Rapid, synergistic extractive spectrophotometric determination of copper(II) by using sensitive chromogenic reagent N″,N?-bis[(E)-(4-fluorophenyl) methylidene]thiocarbonohydrazide

Article abstract of DOI:10.1016/j.saa.2015.02.022

Abstract A rapid and simple spectrophotometric method was developed for the determination of copper(II) by using newly synthesized chromogenic reagent, N″,N?-bis[(E)-(4-fluorophenyl)methylidene]thiocarbonohydrazide [bis(4-fluoroPM)TCH]. The reagent is highly sensitive and it forms yellow colored ternary complex with copper(II) in presence pyridine having composition 1:1:2 (M:L:Py) in the acidic pH range. Absorption of colored complex in amyl acetate is measured with reagent as a blank at kmax 375 nm. The synergistic effect is observed due to pyridine forming adduct with reagent in the organic phase. Beer's law was obeyed in the concentration range from 2.0 to 14 μg mL^-1 for copper(II)-[bis(4-fluoroPM)TCH]-Py complex. Molar absorptivity and Sandell's sensitivity values for Cu(II)-bis(4-fluoroPM)TCH]-Py complex are 0.42545 × 10⁵ and 0.0014 μg/cm², respectively. The selectivity of the developed method was checked in the presence of various foreign ions. The developed method showed relative standard deviation (R.S.D.) of 0.13% for n = 10. The composition of Cu(II)-[bis(4-fluoroPM)TCH]-Py complex was determined by known methods such as Job's method of continuous variation, mole ratio method and slope ratio method. It is found that the ternary complex is stable for more than 24 h. Various factors influencing on the degree of complexation, such as, effect of pH, reagent concentration, synergent concentration, solvent etc. were studied. The accuracy and reliability of method was verified by AAS. This method is found to be simple, rapid and reproducible.

Full text of DOI:10.1016/j.saa.2015.02.022

Accepted Manuscript
Rapid, synergistic extractive spectrophotometric determination of copper(II) by
using sensitive chromogenic reagent N’ ’, N’ ’ ’ -bis [(E)-(4-fluorophenyl)
methylidene] thiocarbonohydrazide
Rekha A. Nalawade, Avinash M. Nalawade, Ganesh S. Kamble, Mansing A.
Anuse
PII:
S1386-1425(15)00174-2
http://dx.doi.org/10.1016/j.saa.2015.02.022
SAA 13312
DOI:
Reference:
To appear in:
Spectrochimica Acta Part A: Molecular and Biomo-
lecular Spectroscopy
Received Date:
Revised Date:
Accepted Date:
25 September 2014
27 December 2014
4 February 2015
Please cite this article as: R.A. Nalawade, A.M. Nalawade, G.S. Kamble, M.A. Anuse, Rapid, synergistic extractive
spectrophotometric determination of copper(II) by using sensitive chromogenic reagent N’ ’, N’ ’ ’ -bis [(E)-(4-
fluorophenyl) methylidene] thiocarbonohydrazide, Spectrochimica Acta Part A: Molecular and Biomolecular
Spectroscopy (2015), doi: http://dx.doi.org/10.1016/j.saa.2015.02.022
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Rapid, synergistic extractive spectrophotometric determination of
copper(II) by using sensitive chromogenic reagent N'', N'''-bis [(E)-(4-
fluorophenyl) methylidene] thiocarbonohydrazide
a, b
Rekha A. Nalawade , Avinash M. Nalawade , Ganesh S. Kamble , Mansing A. Anuse
b
a
a *
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a
Analytical Chemistry Laboratory, Department of Chemistry, Shivaji University, Kolhapur
416004, Maharashtra, India
b
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Department of Chemistry, Lalbahadur Shastri College, Satara, 415002
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Abstract
A rapid and simple spectrophotometric method was developed for the determination of
copper(II) by using newly synthesized chromogenic reagent, N'',N'''-bis[(E)-(4-
fluorophenyl)methylidene]thiocarbonohydrazide [bis(4-fluoroPM)TCH ]. The reagent is
highly sensitive and it forms yellow colored ternary complex with copper(II) in presence
pyridine having composition 1:1:2 (M:L:Py ) in the acidic pH range. Absorption of colored
complex in amyl acetate is measured with reagent as a blank at λmax 375 nm. The synergistic
effect is observed due to pyridine forming adduct with reagent in the organic phase. Beer’s
-1
law was obeyed in the concentration range from 2.0 to 14 µg mL for copper(II)- [bis(4-
fluoroPM)TCH ]- Py complex. Molar absorptivity and Sandell’s sensitivity values for Cu(II)-
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bis(4-fluoroPM)TCH]- Py complex are 0.42545 x10 and 0.0014 ug/cm , respectively. The
selectivity of the developed method was checked in the presence of various foreign ions. The
developed method showed relative standard deviation (R.S.D.) of 0.13% for n=10. The
composition of Cu(II)- [bis(4-fluoroPM) TCH]- Py complex was determined by known
methods such as Job’s method of continuous variation, mole ratio method and slope ratio
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method. It is found that the ternary complex is stable for more than 24 h. Various factors
influencing on the degree of complexation, such as, effect of pH, reagent concentration,
synergent concentration, solvent etc were studied. The accuracy and reliability of method
was verified by AAS. This method is found to be simple, rapid and reproducible.
