A selective colorimetric and fluorescence chemosensing sensor for Cr3+ based on a rhodamine base derivative

Article abstract of DOI:10.1007/s11164-018-3407-z

A rhodamine-conjugated coumarin (L) was used in designing a selective fluorescence chemosensor for the determination of trace amounts of Cr³⁺ ions in acetonitrile–water (MeCN/H₂O (90:10, %v/v) solutions. The intensity of the fluoresce emission of the chemosensor is intensified upon addition of Cr³⁺ ions in MeCN/H₂O (90:10, %v/v) solutions, due to the formation of a selective 1:1 complex between L and Cr³⁺ ions. The fluorescence enhancement versus Cr³⁺ concentration has been found to be linear from 1.0 × 10^?7 to 1.8 × 10^?5 M and a detection limit of 7.5 × 10^?8 M. The proposed fluorescent probe proved to be highly selective towards Cr³⁺ ions as compared to other common metal ions and could be successfully applied to the determination of Cr³⁺ concentrations in some water and wastewater samples.

Full text of DOI:10.1007/s11164-018-3407-z

Res Chem Intermed
https://doi.org/10.1007/s11164-018-3407-z
A selective colorimetric and fluorescence chemosensing
sensor for Cr based on a rhodamine base derivative
3
+
1
,3
2,3
2,3
•
Morteza Hosseini
Mohammad Reza Ganjali
•
Mehdi Khoobi
4
•
Roghayeh Tarasi
,5
Received: 24 December 2017 / Accepted: 19 March 2018
Ó Springer Science+Business Media B.V., part of Springer Nature 2018
Abstract A rhodamine-conjugated coumarin (L) was used in designing a selective
3
fluorescence chemosensor for the determination of trace amounts of Cr ions in
?
acetonitrile–water (MeCN/H O (90:10, %v/v) solutions. The intensity of the fluo-
2
3?
resce emission of the chemosensor is intensified upon addition of Cr ions in
MeCN/H O (90:10, %v/v) solutions, due to the formation of a selective 1:1 complex
2
3
between L and Cr ions. The fluorescence enhancement versus Cr concentration
?
3?
-
has been found to be linear from 1.0 9 10 to 1.8 9 10 M and a detection limit
7
-5
-
of 7.5 9 10 M. The proposed fluorescent probe proved to be highly selective
8
3
towards Cr ions as compared to other common metal ions and could be suc-
?
3
?
cessfully applied to the determination of Cr concentrations in some water and
wastewater samples.
Keywords Fluorescence Á Chromium Á Enhancement Á Sensor
&
Morteza Hosseini
smhosseini@khayam.ut.ac.ir
1
2
3
4
5
Department of Life Science Engineering, Faculty of New Sciences and Technologies,
University of Tehran, Tehran, Iran
Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences
Research Center, Tehran University of Medical Sciences, Tehran 14176, Iran
Department of Pharmaceutical Biomaterials and Medical Biomaterials Research Center, Faculty
of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
Center of Excellence in Electrochemistry, School of Chemistry, College of Science, University
of Tehran, Tehran, Iran
Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences
Institute, Tehran University of Medical Sciences, Tehran, Iran
123

