Fast and sensitive fluorescent detection of inorganic mercury species and methylmercury using a fluorescent probe based on the displacement reaction of arylboronic acid with the mercury species

Article abstract of DOI:10.1039/c9cc09240d

We present a reaction-based fluorescent probe (1) for Hg²⁺ and CH₃Hg⁺, based on the displacement reaction of the arylboronic acid with the mercury species. 1 showed promising sensing properties for Hg²⁺ and CH₃Hg⁺, such as high selectivity and sensitivity, turn-on response, fast response to Hg²⁺ (<2 min) and CH₃Hg⁺ (<5 min), low detection limits and operation in purely aqueous solutions.

Full text of DOI:10.1039/c9cc09240d

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Conformational control of nonplanar free base porphyrins:
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Fast and sensitive fluorescent detection of inorganic mercury species
and methylmercury using fluorescent probe based on displacement
reaction of arylboronic acid with the mercury species
5 Lok Nath Neupanea, Joohee Parka, Pramod Kumar Mehtaa, Eun-Taex Ohb, Heon Joo Parkb and Keun-
Hyeung Leea,*
15 Receipt/Acceptance Data [DO NOT ALTER/DELETE THIS TEXT]
Publication data [DO NOT ALTER/DELETE THIS TEXT]
DOI: 10.1039/b000000x [DO NOT ALTER/DELETE THIS TEXT]
We presented a reaction-based fluorescent probe (1) for Hg2+ ions as
well as methylmercury, based on the displacement reaction of the
arylboronic acid with the mercury species. 1 showed promising
sensing properties for Hg2+ and methylmercury, such as high
selectivity and sensitivity, turn-on response, fast response to Hg2+ (<
2 mins) and methylmercury (< 5 mins), low detection limits and
operation in purely aqueous solutions.
sensitive detection of inorganic mercury species as well as
methylmercury species.
We have focused on the displacement reaction of arylboronic
acid with mercury species for the development of new reaction-
based fluorescent probes for Hg2+ and methylmercury as
following reasons (Scheme 1). Phenylboronic acid derivatives
reacted with inorganic mercury salts and arylmercury halides in
glacial acetic acid medium to provide corresponding
phenylmercury chlorides and diarylmercury, quantitatively.9
Quantification of Hg2+ in natural waters using GC analysis has
used the selective irreversible reaction of phenylboronic acid with
Hg2+ in acidic condition.10 The displacement reaction of
arylboronic acids with mercury species unlike Hg2+ ion-promoted
desulfurization reactions provided a covalent adduct of the probe
with mercury species (Scheme 1). Furthermore, the covalent
adduct of the probe produced in the real time monitoring in the
field could be reanalyzed to confirm the concentrations of
mercury species by current common analytical methods.
Among various toxic molecules, inorganic and organic
mercury species have been regarded as the most toxic molecules.
Specially, methylmercury species (CH3HgX; X = halides) were
much more toxic than inorganic mercury species because
methylmercury species penetrated readily lipid membranes of
cells and accumulated easily in organs such as brain, kidneys,
and endocrine system, resulting in sever toxicities to human
body.1-3 The contamination of inorganic mercury species in
natural waters has been increased by human activities, such as
gold mining and coal power plants.1,2 The increase of
methylmercury species, converted from inorganic mercury
species by aquatic microorganisms was also a matter of
significant concern worldwide.1 Thus, it was highly demanded for
the sensitive, selective, and fast detection methods for inorganic
mercury species as well as methylmercury species in environment.
Atomic absorption spectrometry, cold vapor atomic
fluorescence spectrometry, and inductively coupled plasma-mass
spectrometry (ICP-MS) have been widely employed to detect
inorganic and organic mercury species owing to their high
sensitivity. On the other hand, these techniques required
complicated sample preparation, time consuming procedures, and
expensive instruments.4,5 Alternatively, fluorescent techniques for
detecting mercury species have received attentions due to high
sensitivity, simplicity, low cost, and real-time monitoring.