Keywords: Copper(II), Synergistic extraction, [bis(4-fluoroPM)TCH], Pyridine,
Spectrophotometry, Real sample analysis
*Corresponding author: Tel: +91 231 2609380; Fax: +91 231 2692333
E-mail: mansinganuse@yahoo.co.in
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Introduction
th
Copper is the 25 most abundant element in the earth’s crust. It occurs to the extent of 68
ppm by weight [1]. Copper and its salts are highly toxic to lower organism(s) much more
than man. It is however, an essential constituent of certain proteins. In biological system,
copper counter acts the toxicity of zinc suggesting Cu-Zn antagonism [2]. Copper is most
important constituent of respiratory pigment of arthropods and mollusca. Copper is widely
distributed in animal tissues and is one of the essential elements in the human body.
Deficiency of copper in body results in different health problems like anaemia, hair kinky,
Wilson disease [3] and jaundice. Copper and its salts are used in industries, laboratories,
medicines, foods and beverages.
Copper (II) forms chelate complex with many organic reagents containing ‘N’, ‘O’ and ‘S’
donor atoms. According to Pearson’s HSAB rule [4], strong bonding has been found between
Cu(II) and ‘S’ donor atom containing chelate ligands, as copper is soft acid and sulphur
containing ligands are soft bases.
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Several analytical techniques have been used for determination of Cu(II), they include
atomic absorption spectrometry [5-12], voltametry [13-15], spectrophotometry [16-18]
inductive coupled plasma-emission spectrometry [19-21] and inductive coupled plasma-
mass spectrometry [22]. A number of spectrophotometric reagents have been used for
determination of copper(II), but very few reagents are applied for synergistic extraction,
separation and determination. In synergism, chelating ligand and solvating solvent when used
together, extract a metal ion with enhanced efficiency compared to their individual action. In
+n
a common form of synergistic extraction, a metal ion M is extracted by mixture of acidic
chelating reagent HR and uncharged basic reagent ‘S’. The joint action of reagents is
especially pronounced in those cases where co-ordination capacity of metal ion is not fully
achieved in MRn chelate. Then extractant gives a mixed complex MRnSn which is extracted
with much greater efficiency than parent chelate [23].
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Sandell and Marczenko have suggested various methods for determination of
copper(II) [24, 25]. Several complexing agent have been reported for synergistic extraction
and spectrophotometric determination of copper(II). However, most of these reagents suffer
from various limitations such as heating [26], more time for color development [27], longer
extraction period [28], narrow Beer’s range [29, 30], use of optical fiber [31], interferences
from many ions [32-34] and use of surfactants for color stability [35].
Determining of trace amounts of copper(II) from different matrices is becoming
increasingly important because of its biological role and use of copper and its salts in
industries laboratories, medicines, foods and beverages. Also copper is constituent of
pharmaceuticals, alloys, ores, fertilizers and pesticides. Hence, rapid and sensitive methods
for its determination are in great demand. Hence, herein we have proposed synergistic, highly
sensitive, simple and rapid spectrophotometric method for extraction and spectrophotometric
determination of Cu(II) with improved performance when compared with other
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spectrophotometric methods [36-48] (Table1). The proposed method has been successfully
applied for determination of copper(II) in alloys, fertilizers, pesticides, pharmaceuticals, food
materials and synthetic mixtures.
2.
Experimental
2.1. Apparatus
Absorption spectra were obtained with Lab Junction digital spectrophotometer model
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LJ-1306 using 1 cm quartz cell. A model LI-120 Elico digital pH meter with combined glass
electrode was used for measurement of pH.
2.2. Standard copper(II) solution and solution of other cations and anions
−1
A stock solution of Cu(II) (1 mg mL ) was prepared by dissolving 3.933 g of cupric
sulphate pentahydrate (CuSO ·5H O, Merck), in water containing 1.0 mL of concentrated
sulphuric acid (H SO , s. d. fine) and standardized by a known method [23]. All working
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solutions were prepared by diluting the stock solution suitably with water. All other
chemicals and solvents used were of analytical reagents grade. Double distilled water was
used throughout the experiment.
Solutions of different cations and anions were prepared by dissolving weighed
quantities of there salts in water or dil. HCl [49]. Different synthetic mixtures containing
Cu(II) were prepared by combining with commonly associated metal ions in definite
composition [25].
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2.3. Synthesis
of
N'',N'''-bis[(E)-(4-fluorophenyl)methylidene]thiocarbonohydrazide
[bis(4-fluoroPM)TCH ].
The synthesis of ligand involves two steps,
(a) Preparation of thiocarbohydrazide (TCH): There are several reported methods for the
synthesis of TCH [50-54]. Amongst those methods, we used the method [54] in which 2
moles of hydrazine hydrate was refluxed for 2 h in an aqueous medium with 1 mole of
carbon disulphide to give thiocarbohydrazide (TCH) (Eq.1).