M. Hosseini et al.
Introduction
3?
An amount of 50–200 lg of Cr is essential for a balanced human or animal diet,
especially since the element plays a critical metabolic role on carbohydrates, lipids,
3
?
proteins, and nucleic acids in the body [1]. Furthermore, Cr is considered to be an
ecological contaminant emitted by different industrial and agricultural processes
[
2]. All this attracts much interest toward studies on the development of detection
methods for this ion in ecological and biological samples. The known methods to
this end include titrimetric determinations, flame atomic absorption, inductively
coupled plasma atomic emission, and X-ray fluorescence spectrophotometric
techniques as well as electrochemical methods. These techniques mostly require
cumbersome sample-preparation stages, as well as expensive and difficult to work
instruments, in addition to, in many instances, demanding controlled operating
conditions [3–6]. Consequently, the development of fast and facile procedures for
3
?
the analysis of Cr is always demanded and welcomed. The advent and use of
colorimetric and/or fluorimetric probes for the analysis of various analytes including
3
?
Cr has become quite popular in recent years, due to the ease, high selectivity,
sensitivity, high speed, comparatively negligible costs and direct visual perceptions
3
?
associated with these sensors. Most of the fluorescent probes reported for Cr
7–13] are based on fluorescence quenching, while there are few reports on
fluorescent probes functioning based on fluorescence enhancement mechanisms
14].
[
[
3
?
Cr is a paramagnetic species known for its efficient fluorescence quenching
properties as compared to other transition metal ions [15–18], and, hence, as
3
?
described earlier in the case of most Cr fluorescent probes, the signal transduction
through the so-called chelation-enhanced fluorescence (CHEF) is a challenge.
Rhodamine is a favorite reporter for fluorescent sensors [19, 20] owing to its high
absorption coefficient, high fluorescence quantum yield, large extinction coefficient
and their spirolactam ring-opening reaction, which can provide a strong fluores-
cence emission and a distinct color upon selective opening of rhodamine
spirolactam ring in the presence of specific metal cations. The structural properties
of the rhodamine framework, on the other hand, change it to an ideal choice for the
construction of CHEF-based OFF–ON fluorescent probes. This is due to the fact that
rhodamine undergoes equilibrium between its two highly fluorescent open-ring and
non-fluorescent spirocyclic forms (i.e. the on and off signals, respectively), each of
which has its own and completely unlike fluorescent properties [21]. Based on our
recent work on the development of a range of highly selective and sensitive
fluorescent sensors for various ions [22–28], here we report our research on the
application of a rhodamine B hydrazide (L) as an ionophore for the construction of a
3
?
Cr -selective fluorescent chemosensor.
1
23

A selective colorimetric and fluorescence chemosensing…
Experimental
Reagents
The chemicals were of the reagent grade and were obtained from Fluka and Merck.
The solution of metal ions was prepared from their nitrate salts of analytical grade
because of their good solubility.
Synthesis of 2-oxo-2H-chromene-3-carbonyl chloride
First, 5 mmol of salicylaldehyde (compound 1) dissolved in 10 ml dry ethanol.
Next, 5 mmol of diethyl malonate (compound 2), 0.005 ml of glacial acetic acid and
0
.05 ml of piperidine were added to the reaction mixture. This mixture was then
refluxed for 6 h (monitored by TLC), and the resulting white precipitate was filtered
and washed with cold ethanol several times, before being dried at ambient
temperature to obtain compound 3. Next, this white precipitate was dissolved in
1
00 ml of 0.5% NaOH and refluxed for 2 h, until a clear solution was achieved. This
solution was next acidified with HCl to reach a pH of 2, and cooled to 0 °C. In this
way, a white precipitate was obtained, which was filtered and washed with cold
ethanol, allowed to dry in ambient conditions and crystalized from ethanol
(
compound 4) (6.58 g, 82.2% yield) [29]. At last, to 2.5 mL of thionyl chloride in
toluene was added 0.18 g of compound 4 (1 mmol) and the resulting mixture was
refluxed at 80 °C for 6 h. Before the reaction was finished, the solvent of the
reaction mixture was evaporated to finally collect 2-oxo-2H-chromene-3-carbonyl
chloride (compound 5) without any further treatments.
Synthesis of rhodamine B hydrazide
The synthesis of rhodamine B hydrazide (compound 6) was carried out, as described
elsewhere [30]. According to this procedure, an excess of hydrazine hydrate
(
0.5 mL) was added to 15 mL of methanol solution containing 0.4 g of rhodamine
B hydrochloride, and the resulting mixture was subjected to refluxing in an N2
atmosphere until its pink color wore off. After 4 h, the mixture was cooled and
added to some distilled water, from which it was extracted using ethyl acetate
(6 9 25 mL). The organic phases were then mixed and dried with anhydrous
sodium sulfate, before being filtered, and concentrated under reduced pressure. This
yielded 0.31 g (77.5%) of rhodamine hydrazide 7.
1
H NMR (CDCl , 500 MHz): d 7.94 (bs, 1H, isoindoline ring), 7.46 (bs, 2H,
3
isoindoline ring), 7.12 (bs, 1H, isoindoline ring), 6.46-6.43 (m, 4H, xanthene ring),
6
.31 (bs, 2H, xanthene ring), 3.62 (bs, 2H, NH ), 3.35 (bs, 8H, NCH CH ), 1.18 (bs,
2 2 3
1
2H, NCH CH ).
2
3
123