Various types of reaction-based fluorescent probes for inorganic
mercury species (Hg2+ ions) have been synthesized based on Hg2+
ion-promoted specific reactions.6,7 There was a significant
progress of fluorescent probes for Hg2+ ions.6,7 On the other hand,
only several reaction-based fluorescent probes for methylmercury
have been reported.8 As methylmercury (CH3Hg+) was less
thiophilic and less charged than Hg2+, the known reaction-based
probes that sensed methylmercury showed either slower response
or required larger amounts of mercury species for signal
saturation (Table S1).8 Thus, it was highly demanded for the
development of new reaction-based fluorescent probe for fast and
N
N
O
S N
O
O
S N
O
OH
H
H
B
OH
1
2
CH3Hg+
N
O
S N
O
1
H
Hg
CH3
Hg2+
3
N
N
N
1
O
S N
O
O
N S
O
O
S N
O
H
H
H
Hg+
Hg
4
Scheme 1. Structures of 1 and 2 and a product of the reaction of 1 with
Hg2+ and methylmercury (CH3Hg+).
Even though the application of the displacement reaction of
arylboronic acid with mercury species into fluorescent probes has
great potential, it was highly challenging for the synthesis of
reaction-based fluorescent probes based on the displacement
reaction of arylboronic acid with mercury species. First of all,
mercuration of the fluorophore part of the probe must result in the
significant decrease of the emissions due to potent quenching
effect of the proximate mercury atom.11,12 Turn-off response of
fluorescent probes was not recommended because the decrease of
the emissions of fluorescent probes could be induced by other
external factors such as precipitation of the probe and absorbance
of some impurities. Second, the mercuration of arylboronic acids
was an electrophilic substitution reaction; the reaction was not
fast and quantitative without acids.9 Up to now, there were a few
examples for the fluorescent detection methods for Hg2+ ions
based on a catalytic antibody with arylboronic acid, quantum dots
aDepartment of Chemistry and Chemical engineering, Inha University
bDepartment of Biomedical Sciences, College of Medicine, Inha
University, Inha-Ro 100, Incheon city, 402-751,South Korea
Fax- 82-32-8675604, Tel. 82-32-8607674 E-mail: leekh@inha.ac.kr
Electronic Supplementary Information (ESI) available: synthesis scheme,
additional fluorescence spectra,1H NMR data, and ESI-MS data.
See http://dx.doi.org/10.1039/b000000x/
This journal is © The Royal Society of Chemistry [year]
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A fluorescent titration of 1 with Hg2+ was also conducted in
aqueous buffered solution (10 mM HEPES, pH 7.4) including 1%
CH3CN (Figure 1). Addition of Hg2+ ions induced instantaneous
enhancement of the emissions. Even low equivalents (< 0.3
equiv.) of Hg2+ ions completed the enhancement of the emissions
within 2~3 mins. As the concentration of Hg2+ increased, the
emission at 500 nm undergoes a ca. 16-fold increase and the
emission maxima shifted from 535 nm to 500 nm. The probe
showed saturation of fluorescent change about at 0.6 equiv. of
Hg2+ ions, which could be explained by the mechanism study.
When we investigated the fluorescent response of 1 to a different
inorganic mercury salts, such as Hg(NO3)2, Hg(ClO4)2 and
Hg(OAc)2, similar fluorescent spectra and very fast response
times (< 2 mins) were obtained (Figure S10). This revealed that
the counter-anions have a negligible effect on the florescent
detection and response time for inorganic mercury species.
functionalized with phenylboronic acid, and a simple pyrene
boronic acid.13-15 These fluorescent methods detected only Hg2+
ions (not methylmercury) by turn-off responses due to quenching
effect of the proximate mercury atom.13 These methods required
long incubation times (10~30 mins) for the complete of the
fluorescent change induced by Hg2+.
In the present study, we synthesized
a reaction-based
fluorescent probe (1) for inorganic mercury species as well as
methylmercury based on the displacement reaction of arylboronic
acid for the mercury species. 1 showed promising sensing
properties for Hg2+ and methylmercury, such as high selectivity
and sensitivity, turn on response (ca. 20-fold enhancement), fast
responses, operations in purely aqueous solutions, and low
detection limits, which made it possible for the real time
monitoring for the mercury species in the field. The mechanism
study using HPLC-mass spectrometer and NMR revealed that the
displacement reaction of the arylboronic acid part of 1 with
mercury species was a key reaction for the detection of the
mercury species. According to the results of the previously
reported chemosensors, the chelation of Hg2+ with sulfonamide
groups might induce the deprotonation of NH of the
sulfonamides.16 Thus, we synthesized fluorescent probe (1) in
To confirm the role of the boronic acid of 1, we synthesized 2
without a boronic acid group and measured fluorescent response
of 2 to Hg2+ ions (Figure S11). Upon addition of Hg2+, the
fluorescent emissions of 2 decreased slightly due to the
quenching effect of Hg2+ ions, which confirmed the critical role
of the boronic acid of 1 for the detection of Hg2+ ions.