S
Heat
S
H N NH2
H N
2
NH2
H2S
2
2
+
+
S
Water
NH
NH
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0
1
2
………..(1)
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1
(b) 1:2 molar solutions of TCH and p-fluoro benzaldyde are refluxed in alcohol as a solvent
and glacial acetic acid as a catalyst to give N'',N'''-bis[(E)-(4-fluorophenyl)methylidene]
thiocarbonohydrazide [bis(4-fluoroPM)TCH](Eq.2).
H N NH
NH NH2
F
CHO
+ 2
2
S
glacial acetic acid
NH
CH
F
CH
N
NH
N
F
S
1
3
………………(2)
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Purity of the reagent was checked by melting point, TLC, IR and NMR. A 0.01 M
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stock solution of [bis(4-fluoroPM)TCH] was prepared by dissolving 0.299 g in a 100 cm of
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amyl acetate.
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2.4. Recommended procedure
−1
Copper(II) solution (10 µg mL ) were taken in 25.0 mL calibrated flasks and pH was
adjusted to 2.5 with dil. hydrochloric acid and sodium hydroxide. The solution was
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transferred into 125 mL separatory funnel, followed by addition of 1 mL of 0.002 mol L
−1
[bis(4-fluoroPM)TCH], 4 ml amyl acetate, 5.0 mL of 0.5 mol L pyridine in amyl acetate.
Two phases were equilibrated to 3 min. The yellow colored organic extracts were collected
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over anhydrous Na SO to remove the traces of water. The solutions were then transferred
into 10 mL standard volumetric flask and made up to the mark with amyl acetate. The
absorbance of the extracted organic complex was measured at λmax 375 nm against a reagent
blank prepared in the same way without addition of Cu(II). Unknown amount of Cu(II) was
determined from the calibration graph prepared in the same manner.
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3.
Results and discussion
3.1. Absorption spectra and spectral characteristics of colored complex
Copper(II) forms a yellow ternary complex with [bis(4-fluoroPM)TCH] with
proportion of 1:1:2 (M:L:Py) in the presence of pyridine as an auxiliary ligand, which was
extracted into amyl acetate at pH 2.5. The absorption spectra of complex in amyl acetate
were studied over the wavelength range 300–800 nm (Fig. 1.). The colored organic complex
Cu(II)- [bis(4-fluoroPM)TCH]-Py showed maxima at λmax 375 nm in amyl acetate. Complex
was stable for more than 24 h. The optimum conditions for the effective extraction of Cu(II)
was established by studying the effect of pH, reagent concentration, pyridine concentration,
choice of solvent, equilibrium time and interference of various diverse ions.
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3.2. Effect of pH
The absorbance of complex was studied for wide range of pH from 1 to 10. The
extraction of Cu(II) was carried out with the bis[4-fluoroPM]-TCH in presence and absence
of pyridine. The study showed maximum absorbance in the pH range 2.5-5.0 in the absence
of pyridine for [bis(4-fluoroPM)TCH]-Cu complex. However, in presence of pyridine, there
was enhancement of absorbance and therefore it shifted in the pH range from less acidic to
more acidic pH range i. e. 1.5-4.0, showing synergistic effect on absorption [bis(4-
fluoroPM)TCH]-Cu(II)-Py complex (Fig. 2).
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3.3. Effect of solvent
Various organic solvents were examined for the extraction of Cu(II) with [bis(4-
fluoroPM)TCH]-TCH (0.002 M) in the presence of pyridine.
The ascending percentage extraction (%E) values for Cu(II)-[bis(4-fluoroPM)TCH]-
Py complex were in the order of kerosene (no extraction) < carbon tetrachloride (0.01 %) <
1,2-dichloroethane (0.014 %) < butyl alcohol (32.0 %) < amyl alcohol (47.7 %) <
chloroform (54.9 %) < toluene (69.4 %) < dichloromethane (70.0 %) < benzene (92.2 %) <
xylene (92.6%) < methyl iso-butylketone (96.3 %) < amyl acetate (99.9 %). Among these
solvents, amyl acetate was used for further extraction as it showed high distribution ratio of
Cu(II)-[bis(4-fluoroPM)TCH])-Py complex and improved stability of the complex.
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3.4. Effect of [bis(4-fluoroPM)TCH]concentration
The concentrations of [bis(4-fluoroPM)TCH] in amyl acetate were varied within
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the range 1 x10 to 10 x10 (0.00001 to 0.001) mol L . The reagents were added into a10
−1
−1
µg mL of Cu(II) ion solution. In the absence of pyridine, absorbance was measured
−
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-4
according to the developed procedure. It was observed that, 6.0 mL of 0.001 mol L (6x10
−1
mol L ) reagent concentration was required for full color development. In the presence of
−1
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−1
pyridine, the required reagent concentration was 0.8 mL of 0.002 mol L (1.6x10 mol L )
for full color development. However, in order to ensure the complete complexation, 1.0 mL
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of 0.002 mol L reagent was recommended. Requirement of very low reagent concentration
of reagent in presence of pyridine shows synergistic effect on absorbance. Excess of reagent
−1
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does not affect the absorbance of the complex up to 2.5 mL of 0.002 mol L (5x10 mol
−1
L ). With further increase in reagent concentration the absorbance goes on decreasesing
(Fig. 3).