M. Hosseini et al.
Synthesis of rhodamine-conjugated coumarin
The obtained crude acid chloride (compound 5) was dissolved in 10 mL of toluene.
To this solution was added dropwise a solution containing 0.2 g of potassium
carbonate and 20 mL of rhodamine hydrazide (0.456 g, 1 mmol). The resulting
mixture was then refluxed for 6 h under an N atmosphere before being cooled to
2
ambient temperature to obtain an orange precipitate. This product was filtered and
washed 3 times with 15 mL of cold toluene.
1
Yield: 75%; H NMR (CDCl , 500 MHz): d 9.95 (bs, 1H, NH), 8.79 (s, 1H, H
3
8
coumarin), 7.94 (bs, 1H, isoindoline ring), 7.62–6.78 (m, 11 H, 3H isoindoline, 4H
xanthene and 4H coumarin ring), 6.36 (bs, 2H, xanthene ring), 3.33 (bs, 8H,
NCH CH ), 1.16 (bs, 12H, NCH CH ).
2
3
2
3
Scheme 1 illustrates the sequence of steps for the preparation of rhodamine-
conjugated coumarin by hydrazine.
Apparatus
All fluorescence measurements were carried out on a Perkin-Elmer LS50
luminescence spectrometer.
Fluorescence measurements
A fluorimetric cell was filled with 3.0 mL of a solution of the fluorophore L
-
6
(
solution were acquired. The solution was simultaneously titrated with a standard
5 9 10 mol/L) in MeCN/H O (90:10, %v/v). Then, the emission spectra of the
2
3
?
Cr solution and the fluorescence variations were recorded. The emission intensity
at an excitation wavelength of 553 nm was measured. Spectral bandwidths of
monochromators for excitation and emission were 5 nm.
Results and discussion
Preliminary studies
To evaluate the reaction between the analytes and L, their UV–Vis absorption
spectra were monitored. During these studies, the affinity of L towards different
Scheme 1 Synthesis of rhodamine-conjugated coumarin (L)
1
23

A selective colorimetric and fluorescence chemosensing…
3
metal ions was visually evaluated (see Fig. 1). In the case of adding Cr , the color
?
-
of a 4.0 9 10 mol/L solution of L was instantaneously changed from colorless to
5
pink. In the case of the rest of the ions tested, however, no detectable color changes
3?
3
was observed except for Ce and Co which were much lower than that of Cr
?
2?
.
This was even the case after adding large excesses of the metallic ions. The result
indicated that the color changes were most probably due to the formation of a new
complex species with different electronic properties from that of the receptor L, and
3
?
2?
therefore a new color (pink) was observed, although Ce and Co ions were
caused to slightly change color.
-
5
The spectra obtained for titrating a 5.0 9 10 mol/L solution of L in
acetonitrile–water (MeCN/H O) (90:10, v/v) solution with standard
is illustrated in Fig. 2. This information
a
2
-
3
3?
5
.0 9 10 mol/L solution of Cr
indicates that L has a broad absorption band centered at 283 nm and 556 nm, most
probably due to its p ? p* transition. The intensity of the a bsorption peak at
kmax = 283 nm increased and a new peak appeared at 556 nm with a shoulder at
5
12 nm. A further three distinct isosbestic points were observed at 255, 293 and
31 nm, which are indicative of the formation of a stable complex between L and
3
Cr with a certain stoichiometry.
3
?
-5
Fig. 1 Color response of the receptor L in MeCN (4.0 9 10 mol/L) to the addition of cations
-
4
2?
4.0 9 10 mol/L in MeCN) under visible and UV light. From left to right: L ? Zn , L ? K ,
?
(
L ? Ni , L ? Hg , L ? Mg , L ? Cd , L ? Al , L? Co , L? Ce , L ? Cr , L only
2? 2? 2? 2? 3? 2? 3? 3?
123