which
a
dansyl fluorophore was conjugated with the
phenylboronic acid via a sulfonamide group as a reversible ligand
for the mercury species because the deprotonation of the
sulfonamide group by mercury species might cause the increase
of the electron density of arylboronic moiety, resulting in the fast
reaction. Furthermore, we designed the probe in which the
boronic acid moiety was located away from the fluorophore part
to minimize the quenching effect of mercury. 1 was prepared in
high yield (80%) using a two-step procedure (Scheme S1). 1 and
2 without a boronic group were characterized by HPLC, mass
spectrometer, and NMR (Scheme 1, Figure S1-S9).
240
1
1 + Hg(II)
1 + Hg(II) + Metal ions
2+
250
200
150
100
50
(a)
Hg
(b)
200
160
120
80
40
None and other metal ions
0
A solution of 1 in distilled water containing 1% CH3CN
0
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
I
I
(
400
450
500
550
600
650
700
e
b
H
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
(
I I
I I
I
(
e
B
-
(
I
(
I
I
I
(
I
I
(
I
(
I
(
(
(
I
(
(
i
N
M
(
(
(
(
a
(
l
g
K
o
r
g
g
a
o
n
u
n d
C
b
e
F
F
a
r
N
A
C
A
C
C
Z
P
M
C
Wavelength (nm)
P
exhibited
a weak fluorescence centered at 550 nm. A
(c)
fluorescence titration of 1 with Hg2+ was conducted in distilled
water containing 1% CH3CN (Figure 1). As the concentration of
Hg2+ increased, the emission at 500 nm undergoes a ca. 20-fold
increase and the emission maxima shifted from 550 nm to 500
nm. Hg2+ ions induced the significant enhancement of the
emissions within 6 min and approximately 0.6 equiv. of Hg2+ was
necessary for the saturation of the emission change.
Ca2+ Hg2+
Na+ Mg2+
Co2+
Al3+
Cr3+
Ni2+
Mn2+ Cu2+ Zn2+ Cd2+ Ag+ Pb2+
1
Fig. 2 (a) Fluorescent spectra of 1 (10 µM) with metal ions (1.0 equiv.)
and (b) Emission intensity of 1 (10 µM) with Hg2+ (1.0 equiv.) and
additional metal ion (1.0 equiv.) (c) Visible emission color images under
UV-light (λex = 365 nm) in aqueous buffered solution (10 mM HEPES) at
pH 7.4 containing 1% CH3CN.
200
200
200
(a)
160
120
160
160
120
80
40
0
80
40
0
We evaluated the fluorescent response of 1 to other metal
species (Na+, Mg2+, Ca2+, Al3+, Hg2+, Cr3+, Co2+, Ni2+, Mn2+,
Cu2+, Zn2+, Cd2+, Ag+, Pb2+, K+) in aqueous buffered solution
(10 mM HEPES, pH 7.4) containing 1% CH3CN (Figure 2). 1
exhibited a highly selective turn on response to Hg2+ among
various metal ions. Furthermore, we measured the enhancement
of the emissions of 1 by Hg2+ ions in the presence of the other
metal ions. 1 exhibited similar enhancements of the emissions by
Hg2+, even in the presence of other metal ions. This result
supported that 1 exhibited highly selective response to Hg2+ in
purely aqueous solutions. The selective visible emission color
images of 1 induced by Hg2+ ions was observed by naked eyes
under UV light (Figure 2c). The visible emission color image of 1
was not changed by other metal ions but changed by Hg2+ from
pale yellow color to bright cyan color. This indicated that rapid
naked-eye detection of Hg2+ could be possible using the probe
with a UV lamp.