3.5. Effect of shaking time
The shaking time was varied from 0.25 to 60 min in the absence and in presence of
pyridine. The optimum shaking time of 3 min for Cu(II)-[bis(4-fluoroPM)TCH]-Py complex
was established for full color development in the presence of pyridine. In the absence of
pyridine, absorbance was lowered and required more shaking time (5 min) for full color
development. Prolonged shaking time has no adverse effect on the extraction of Cu(II) in the
presence of pyridine. Hence, a shaking time of 5 min was used for further study.
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3.6. Effect of concentration of pyridine (Auxillary ligand)
Cu(II)-[bis(4-fluoroPM)TCH] complex formation was influenced by pyridine
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concentration. Copper (II) (10 ug ml ) was equilibrated with 1mL of 0.002mol L [bis(4-
−1
fluoroPM)TCH] in presence of 0 to 5.0 mL of 0.5 mol L concentration range of pyridine.
The absorbance of Cu(II)-[bis(4-fluoroPM)TCH] complex is found to decrease after 6 h in
the absence of pyridine. However, absorbance of Cu(II)-[bis(4-fluoroPM)TCH] complex
−1
increases with pyridine concentration and remains constant above 3.0 mL of 0.5 mol L
pyridine, indicating the formation of an adduct with pyridine . Therefore, 5.0 mL of 0.5 mol
−1
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L pyridine was used in recommended procedure.
3.7. Effect of color stability of complex
Copper(II)-[bis(4-fluoroPM)TCH]-Py complex shows stable absorbance for more than
24 h in presence of pyridine in amyl acetate solution, while in the absence of pyridine, the
absorbance was low and it also showed decrease after 6 h. Hence, study of Cu(II)- [bis(4-
fluoroPM)TCH]- Py complex was carried out in presence of pyridine.
3.8. Beer’s law, sensitivity, precision and accuracy of the method
Studies of Cu(II)- [bis(4-fluoroPM)TCH]- Py complex obeys the Beer’s law over the
-
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concentration range 2.0 to 14 µg mL of copper(II). The precision of the proposed method
was ascertained from the set of five replicates of fixed amounts of the Cu(II) samples. To
determine the accuracy of the proposed method, different amount of samples containing
Cu(II) were taken within the optimum Beer’s range limits and analyzed by the recommended
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procedure. Molar absorptivities and Sandell’s sensitivities of the proposed method in
presence and absence of pyridine were summarized in Table 2.
3.9 Ringbom’s plot for complexes
Beer’s optimum concentration range was evaluated by Ringbom’s plot. Plot shows
-1
sigmoid shape with linear segment at intermediate concentration values as 4 to 12 µg mL
for Cu(II)-[bis(4-fluoroPM)TCH]- Py complex.
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3.10. Stoichiometry of the complex
The composition of the Cu(II)- [bis(4-fluoroPM)TCH]- Py complex was ascertained
by slope ratio method by plotting the graph of log D[Cu(II)] against log C[bis(4-fluoroPM)TCH], the
plots were linear having the slopes 0.93 and 0.92 at pH 8.0 and pH 9.0 respectively with
-1
fixed 0.5 mol L pyridine concentration (Fig. 4). And the plots for log D[Cu(II)] against log
[Pyridine] shows slopes of 1.70 and 1.75 at pH 8.0 and pH 9.0 respectively with fixed reagent
concentration (Fig. 5).
From graphs, the probable composition of extracted species was found to be 1:1:2
C
(metal:Ligand:pyridine). The composition of extracted species was also confirmed by mole
ratio method [55] and Job’s method of continuous variations [56] which are shown in Fig. 6
and 7, respectively. The probable structure of complex is shown in Fig. 8.
The reactions of copper(II) with the reagent and pyridine may therefore be
represented as follows by the equation (3) and (4).
+
+
+
[Cu(H
2
O)
O)
4
]
(aq.) + R-SH (Org.)
[Cu(H
2
O)
2
(R-S)] (Org.) + H (aq.) + 2H
2
O …(3)
….(4)
[Cu(H
2
2
(R-S)] (Org.) + 2 Py (Org.)
[Cu(R-S)(Py)
2
]
2
(Org.) + 2H O
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[bis(4-fluoroPM)TCH] is a sulphur containing chelating agent which reduces
copper(II) to copper(I) and then forms chelate. In the first step the charge on the cation is
removed by addition of thiol group. Then in second step, coordinated water molecules are
removed by auxiliary ligand (pyridine) to form neutral complex.
3.11 Effect of diverse ions
−1
The selectivity of the method was investigated by the determination of 10 µg mL of
Cu(II) in the presence of number of cations and anions within a relative error of ±2%
(Table 3). The interference of cations was removed by using suitable masking agent, thus
making the method more selective.
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4.