M. Hosseini et al.
-
Fig. 2 Changes in the UV–vis spectra of L (5 9 10 M) upon addition of Cr (5 9 10 mol/L) in
5
3?
-3
2
MeCN/H O (90:10,% v/v)
Fluorescence titration
3
?
To assess the selectivity of L as a fluorescent chemosensor for Cr , the initial
studies included the evaluation of the complexation reactions between L and a
series of metal ions. These spectrofluorometric studies were conducted by titrating
-
6
9
microliter volumes of of 1.0 9 10 mol/L solutions of metal ions (i.e. K , Mg
0:10 (%v/v) MeCN–H O solutions of L (5.0 9 10 mol/L) at 25.0 ± 0.1 °C with
2
-4 ? 2?
,
Al and Ce ), while the absorption of the
2
Hg , Cd , Co , Cr , Zn
?
2?
2?
3?
2?,
3?
3?
L solution was spectrofluorometrically monitored at kex = 553 nm with the ionic
strength of the solution fixed using a 0.01 M ammonium nitrate solution in
2
5.0 ± 0.1 °C.
The results for the tested ions are illustrated in Fig. 3, based on which it can be
3
clearly concluded that only in the case of Cr is a significant increase in the
?
fluorescence intensity of L observed, while other rather abundant metal ions like
2
?
2?
Cd , Hg etc. did not lead to considerable intensity increases. Actually, in the
case of most of the other metal ions tested, the emission intensity remained constant
3
?
2?
3?
or was quenched. Al , Co and Ce , as exceptions to this rule, led to slight
3
?
increases in the intensity. In the case of Cr , the considerable elevation in the
intensity of the fluorescence signal of L was attributed to the strong interactions
between the cation and L.
Figure 4 illustrates that, upon addition of L, the quantity of metal ions increased,
and then they begin to level off and go up again at a metal/ligand ion molar ratio of
1
increase in fluorescence intensity of L as the result of the addition of Cr and based
. The experimental data illustrated in this figure also supports the significant
?
3
1
23

A selective colorimetric and fluorescence chemosensing…
6
5
4
3
2
1
00
00
00
00
00
00
0
3
+
Cr
3
+
Ce
2
+
Co
3
+
2+,
2+
2+
2+
Al ,Cd Zn , Ni , Mg
,
2
+
Hg , L
5
40
560
580
600
620
640
660
680
700
Wavelength(nm)
-
5
-3
Fig. 3 Changes in the emisson spectra of L (5 9 10 M) upon addition of metal ions (5 9 10 mol/L)
in MeCN/H O (90:10,% v/v)
2
5
4
4
3
3
2
2
1
1
00
50
00
50
00
50
00
50
00
Cr
Cd
K
Zn
Ni
Co
Ce
Al
Mg
Hg
5
0
0
0
0.5
1
1.5
2
[
Mn+]/[L]
n?
Fig. 4 Fluorescence intensity versus [M ]/[L] mole ratio plots in AN solution for different transition
metal ions
123