120
80
40
0
0
1
2
3
4
]
5
M
6
7
[HgCl
2
0
100
200
Time (sec)
300
400
400
450
500
550
600
650
700
Wavelength (nm)
250
200
150
100
50
250
200
150
100
50
200
150
100
50
(b)
0
0
1
2
3
]
4
M
5
6
7
[HgCl2
0
400
0
450
500
550
600
650
700
0
50
100
150
Time (s)
200
250
300
Wavelength (nm)
Fig. 1 Fluorescent spectrum and time-dependent emission intensity at 500
nm of 1 (10 µM) with Hg2+ (0-0.7 equiv.) in (a) water-CH3CN (99/1, v/v)
and (b) aqueous buffered solution (10 mM HEPES, pH 7.4) containing
1% CH3CN (λex = 380 nm).
The detection limit of 1 for Hg2+ was measured on the basis of
the linear relationship between the emission intensity at 500 nm
and the concentration of Hg2+ (Figure S12). The emission
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the absorption spectra was observed at basic pHs (pH > 8),
whereas a red-shift in the absorption spectra was observed at
acidic pHs (pH < 7). The charge of the boronic group of 1 might
play an important role for the change of the electron density of
the dansyl fluorophore moiety of 1. UV-visible titration 1 (10
µM) with Hg2+ was carried out (Figure S17). Upon addition of
Hg2+, the absorbance at 330 nm corresponding to the dansyl
fluorophore increased and red-shifted simultaneously. The
fluorescence quantum yield (ɸF = 0.045) of 1 was increased to
0.18 with Hg2+ (anthracene as a reference).17 As we expected,
Hg2+ chelation with the sulfonamide group of 1 might induce the
deprotonation of NH of the sulfonamide, which improved the
reactivity of the displacement reaction between 1 and Hg2+. We
suggested the enhancement of the emission of 1 by reaction with
Hg2+ based on the results. 1 was converted into the diarylmercury
compound (4) by the reaction with Hg2+. The mercury of 4 might
enhance electron-withdrawing effect on the dansyl moiety,
resulting in the red-shift of the absorbacne at 330 nm and increase
of the emissions. We measured the absorption/emission band
shifts of 4 depending on solvents of different polarity ranging
from toluene to DMSO (Table S2). The emission maximum of 4
was slightly red-shifted in more polar solvent, which supported
that the exchange of the boronic acid to Hg2+ might enhance the
intramolecular charge-transfer in the molecule.
intensity at 500 nm was proportion to the amount (0~200 nM) of
Hg2+ that we added. The detection limit for Hg2+ was calculated
to be 4.02 nM (0.80 ppb, R2 = 0.923) in distilled water and 1.82
nM (0.36 ppb, R2 = 0.996) in aqueous buffered solution (10 mM
HEPES, pH 7.4), respectively. The detection limits were lower
than the maximum allowable level of mercury ions in drinking
water (10 nM, 2 ppb) by EPA.
mV
bar
4000
3750
3500
3250
3000
2750
2500
2250
2000
1750
1500
1250
1000
750
950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
N
(a)
O
S
O
OH
H
N
B
OH
1
500
250
0
0
0.0
mV
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
25.0
27.5
30.0
32.5
35.0
37.5
40.0
42.5
45.0
47.5
50.0
52.5
55.0
57.5
60.0 min
bar
1900
1800
950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
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150
100
50
N
N
1700 (b)
O
S
O
O
S
O
H
N
H
N
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
Hg
4
0
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
25.0
27.5
30.0
32.5
35.0
37.5
40.0
42.5
45.0
47.5
50.0
52.5
55.0
57.5
60.0 min
Fig. 3 HPLC analysis using C18 column of (a) 1 and (b) 1 with Hg2+ (0.5
equiv.) in distilled water containing 1% CH3CN. Black line and red line
indicated the absorbance at 214 nm and 280 nm, respectively.