Applications
4.1. Separation of copper(II) from associated metal ions
[Bis(4-fluoroPM)TCH] is used for the separation and determination of Cu(II) from
associated metal ions containing Co(II), Fe(III), Ni(II), Bi(II), Al(III), Zn(II), Cd(II), Hg(I),
Pb(II), Pd(II), Ag(I), Cr(III) and Au(III) by its extraction with recommended procedure
(Table 4).
In the separation of copper(II) from chromium(III), under optimum conditions of
copper(II) extraction, chromium(III) was remained quantitatively in the aqueous phase. The
aqueous phase was evaporated to moist dryness by treating with 5.0 mL conc. HNO
3
followed by HCl. The residue was dissolved in water and diluted to appropriate volume.
Chromium(III) ions from aqueous phase was determined by standard method [25]. Cu(II)-
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[bis(4-fluoroPM)TCH]-Py complex was estimated spectrophotometrically at 375 nm against
reagent blank.
Copper(II) was also separated from Co(II), Fe(III), Ni(II), Bi(II), Al(III), Zn(II),
Cd(II), Hg(I), Pb(II), Pd(II), Ag(I) and Au(III) by following the recommended procedure
involving [bis(4-fluoroPM)TCH]. However, these metal ions interfered with extraction of
copper(II). Therefore, Co(II), Ni(II), and Cd(II) were masked with 0.8 mg thiocynate; Fe(III)
and Pb(II) were masked with 5 mg tartarate; Bi(II), Al(III) and Pd(II) were masked with 0.03
mg citrate and Ag(I), Au(III) were masked with 0.01 mg thiosulphate. The masked metal
ions remain in the aqueous phase quantitatively as an anionic complex and were
subsequently demasked by evaporation to moist dryness by treating with 2.0 mL of conc.
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HClO and susquently by conc. HCl. The residue was dissolved in water, diluted to
appropriate volume and metal ions were determined spectrophotometrically by standard
methods [24, 25, 49, 57, 58]. The absorbance of Cu(II)-[bis(4-fluoroPM)TCH]- Py complex
from organic phase was measured at 375 nm against reagent blank.
4.2. Determination of copper(II) from synthetic mixtures
-1
Several synthetic mixtures of varying compositions containing 10 µg mL of Cu(II)
and associated metal ions of known concentration were added, followed by respective
masking agents. Extraction of copper(II) was achieved by employing [bis(4-fluoroPM)TCH]
by recommended procedure. The results obtained were in good agreement with the amount
added (Table 5).
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4.3. Analysis of copper(II) from alloys
In order to assess the analytical applicability of proposed method, copper(II) was
determined in standard alloys such as Monel metal and Brass (Shubh Chemi Incorporate,
Mumbai), Nickel-Base alloy (BCS-387) and Cast–Iron 33b. About 0.1 g of each alloy was
dissolved in 5.0 mL of aqua regia followed by heating almost to dryness and the nitrate was
expelled from the residue using 3.0 mL of conc. HCl. The solution was filtered and made up
to 100 mL with water. Suitable aliquots of these solutions were taken and Cu(II) was
determined by using [bis(4-fluoroPM)TCH] separately with recommended procedure. The
results were confirmed by using atomic absorption spectrophotometer (Table 6).
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2
4.4. Analysis of copper(II) from pharmaceutical allopathic samples
Copper(II) was also extracted and determined from pharmaceutical allopathic
samples such as Antoxid, Supractive. A known weight of sample was dissolved in 5.0 mL of
aqua regia and organic matter, if any, was removed by evaporation of solution upto moist
dryness on a hot plate at a low temperature to avoid violent spurting of organic matter. The
obtained residue was further dissolved in 1:1 HCl and filtered through Whatmann filter paper
No. 1. The filtrate was diluted with water to 10 mL in a volumetric flask. The analysis of
Cu(II) was carried out by employing the recommended general procedure. The results were
confirmed by atomic absorption spectrophotometer (Table 7).
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4.5. Analysis of copper(II) from ayurvedic samples
The proposed method was applied for the determination of copper(II) in ayurvedic
samples such as Arogyavardhini Rasa, Mahalaxmi vilas, Smrutisagar Rasa, Arshakuthar Rasa.
A known weight of (1 tablet) sample was dissolved in 5.0 mL of aqua regia. The organic
matter was destroyed by treatment with 2.0 mL of conc. HClO4. The solution was evaporated
to moist dryness. The residue was dissolved in hot dil. HCl and filtered through Whatmann
filter paper No. 1. The filtrate was diluted to required volume with water. An aliquot of Cu(II)
containing solution was analyzed by the recommended procedure. The results were in good
agreement with those obtained by atomic absorption spectrophotometer (Table 8).
1
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1
1
1
1
1
4.6. Analysis of coppert(II) from homeopathic pharmaceuticals
An aliquot (3.0 mL) of each homeopathic pharmaceutical sample was used for
determination of copper(II) by the developed spectrophotometric method, and the results were
found to be in good agreement with those obtained by AAS (Table 9).
1
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7
8
4.7. Analysis of copper(II) from food materials
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The proposed method was also applied for the determination of Cu(II) in food materials.