M. Hosseini et al.
on the unanticipated appearance of an emission band for the complexed L, as
compared to the free L (Fig. 4).
The sharp inflection point at a 1:1 molar ratio can be held as valid evidence that,
n?
in all cases, a 1:1 [ML] complex is formed between the metallic cations and the
L in the (90:10, %v/v) MeCN–H O solutions. Furthermore, the formation constants
2
(
Kf) values for each complex were evaluated through fitting the fluorescence
intensity–metal ion molar ratio data to a 1:1 model. To do this, a nonlinear least-
squares curve-fitting program was used [31], and the acquired results are given in
Table 1. Although at such different experimental conditions a different trend was
3
?
observed for fluorescence changes, it could be concluded that [CrL] is the most
stable complex which formed.
Many rohodamine derivatives have been reported to be colorless and non-
fluorescent substances, owing to their stable spirolactam conformations [32, 33],
which was the case with L in this study. However, it is also known that the
disentanglement of this form leads to noticeably altered spectral characteristics.
3
?
Based on our speculations, the addition of Cr to the solution led to the same
disentanglement phenomenon and the formation of a highly delocalized G–
conjugated L structure, enhancing the fluorescence at 556 nm. [21, 32].
The results in Figs. 4 and 5 also revealed a linear correlation between the
3
fluorescence emission intensity of L and the concentration of Cr in the range of
?
-
.0 9 10 to 1.8 9 10 mol/L, with a detection limit of 7.5 9 10 mol/L based
7
-5
-8
1
on 3d of the blank according to the definition by IUPAC.
Selectivity
Since the selectivity behavior can be regarded as the most critical characteristics of
a chemosensor, this was also studied. Selectivity, defined as the relative response
toward the primary ion over other ions present in solution, was evaluated based on
the affinity of L towards other metal cations through the study of the effect of
different metal cations on the fluorescence behavior of L (Fig. 6). The results
showed no observable changes in the fluorescence intensity ratio even when twice
the equivalent amounts of the other metal ions were used.
Table 1 The formation
n?
constants of L - M
Cation
Log Kf
complexes
3
?
Ce
Cd
Hg
4.25 ± 0.11
2.35 ± 0.11
\ 2.0
2
?
2
?
2
Co
?
3.95 ± 0.11
3.00 ± 0.11
3.25 ± 0.12
6.86 ± 0.13
\ 2.0
2?
Ni
2?
Zn
3?
Cr
2
?
Mg
?
K
\ 2.0
3?
Al
3.58 ± 0.17
1
23

A selective colorimetric and fluorescence chemosensing…
a) 1200
(
1000
8
6
4
2
00
00
00
00
0
1
7
0
540
560
580
600
620
640
660
680
700
Wavelength(nm)
b) 1200
(
1000
8
00
00
00
00
0
6
4
2
0
5
10
15
20
25
30
-
6
3+
×
10 MCr
-
5
2
Fig. 5 a Fluorescence titration of L (1 9 10 mol/L) in MeCN/H O (90:10, % v/v). Solution in the
3
?
-7
presence of varying concentrations of Cr ion: (1) 0,(2) 1.0 9 10 mol/L, (3) 5.0 9 10 mol/L, (4)
-7
-
.3 9 10 mol/L, (5) 1.6 9 10 mol/L, (6) 2.6 9 10 mol/L, (7) 3.6 9 10 mol/L, (8)
7
-6
-6
-6
8
4
8
1
-
6
.6 9 10 mol/L, (9) 5.6 9 10 mol/L, (10) 6.6 9 10 mol/L, (11) 7.6 9 10 mol/L, (12)
-6
-6
-6
-
.6 9 10 mol/L, (13) 1.0 9 10 mol/L, (14) 1.1 9 10 mol/L, (15) 1.4 9 10 mol/L, (16)
6
-5
-5
-5
-
5
-5
.8 9 10 mol/L, (17) 2.5 9 10 mol/L kex = 553 nm. b Plot of fluorescence intensity versus of
concentration of Cr in MeCN/H O (90:10, %v/v) solution
2
3
?
123