A fluorescent titration of 1 (10 µM) with methylmercury
(CH3Hg+) was conducted in aqueous buffered solution (10 mM
HEPES) at pH 7.4 including 1% CH3CN (Figure 4). Addition of
methylmercury induced the significant enhancement of the
emissions within 6 mins. Interestingly, 1 exhibited a saturation of
fluorescent change about at 1.0 equiv. of methylmercury. The
fluorescence quantum yield (ɸF = 0.042) of 1 was increased to
0.35 with methylmercury (anthracene as a reference).17 1 showed
higher reactivity for methylmercury than those of the other
reported fluorescent probes for methylmercury (Table S1). For
example, 1 equiv. of methylmercury induced the saturation of the
emission intensity change (ca. 23-fold) of 1 within 6 mins,
whereas the other reaction-based fluorescent probes required
larger amounts of methylmercury and longer reaction times for
the complete of the emission intensity change (Table S1).8
To investigate the irreversible reaction of 1 with Hg2+, we
incubated 1 with Hg2+ for 10 mins. And then we added EDTA as
a chelating agent into the solution and measured the spectrum of
the resulting solution. The fluorescent spectrum of 1 with Hg2+
was not changed by addition of EDTA (Figure S13), which
support that 1 might detect Hg2+ irreversibly. We further analyzed
the product of 1 with Hg2+ using HPLC-MS (high performed
liquid chromatography-mass spectrometer). For this, we
incubated 1 with Hg2+ in distilled water containing 1 % CH3CN
and then analyzed the product(s) using HPLC-MS with C18
column (Figure 3). A new peak at longer retention time than that
of
1 appeared in HPLC, which suggested that a more
500
hydrophobic compound than 1 was synthesized by the reaction of
1 with Hg2+. Mass spectrum of the major peak at 52 min indicated
that 1 was reacted with Hg2+ to yield a diarylmercury compound
(4) because the measured molecular weight of 853.12 (m/z)
corresponded to 4 + H+ (Figure S14). As shown in Scheme 1, 1
reacted with Hg2+, resulting in the synthesis of the arylmercury
compound, and then the arylmercury compound reacted with 1,
resulting in the synthesis of 4. It was reported that
diphenylmercury and asymmetrical diarylmercury were prepared
by reaction of arylmercury halides with arylboronic acids.9
Overall results revealed that 1 detected Hg2+ irreversibly through
the displacement reaction of the arylboronic acid moiety with
Hg2+ and the final product of this reaction was a diarylmercury
compound (4). This result could explain the reason why 1
exhibited a saturation of fluorescent change about at 0.6 equiv. of
Hg2+ and suggested that the probe could detect methylmercury.
500
(a)
500
400
300
200
100
0
(b)
400
300
200
100
0
400
300
200
100
0
0
2
4
6
8
10
[MeHgCl] M
0
100
200
300
400
400
450
500
550
600
650
700
Wavelength (nm)
Time (sec)
1
60 (c)
+1uM MeHgCl
+2uM MeHgCl
+3uM MeHgCl
+4uM MeHgCl
+5uM MeHgCl
+6uM MeHgCl
+7uM MeHgCl
+8uM MeHgCl
+9uM MeHgCl
+10uM MeHgCl
+11uM MeHgCl
+12uM MeHgCl
60 (d)
50
40
30
20
10
50
40
30
20
10
0
0
400
2
4
6
8
10
12
450
500
550
600
650
700
1H NMR experiments for the reaction of 1 with Hg2+ were
carried out in DMSO-d6 (Figure S15). A significant down-field
shift of the peaks at 7.51 and 7.43 ppm corresponding to the
protons in the phenylboronic moiety in the presence of Hg2+
confirmed that the boronic group of 1 was substituted by Hg2+.
The down-field shift of the peak at 10.7 ppm, corresponding to
the NH peak of the sulfonamide group suggested that the
sulfonamide group of 4 might interact with the mercury moiety of
[ CH3HgCl ] (M)
Wavelength (nm)
Fig. 4 (a) Fluorescent spectrum and (b) time-dependent emission intensity
of 1 (10 µM) with CH3HgCl(0-1.0 equiv.), (c) fluorescent spectrum and
(d) emission intensity change of 1 (5 µM) versus the concentration of
CH3HgCl (0-1.0 equiv.) in aqueous buffered solution (10 mM HEPES,
pH 7.4) containing 1% CH3CN. The emission intensity was acquired 5
mins after addition of CH3HgCl (λex = 380 nm).
4
or free Hg2+ ions. We measured pH-dependent
Even though 1 showed fast and sensitive responses to
methylmercury in purely aqueous solutions, low amounts (0~0.3
absorption/emission spectrum of 1 (Figure S16). A blue-shift in
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4
K. A. Anderson, Mercury analysis in environmental samples by cold
vapor techniques, in: Encyclopedia of Analytical Chemistry, Wiley,
New York, 2006.