Food material samples were collected locally and crushed in a mortar. A weighed amount of
o
each sample was taken into a silica crucible, heated to oxidized organic matter at 80 C in a
crucible heater for 2 h. The sample was dissolved in 5.0 mL of aqua regia solution and
4
evaporated upto moist dryness on a hot plate at a low temperature. Concentrated HClO was
added and evaporated to moist dryness and boiled with water, then filtered through ordinary
filter paper. The residue was washed with hot water. The filtrate was taken in a 25 mL
14

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measuring flask and diluted up to mark with water. An aliquot of 5.0 mL was taken and
determined by the developed procedure and confirmed by an atomic absorption
spectrophotometer (Table 10).
4
5
4.8. Analysis of micronutrient fertilizer and pesticide samples
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To investigate the applicability of the present method for analysis of Cu(II) in
micronutrient fertilizer and pesticide, the sample (3.0 mL) was evaporated nearly to dryness
3
with a mixture of a 10.0 mL of conc. HCl and 5.0 mL conc. HNO . This procedure was
1
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repeated for five times and heated to dense white fumes until the solution became clear and
free from residue. The resulting solution was then cooled and filtered through Whatmann
filter paper No. 1 and quantitatively transferred into a 100 mL calibrated flask and made upto
the mark with water. An aliquot (1.0 mL) of each sample was determined as described under
the developed method The results of fertilizer sample analyzed by the recommended
spectrophotometric method were found to be in good agreement with those obtained by AAS
(Table 11 and 12).
3. Conclusion
The synthesized reagent [bis(4-fluoroPM)TCH] has been proved to be highly
sensitive for extraction and spectrophotometric determination of copper(II) when compared
to other spectrophotometric methods. It is observed to be applicable for the determination of
copper(II) in binary, synthetic mixtures and various real samples with satisfactory results.
-1
Salient features: (i) Trace concentration of copper(II)[10 µg mL ] can also be determined by
using this new analytical chromogenic reagent. (ii) Very low reagent concentration is
required for quantitative determination of copper(II). (iii) The developedextraction procedure
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7
is a single stage. (iv) The yellow colored ternary complex is stable for more than 24 h. (v)
[bis(4-fluoroPM)TCH] form complex with copper(II) in acidic medium in the presence of
pyridine and used as a synergent with probable stoichiometry of extracted species as 1:1:2
(M:L:Py). (vi) The selectivity was enhanced by the use of suitable masking agents. (vii) The
developed method is simple, reproducible, rapid, highly sensitive, selective and used for
separation and determination of copper(II) in real samples and synthetic mixture of
associated metal ions.
8
9
0
Novelty
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Copper(II) was extracted and determined spectrophotometrically in acidic pH
solution by the mixture of F/Cl/Br-TCH and pyridine. The sensitivity and absorptivity is
greater than our previous 2’,4’-dinitro APTPT chromogenic reagent [59]. There was
enhancement of absorbance in presence of pyridine which showed the synergistic effect and
stability of complex was also increased by chelate formation. The proposed method is very
simple, selective and rapid. The developed analytical method is proved to be reliable for
analysis of real samples, which is confirmed by AAS.
Abbreviations
[bis(4-fluoroPM)TCH]
4’-chloro PTPT
N'',N'''-bis[(E)-(4-fluorophenyl)methylidene]
thiocarbonohydrazide
1-(4’-chlorophenyl)-4,4,6-trimethyl(1H,4H)-2-
pyrimidine thiol
2’,4’-dinitro APTPT
1-(2’,4’-dinitro aminophenyl)-4,4,6-trimethyl-1,4-
dihydropyrimidine-2-thiol
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9
0
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5
DMG
PAR
Py
Dimethylglyoxime
4-(2-Pyridylazo) resorcinol
Pyridine
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1
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2
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References
[1] Lee J. D., Concise Inorganic Chemistry, Fifth edition, Published by Blackwell
Science Ltd, London, 1996.
[2] Hart E. B., Steenbock H., Waddell J, Elvahjem A., J. Boil. Chem. 77 (1928) 797.
[3] Scheinberg H., Morell A. G., Inorganic Biochemistry; Eichhorn, G. L., Eds.; Elsevier:
New York, 1973; Vol. 1, p 306.
[4] Pearson R. G., J. Am. Chem. Soc. 85 (22) (1963) 3533–3539.
[5] Watson E., Nucl. Active 30 (1984) 31.
1
1
1
1
1
1
1
[6] Hunt D. T. E.,. Wilson A. L, The Chemical Analysis of Water, The Royal Society of
Chemistry, Oxford 398 (1986)
[7] Jain V. K., Sait S. S., Shrivastav P., Agrawal Y. K., Talanta 45 (1997) 397.
[8] Soyak M., Frensen's Environ. Bull. 7 (1998) 383.
[9] Hynuntee S., Sennchoi H., Bull. Korean Chem. Soc. 21 (2003) 1705.
[10] Bakireioglu Y., Bakireiouglu D., Akman S., Anal. Lett. 37 (2004) 1937.