M. Hosseini et al.
6
00
00
00
00
00
5
B
4
A
Fluorescence
Intensity(A.U)
3
2
1
00
0
S1
-6
Fig. 6 a (gray) Fluorescence responses of L (3 ml 5 9 10 mol/L) upon addition of cations
-
6
(
50 m mol/L) (kex: 553 nm) and b (black) fluorescence responses of L (3 ml 15 9 10 mol/L)
3?
containing 30 mmol/L Cr and the background cations (30 mmol/L) (kex: 553 nm)
Furthermore, the applicability of L as a suitable agent for the construction of a
3
Cr -selective fluorescent chemosensor was studied through competition experi-
?
3
?
ments through mixing 20 lmol/L of Cr with 20 lmol/L of background metal
cations (i.e. alkali, alkali earth, transition and heavy metal ions). The results, in
terms of the fluorescence intensity of solutions containing both background species,
3
?
other cations and Cr , revealed no noticeable differences compared with solutions
3?
3
merely containing Cr , except for Ce
?
2?
and Co . Since there was a slight
fluorescence enhancement before, we can see a synergic effect upon the addition of
Cr3? and additional increase of fluorescence intensity which is in agreement with
previous experiments.
Analytical applications
Finally, the proposed fluorescent sensor was used for the determination of traces of
3
?
Cr ions in spiked water samples. According to the procedure, 10.0 mL of each
water sample (tap and river water samples, Tehran, Iran) was taken and diluted in a
3
?
2
5.0-mL volumetric flask using distilled water. Then, various quantities of Cr
-
5.0 9 10 , 1.0 9 10 mol/L) were added to the samples, and the proposed
7
-6
(
3
?
chemosensor was applied to determine the Cr content using a calibration method.
The results, summarized in Table 2, clearly prove that the chemosensor can be used
3
for the determination of Cr in different aqueous samples.
?
1
23

A selective colorimetric and fluorescence chemosensing…
3?
Table 2 Determination of Cr ions in water samples and wastewater with the proposed sensor
a
Found (ppm)
Sample
Added (ppm)
Relative error (%)
-7
-6
-7
-6
-7
-6
-7
-6
Wastewater
5.0 9 10
.0 9 10
5.0 9 10
.0 9 10
(5.4a ± 0.1) 9 10
(0.95 ± 0.2) 9 10
(5.30 ± 0.05) 9 10
(1.08 ± 0.1) 9 10
8.0
5.0
6.0
8.0
1
River water
1
a
Results are based on three measurements
Conclusion
3
?
In conclusion, a novel enhancement fluorescent chemosensor, L, for Cr
MeCN/H O (90:10, %v/v) solution was synthesized and investigated. It showed a
in
(
selective and sensitive fluorescence response to Cr in (MeCN/H O (90:10, %v/v)
2
3
?
2
solution. The fluorescence enhancing of L is attributed to the 1:1 complex formation
3
between L and Cr which has been utilized as the basis for the selective detection
?
3
of Cr . Receptor L exhibits enhanced fluorescent probe results along a wide
?
3
concentration range of Cr with no interference of background cations.
?
Acknowledgements The authors thank the research Council of University of Tehran (Grant 28645/01/
02) for financial support of this work.
References
1
. R. Mcrae, P. Baqchi, S. Sumalekshmy, C.J. Fahrni, Chem. Rev. 109, 4780 (2009)
. C. Cervantes, J. Campos-Garc ´ı a, S. Devars, F. Guti e´ rrez-Corona, H. Loza- Tavera, J.C. Torres-
Guzm a´ n, R. Moreno-S a´ nchez, FEMS Microbiol. Rev. 25, 335 (2001)
2
3. M. Hosseini, M. Aghazadeh, M.R. Ganjali, New J. Chem. 41, 12678 (2017)
4. M. Dadmehr, M. Hosseini, S. Hosseinkhani, M.R. Ganjali, R. Sheikhnejad, Biosens. Bioelectron. 73,
108 (2015)
5. M.R. Ganjali, M. Hosseini, M. Motalebi, M. Sedaghat, F. Mizani, F. Faridbod, P. Norouzi, Spec-
trochim. Acta Part A 140, 283 (2015)
6. M. Hosseini, A. Ghafarloo, M.R. Ganjali, F. Faridbod, P. Norouzi, M. SalavatiNiasari, Sens.
Actuators B 198, 411 (2014)
7. J. Mao, Q. He, W.S. Liu, Anal. Bioanal. Chem. 396, 1197 (2010)
8. Y. Wan, Q.J. Guo, X.F. Wang, A.D. Xia, Anal. Chim. Acta 665, 215 (2010)
9. D.P. Wang, Y. Shiraishi, T. Hirai, Tetrahedron Lett. 51, 2545 (2010)
10. Z.X. Li, W.Y. Zhao, Y.N. Zhang, L.F. Zhang, M.M. Yu, J.X. Liu, H. Zhang, Tetrahedron 67, 7096
(2011)
1
1. J.Y. Jung, S.J. Han, J. Chun, C. Lee, J. Yoon, Dye Pigment 94, 423 (2012)
2. S. Guha, S. Lohar, A. Banerjee, A. Sahana, I. Hauli, S.K. Mukherjee, J.S. Matalobosc, D. Dasa,
Talanta 91, 18 (2012)
1
13. P. Saluja, H. Sharma, N. Kaur, N. Singh, D.O. Jang, Tetrahedron 68, 2289 (2012)
14. Y. Zhou, J. Zhang, L. Zhang, Q. Zhang, T. Ma, J. Niu, Dye Pigment 97, 148 (2013)
15. B. Tang, T. Yue, J. Wu, Y. Dong, Y. Ding, H. Wang, Talanta 64, 955 (2004)
16. J.H. Chang, Y.M. Choi, Y.K. Shin, Bull. Korean Chem. Soc. 22, 527 (2001)
17. M. Sarkar, S. Banthia, A. Samanta, Tetrahedron Lett. 47, 7575 (2006)
18. B. Valeur, Molecular Fluorescence: Principles and Applications (Wiley, New York, 2001), p. 273
19. D. Liu, T. Pang, K. Ma, W. Jiang, X. Bao, RSC Adv. 4, 2563 (2014)
123