J. M. Lo, J. C. Yu, F. I. Hutchison, C. M. Wai, Anal. Chem., 1982,
54, 2536.
a) E. M. Nolan and S. J. Lippard, Chem. Rev., 2008, 108, 3443; b) Y.
Yang, Q. Zhao, W. Feng, F. Li, Chem. Rev., 2013, 113, 192; c) H. N.
Kim, W. X. Ren, J. S. Kim, J. Yoon, Chem. Soc. Rev., 2012, 41,
3210.
equiv.) of methylmercury induced a little enhancement of the
emission in this condition. We optimized some conditions (the
concentration probe, pH, slit size, and buffering agents) for the
reactivity of 1 for methylmercury. 1 showed considerable turn-on
response to the low concentrations (0~3 equiv.) of methylmercury
within 5 mins and a linear relationship between the emission
intensity and the concentration of methylmercury was obtained
for a wide concentration ranging from 0 to 8 µM (0~1600 ppb).
The detection limit for methylmercury was below 1 µM (200
ppb). Considering the limits (500-1000 ppb) for organic mercury
species in food,18 1 had an enough sensitivity and fast response
for the detection of contaminated methylmercury in food.
5
6
7
For some examples of Hg2+-selective fluorescent probes, see: a) X.
Zhang, Y. Xiao, X. Qian, Angew. Chem. Int. Ed., 2008, 47, 8025; b) J.
Liu and Y. Lu, Angew. Chem. Int. Ed., 2007, 46, 7587. c) Y. K. Yang, K.
J. Yook, J. Tae, J. Am. Chem. Soc., 2005, 127, 16760; d) I. Samb, J.
Bell, P. Y. Toullec, V. Michelet, I. Leray, Org. Lett., 2011, 13, 1182; e)
S. Ando and K. Koide, J. Am. Chem. Soc., 2011, 133, 2556; f) M. H.
Lee, S. W. Lee, S. H. Kim, C. Kang, J. S. Kim, Org. Lett., 2009, 11,
2101; g) Z. Ruan, C. Li, J. R. Li, J. Qin, Z. Li, Sci. Rep., 2015, 5, 15987;
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To confirm the irreversible reaction between
1
and
methylmercury, we analyzed the product(s) of 1 with CH3HgCl
using HPLC-mass spectrometer with C18 column. In this case, we
used distilled water including 2% CH3CN as a solvent for the
convenience purification. According to HPLC-MS analysis, the
peak corresponding to 1 disappeared and new major peak
corresponding to arylmethylmercury at 542.10 (m/z) was
observed (Figure S18-S19). This result suggested that 1 reacted
irreversibly with CH3Hg+, resulting in the production of
arylmethyl mercury compound (3). The product could explain the
reason why 1 exhibited a saturation of fluorescent change about
at 1.0 equiv. of CH3HgCl. We measured the absorption/emission
band shifts of 3 depending on solvents of different polarity (Table
S2). The emission maximum of 3 was slightly red-shifted in more
polar solvent, which supported that the exchange of the boronic
acid to methylmercury might enhance the intramolecular charge-
transfer in the molecule.
The potential application in intracellular detection of Hg2+ and
CH3Hg+ using the fluorescent probe was studied (Figure S20).
The probe penetrated biological membranes of the cells and
detected intracellular Hg2+ and CH3Hg+ by turn-on response,
which supported that the displacement reaction of the arylboronic
acid with mercury species worked well in the cellular
environment and the reaction-based probe could be applied for
probing the mercury species in cells.
In the present study, we showed that the displacement reaction
of arylboronic acid with mercury species was very useful for the
development of novel fluorescent probes for inorganic mercury
species as well as methylmercury. The fluorescent probe based on
the displacement reaction of arylboronic acid with mercury
species showed remarkable sensing properties for Hg2+ as well as
methylmercury such as high sensitivity, high selectivity, fast
response at room temperature, operations in purely aqueous
solutions, and large fluorescent signal change. Unlike the other
reaction-based probes for Hg2+ and methylmercury, 1 detected
Hg2+ as well as methylmercury by formation of a covalent adduct
of the probe with the mercury species. Considering the recent
increase of contamination of inorganic and organic mercury
species, this result will promote to develop new sensing and
removing systems for inorganic and organic mercury species
based on the displacement reaction of arylboronic acid
derivatives.
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This work was supported by the Inha University Research Grant.
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