[11] Taher M. A., Moberakeh S. Z. M., Mohamedesi A. R., Turk. J. Chem. 29 (2005 ) 17.
1
1
1
2
2
2
2
2
2
7
8
9
0
1
2
3
4
5
[12] Pourreza N., Ghanemi K., Spectrosc. let. 39 (2006) 127.
[13] Gillain G., Duyckarets G., Disteche A., Anal. Chim. Acta 106 (1979) 23.
[14] Giancarlotorsi C. L., Coll. Czech., Chem. Commun. 68 (2003) 1437.
[15] Praveen Kumar M., Chandra M. P., Reddy S. J., Anal. Lett. 38 (2005) 463.
[16] Jadhav V. A., Vandre A. G., J. Indian Chem. Soc. 68 (1992) 186
[17] Asan, Andal M., Isolidak I., Anal. Sci. 17 (2001) 1125.
[18] Wei J., Teshima N., Ohno S., Sakia T., Anal. Sci. 19 (2003) 731.
[19] Ramesh K., Ramamohan K., Seshaiah K., Jaya kumar N. D., Anal. Lett. 34 (2001) 219
[20] Gub Y., Din B., Liu Y., Chang X., Meng S., Talanta 62 (2004) 209.
18

1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
[21] Liu Y., Liang P., Guo L., Talanta 68 (2005) 25.
[22] McLaren W., Jarnis K. E., Gray A. L., Houk R. S. (Eds), Handbook of Inductively
coupled plasma-mass Spectrometry, Backle and Son Ltd ,Glassgow, 226 (1992).
rd
[23] Vogel A.I., A Text Book of Quantitative Inorganic Analysis, 3 ed., Longmans
London, 1975.
rd
[24] Sandell E. B., Colorimetric Determination of Traces Metals, 3 ed., Interscience Publ.,
New York, 1965.
[25] Marczenko Z., Spectrophotometric Determination of Elements, Ellis
Limited, Chichester, 1976.
Horwood
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
[26] Qiao Z. K., Hou Z. Q., Jianyan L., Huaxue Fence 31(2) (1995) 105.
[27] Sun P. P., Wu B. C., Fenxi Shiyanshi 13 (5) (1994) 11.
[28] Garcia F., Vallvey L. F., Gines–Fernandez D., Espinosa H. P., Quim. Anal 7(4) (1988)
451.
[29] Molina F., Fernandez G. D., Bosque-Sendra M. J., Espinosa P., J. Pharm Biomed.
Anal. 6, (68) (1988) 1099.
[30] Morales A., Valladares L., Fresenius Z., Ana. Chem. 334 (1989) 53.
[31] Karayannis M. I., Talanta 41(10) (1994) 1645.
[32] Terashima K., Tomioka H., Jap. Analyst 18 (8) (1969) 998.
[33] Shinde V. M., Khopkar S. M., Anal. Chem. 41 (2) (1979) 342 .
[34] Katiyar G. S., Haldar B. C., Indian J. Chem. Soc. 61(4) (1984) 353.
[35] Kaur V., Malik A.K., Verma N., Anal. Lett. 40 (2007) 2360–2373.
[36] Desai J. M., Desai K. K., Asian J.Chem.11 (1999) 1313.
[37] Dalman O., Tufekc M., Nohut S., Guner S., Karabocek S., J. Pharm Biomed. Anal 27
(2002) 183-189.
[38] Giancarlotorsi C. L., Coll. Czech. Chem. 68 (2003) 1437.
19

1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
[39] Thipyapong K., Suksai C., Bull. Korean Chem. Soc. 24 (2003) 1767.
[40] Reddy K. H.,. Prasad N. B. L, Reddy T. S., Talanta 59 (2003) 425-433
[41] Kocharekar A., Thakkar N. V., J. Sci. Ind. Res. 63 (2004) 383-286.
[42] Bellkhouche M. A., Villemin D. D., Solvent Ext. Ion Exchange 23 (2005) 677-693.
[43] Fu D., Yuan D., Spectrochima Acta, Part A 66 (2007)434-4367.
[44] Kumar A., Sharma P., Chandel L. K., Kalal B. K., Kunsaji-Mate S., J.Inch Phenom.
Macrocycle Chem. 62 (2008) 285-292.
[45] Ramanjaneyulu G., Reddy P. R., Reddy V. K., Reddy T. S., The Open Anal. Chem. J. 2
(2008) 78-82.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
[46] Panahi H. A., Elham M. K., Soudi M. H., Afr. J. of Pure and App. Chem. 2 (10) (2008)
96-99.
[47] Lokhande R. S., Sonawane R. P., Chavan U., Int. J. Chem. Sci. 9 (2) (2011) 503-509.
[48] Shawket K., Jawad A., Ali M., Ali I. R., J. Babylon University/Pure Appl. Sci.18 (5)
2013.
[49] Flaschka H. A., Barnard Jr. A. J., Chelates in Analytical Chemistry, A collection of
monographs, vol.4, Mercel Dekkar Inc., New York, 1972.