M. Hosseini et al.
2
2
2
2
0. H. Liu, X. Wan, T. Liu, Y. Li, Y. Yao, Sens. Actuators B 200, 191 (2014)
1. J. Mao, Q. He, W. Liu, Anal. Bioanal. Chem. 396, 1197 (2010)
2. M.R. Ganjali, M. Hosseini, M. Hariri, F. Faridbod, P. Norouzi, Sens. Actuators B 142, 90 (2009)
3. M. Hosseini, M.R. Ganjali, B. Veismohammadi, F. Faridbod, P. Norouzi, S. Dehghan Abkenar, Sens.
Actuators B 147, 23 (2010)
2
2
2
2
4. M. Hosseini, Z. Vaezi, M.R. Ganjali, F. Faridbod, S.D. Abkenar, K. Alizadeh, M. Salavati-Niasari,
Spectrochim. Acta A 75, 978 (2010)
5. M. Hosseini, M.R. Ganjali, B. Veismohammadi, P. Norouzi, K. Alizadeh, S. Dehghan, Abkenar.
Mater. Sci. Eng. C 30, 929 (2010)
6. M. Hosseini, M.R. Ganjali, F. Aboufazeli, F. Faridbod, H. Goldooz, A. Badiei, P. Norouzi, Sens.
Actuators B 184, 93 (2013)
7. M. Hosseini, M.R. Ganjali, Z. Vaezi, B. Arabsorkhi, M. Dadmehr, F. Faridbod, P. Norouzi, Sens.
Actuators B 210, 349 (2015)
2
2
3
3
3
8. M.R. Ganjali, B. Veismohammadi, M. Hosseini, P. Norouzi, Spectrochim. Acta A 74, 575 (2009)
9. N.R. Chereddy, S. Thennarasu, Dye Pigment 91, 378 (2011)
0. X. Zhou, X.B. Wang, T. Wang, L.Y. Kong, Bioorg. Med. Chem. 16, 8011 (2008)
1. J.L. Dye, V.A. Nicely, J. Chem. Educ. 48, 443 (1971)
2. J.Y. Kwon, Y.J. Jang, Y.J. Lee, K.M. Kim, M.S. Seo, W. Nam, J. Yoon, J. Am. Chem. Soc. 127,
10107 (2005)
33. V. Dujols, F. Ford, A.W. Czarnik, J. Am. Chem. Soc. 119, 7386 (1997)
1
23