Figure 12). e increase of potential below pH~ 4
may be ascribed to interference by H+ ion and the decrease of potential
above pH= 8 may be due to formation of some hydroxyl complex of
the pd(II) ions in solution from hydrolysis of palladium chloride. e
performance of the electrode was assessed in partially non-aqueous
media using ethanol–water mixture; it is observed that the electrode
functions well in presence of up to 10% (v/v) non-aqueous (alcoholic)
content. Higher alcoholic content disturbs the functioning of system
(Figure 12).
Electrode selectivity
e inuence of interfering ions on the response behavior of
ion-selective membrane electrode is usually described in terms of
selectivity coecient log Potpalladium B. e potentiometric selectivity
coecients log Pot palladium B of palladium electrode were evaluated
by (SSM) and (MSM)(27,30,31). e resulting values of the selectivity
coecients are summarized in Table 3. It is evident from the selectivity
coecients data, that the sensor exhibits a high performance for Pd
012 3 4 567 8
9
140
160
180
200
220
240
260
280
300
E/mV
P
pd(II)
moll
-1
Figure 12: Effect of lipophilic anions on potential responses of
pd(ll) selective electrode based on IRA-410 ionophore for different
concentrations.
Interfering ions
()
log
MPM
p II
K =
Ce
3+
−3.00
Sm
3+
−2.89
Fe
3+
−3.02
Nd
3+
−3.10
Table 3: Comparison of the selectivity coefcients of different pd(II) electrodes.