[50] Stolle R., Bowel P. E., Chem. Ber. 41 (1908) 1099.
[51] Authenrith, Hefner, Ber. 58 (1925) 2151.
[52] Audrieth, J. Org. Chem. 19 (1954) 733
[53] Kurzer F., M. Wilkinson, Chem. Rev. 113 (1969)
[54] Zheng L., Feng X., Zhao Y. , J. Het. Chem. 45 (2008) 1489.
[55] Yoe J. A., Jones A. L., Ind. Eng. Chem. Anal. Ed. 16 (1944) 11.
[56] Job P., Ann. Chim. 9 (1928) 113-203.
[57] Kamble G. S., Kolekar S. S., Han S. H., Anuse M. A., Talanta 81 (2010) 1088–1095.
[58] Anuse M. A., Chavan M. B., Chem. Anal. (Warsaw) 29 (1984) 409–420.
20

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[59] Kamble G. S., Kolekar S. S., Anuse M. A., Spectrochim. Acta Part A 78 (2011) 1455-
1466.
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Figure Captions:
Fig. 1. (A) Absorption spectra of [bis(4-fluoroPM)TCH] vs. Amyl acetate blank:
(B) Absorption spectra of Cu(II)-[bis(4-fluoroPM)TCH]-pyridine complex Vs.[bis(4-
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-
1
fluoroPM)TCH] blank Cu(II) = 10 µg mL ; [bis(4-fluoroPM)TCH] = 5.0 mL of 0.01 mol
-1
-1
L ; pyridine = 5.0 mL of 0.5 mol L ; pH = 2.5; shaking time = 5 min
1
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Fig. 2. (A) Effect of pH on the extraction Cu(II)-[bis(4-fluoroPM)TCH]-complex: (without
-
1
-1
pyridine) Cu(II) = 10 µg mL ; [bis(4-fluoroPM)TCH]-= 5.0 mL of 0.01 mol L ; pH =1 to
10; shaking time = 5 min; λmax = 375 nm
(B) Effect of pH on the extraction Cu(II)- [bis(4-fluoroPM)TCH]-Pyridine complex:
-
1
-1
(with pyridine) Cu(II) = 10 µg mL ; [bis(4-fluoroPM)TCH]-= 5.0 mL of 0.01 mol L ;
-1
pyridine = 5.0 mL of 0.5 mol L pH =1 to 10; shaking time = 5 min; λmax = 375 nm
Fig. 3. (A) Effect of reagent conc on extraction of Cu(II)- [bis(4-fluoroPM)TCH] complex:
-1
-1
Cu(II) = 10 µg mL ; [bis(4-fluoroPM)TCH]= 0.1-10 mL of 0.001 mol L ; pH =2.5;
shaking time = 5 min; λmax = 375 nm
(B) Effect of reagent conc on extraction of Cu(II)- [bis(4-fluoroPM)TCH]-pyridine
complex: Cu(II) = 10 µg mL-1 ;[bis(4-fluoroPM)TCH]= 0.1-5.0 mL of 0.002 mol L-1;
pyridine = 5.0 mL of 0.5 mol L-1; pH =2.5; shaking time = 5 min; λmax = 375 nm
Fig. 4. Slope ratio method: [Fixed pyridine concentration]
-1
-1
Cu(II) = 10µg mL ; pyridine = 5.0 mL of 0.5 mol L ; pH = 8.0 and 9.0; shaking time = 5
-5
-5
-1
min; λmax = 375 nm; [bis(4-fluoroPM)TCH]= 2 x 10 to 34 x 10 mol L
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Fig. 5. Slope ratio method: [Fixed reagent concentration]
-
1
-3
-3
-1
Cu(II) = 10 µg mL ; pyridine = pyridine = 5.0 x 10 to 175 x 10 mol L ; pH = 8.0 and 9.0;
-1
shaking time = 5 min; λmax = 375 nm; [bis(4-fluoroPM)TCH]= 1 ml 0.002 mol L (fixed
concentration)
Fig. 6. Mole ratio method
-
Cu(II) = 0.2 to1.8 mL of 7.86 x 10 mol L ; [bis(4-fluoroPM)TCH]= 1.0 mL of 7.86 x 10
4
-1
-4
-
1
-1
mol L ; pyridine = 5.0 mL of 0.5 mol L ; pH = 2.5; shaking time = 5 min; λmax = 375 nm
-
Fig. 7. Job’s method of continuous variation Cu(II) = 0.2 to 1.8 mL of 7.86 x 10 mol L ,
4
-1
1
1
1
1
1
1
-4
-1
[bis(4-fluoroPM)TCH]= 1.8 to 0.2 mL of 7.86 x 10 mol L ; pyridine = 5.0 mL of 7.86 x
-
4
-1
10 mol L ; pH = 2.5; shaking time = 5 min; λmax = 375 nm
Fig. 8. Structure of Cu(II)-[bis(4-fluoroPM)TCH]-pyridine complex
22

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Fig. 1.
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Fig. 2.
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Fig. 3.
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Fig. 4.
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Fig. 5.
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Fig. 6.
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Fig. 7.
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