Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
Supporting Information for
A Colorimetric Probe for the Selective Naked-Eye Detection of Pb(II) Ions in
Aqueous Media
Jihye Park and Youngmi Kim*
Department of Chemistry, Dankook University, 126 Jukjeon-dong, Yongin-si, Gyeonggi-do, 448-701, Korea
[email protected]
Tel: +82 31-8005-3156
Fax: +82 31-8005-3148
1. Materials and Methods
Compounds 1,1 2,2 and 31 were obtained according to the literature procedure. Electrospray ionization mass
(ESI-MS) spectra were obtained at national center for inter-university research facilities. Infrared spectra were
obtained using PerkinElmer Spectrum 100FT-IR Spectrometers. All absorption spectra were recorded with a
Shimadzu UV-2501 spectrophotometer. Fluorescence measurements were recorded on a Hitachi F-7000
fluorescence spectrophotometer at 25 °C using 10 mm quartz cuvettes with a path length of 1 cm. Stock
solution of metal nitrate salts (2.04 mM) were prepared in water. Stock solution of probes (0.51 mM) was
prepared in CH3CN. UV/Vis titration experiments were performed using 5 M of probe 1 in CH3CN/HEPES
solution (1/99, v/v) with varying concentrations of the metal nitrate salts.
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Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
2. More Spectroscopy Data
2.5
0 min
3 min
5 min
10 min
20 min
30 min
60 min
90 min
A527/A496
2.0
1.5
1.0
0.5
0
4
8
12
16
20
[Pb2+]/M
Fig. S1 Absorption ratio (A527/A496) of probe 1 (5 M) upon addition of varied concentrations of Pb(NO3)2.
Incubation time = from bottom to top: 0, 3, 5, 10, 20, 30, 60, 90 min. All data were obtained in HEPES buffer
(10 mM, pH 7.4, 1% CH3CN) at 25 oC.
0.35
A527
0.28
0.21
0.14
0.07
0.00
0.0
0.2
0.4
0.6
[1]
2+
[1] + [ Pb ]
0.8
1.0
Fig. S2 Job’s plot of a 1:1 complex of 1 and Pb2+, where the absorbance at 527 nm is plotted against the mole
fraction of 1 at an invariant total concentration of 40 µM in HEPES buffer (10 mM, pH 7.4) containing 1%
CH3CN.
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Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
Fig. S3 ESI-MS spectrum of 1-Pb2+ complex.
100
T (%)
80
60
40
Probe 1
Probe 1 + Pb2+
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm-1)
Fig. S4 Infrared spectra of 1 and 1-Pb(II) adduct.
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Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
3.5
Probe 1
Probe 1 + Pb2+
A527/A496
2.8
2.1
1.4
0.7
0.0
2
3
4
5
6
7
8
9
pH
Fig. S5 Absorption ratio (527 over 496 nm) of 1 (5 µM) and 1 treated with Pb(II) ions (4 equiv.) in different pH
buffer systems containing 1% CH3CN as a cosolvent at 25 oC. Incubation time is 30 min.
0.5
3.5
1 (0.5 M)
1 (1 M)
1 (2 M)
1 (3 M)
1 (4 M)
1 (5 M)
0.3
2.8
A527/A496
Absorbance
0.4
2+
1 (0.5 M) + Pb
2+
1 (1 M) + Pb
2+
1 (2 M) + Pb
0.2
2+
1 (3 M) + Pb
2+
1 (4 M) + Pb
2.1
1.4
2+
1 (5 M) + Pb
0.1
0.0
400
0.7
0.0
450
500
550
600
650
700
0
Wavelength (nm)
1
2
3
[Probe 1] / M
4
5
Fig. S6 Absorption spectra of probe 1 (0.5 - 5 µM) upon addition of corresponding 4 equiv. of Pb2+ in HEPES
buffer (10 mM, pH 7.4, containing 1% acetonitrile) at 25 oC.
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Fluorescence Intensity (a.u.)
Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
200
Probe 1 only
1 + Pb2+ 1.00 M
1 + Pb2+ 2.50 M
1 + Pb2+ 5.00 M
1 + Pb2+ 7.50 M
1 + Pb2+ 10.0 M
1 + Pb2+ 12.5 M
1 + Pb2+ 15.0 M
1 + Pb2+ 20.0 M
1 + Pb2+ 25.0 M
160
120
80
40
0
480
500
520
540
560
580
600
Wavelength (nm)
Fig. S7 Fluorescence emission spectra of 1 (5 µM) in the presence of various concentrations of Pb2+ (Excited at
460 nm). All spectra were taken at 30 min in HEPES buffer (10 mM, pH 7.4, 1% CH3CN) at 25 oC.
Fig. S8 Normalized UV-visible spectra of compounds 1–3 (5 µM) upon addition of 4 equiv. of Pb(NO3)2. All
data were taken at 30 min in HEPES buffer (10 mM, pH 7.4, 1% CH3CN) at 25 °C.
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Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
Fig. S9 Color change of probe 1 in the absence (a) and presence (b) of Pb(NO3)2. Subsequently, either HCl (c)
or EDTA (d) was added to the 1-Pb(II) adduct.
2.5
A527/A496
2.0
1.5
1.0
0.5
0.0
probe Pb(II) Fe(III) Al(III)
Cr(II)
Fe(II) Mn(II) Cd(II) Ag(II)
Na(I) Ca(II)
Ni(II)
Cu(II) Hg(II) Co(II) Mg(II) Zn(II)
Fig. S10 Absorption ratio (527 over 496 nm) of 1 (5 µM) upon addition of different metal ions (4 equiv.) in
HEPES buffer (10 mM, pH 7.4, 1% CH3CN, 25 °C). All data were measured at 30 min after addition of each
metal ion.
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Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
0.30
Absorbance
0.25
Probe 1
other metal ions+ Pb
2+
0.20
2+
Cr + Pb
0.15
2+
2+
Fe + Pb
2+
0.10
0.05
300
400
500
600
700
Wavelength (nm)
Fig. S11 Absorption spectra of probe 1 upon addition of different metal ions (4 equiv.) and subsequent addition
of Pb(II) ions (4 equiv.) to each mixture.
0.4
Abs527
0.2
0.0
5
-0.2
10
15
20
25
30
Pb2+ (M)
-0.4
-0.6
Fig. S12 Absorbance at A527 of probe 1 (5 M) upon addition of varied concentrations of Pb(NO3)2.
Determination of dissociation constant was assessed from titration curve of Pb2+ with probe 1 (5 µM) and
calculated using one-site binding model on GraphPad Prism version 5.
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Electronic Supplementary Material (ESI) for Analyst
This journal is © The Royal Society of Chemistry 2012
0.20
1
1.0
2+
1 + Pb (0.5 M)
2+
2+
1 + Pb (3 M)
2+
Absorbance
y = 0.16x - 0.06
2
R = 0.98
0.8
2+
1 + Pb (2 M)
A527 /A496
0.16
1 + Pb (1 M)
1 + Pb (4 M)
2+
1 + Pb (5 M)
0.12
0.6
0.4
0.2
0.0
0.08
0
1
2
2+
3
[Pb ] / M
4
5
0.04
0.00
400
450
500
550
600
650
700
Wavelength (nm)
Fig. S13 Absorption spectra of probe 1 (1 µM) upon addition of different concentrations of Pb2+ (0.5 – 5 µM) in
HEPES buffer (10 mM, pH 7.4, containing 1% acetonitrile) at 25 oC. Detection limit was determined to be 1
µM.
3. References
1. T.-I. Kim, J. Park, S. Park, Y. Choi and Y. Kim, Chem. Commun., 2011, 47, 12640.
2. J.-Y. Liu, H.-S. Yeung, W. Xu, X. Li and D. K. P. Ng, Org. Lett., 2008, 10 (23), 5421.
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