Biocompatible Ionic Liquid Based on Curcumin as Fluorescence Probe for Detecting Benzoyl Peroxide without the Interference of H2O2

Article abstract of DOI:10.1021/acs.analchem.9b00396

Accurate estimation of the level of benzoyl peroxide (BPO) is of considerable significance because of its threat to humanity and environment. Several research efforts have been devoted to the detection of BPO by fluorescent method with high sensitivity and selectivity. However, it remains challenging to eliminate the interference of H₂O₂ due to its similar properties to BPO. In this work, the first demonstration of fluorescent and colorimetric probe for specific detection of BPO without the disturbance of H₂O₂ was achieved by curcumin-based ionic liquid (CIL) that possesses simple fabrication, good biocompatibility, and low cost. The fluorescence quenches and emission peak blue-shifts once the probe selectively interacts with BPO, whereas the other possible interfering agents, including H₂O₂, do not have this phenomenon. The probe CIL exhibits prominent sensitivity for BPO sensing and enables the detection limit at levels as ultralow as 10 nM. The local detection of BPO in practical samples is realized by visualization using a portable device derived from CIL-based liquid atomizer.

Full text of DOI:10.1021/acs.analchem.9b00396

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Article
Biocompatible Ionic Liquid based on Curcumin as Fluorescence
Probe for Detecting Benzoyl Peroxide without the Interference of H2O2
Qiuhong Zhu, Wen-Li Yuan, Lei Zhang, Guohao Zhang, Ling He, and Guo-Hong Tao
Anal. Chem., Just Accepted Manuscript • Publication Date (Web): 26 Apr 2019
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Analytical Chemistry
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Biocompatible Ionic Liquid based on Curcumin as Fluorescence
Probe for Detecting Benzoyl Peroxide without the Interference of
H2O2
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Qiu-Hong Zhu, Wen-Li Yuan, Lei Zhang, Guo-Hao Zhang, Ling He* and Guo-Hong Tao*
College of Chemistry, Sichuan University, Chengdu 610064, China.
E-mail: lhe@scu.edu.cn, taogh@scu.edu.cn.
ABSTRACT: Accurate estimating the level of benzoyl peroxide (BPO) is of considerable significance because of its threat to
humanity and environment. Several research efforts have been devoted to the detection of BPO by fluorescent method with high
sensitivity and selectivity. However, it remains challenging to eliminate the interference of H2O2 due to its similar property to BPO.
In this work, the first demonstration of fluorescent and colorimetric probe for specific detection of BPO without the disturbance of
H2O2 is achieved by curcumin-based ionic liquid (CIL) that possesses simple fabrication, good biocompatibility and low cost. The
fluorescence quenches and emission peak blue-shifts once the probe selectively interacts with BPO, whereas the other possible
interfering agents including H2O2 do not have this phenomenon. The probe CIL exhibits prominent sensitivity for BPO sensing and
enables the detection limit at level as ultra-low as 10 nM. The local detection of BPO in practical samples is realized by visualized
and portable device derived from CIL-based liquid atomizer.
INTRODUCTION
either17,18. It means that these probes based on arylboronate
group were difficult to separate H2O2 from BPO during the
detection7. Silver nanorods with transverse and longitudinal
surface plasmon resonance have also been developed for the
detection of trace BPO19. However, inconvenient color
resolution, and poor selectivity limit their practical application.
Thus, searching for a novel fluorescent probe with high
sensitivity and selectivity to distinctly define BPO is still a
challenge.
Benzoyl peroxide (BPO) is an extensive ingredient used in
plastics, antimicrobial drugs, cosmetics, and a flour bleacher
in food industry1,2. However, as a strong oxidizer, the
widespread use of BPO is considered a potential threat to
humanity and environment. BPO plays critical roles in
mutagenicity of TA97 and TA1537 strains and it may be a
tumour promoter that can induce skin cancer3,4. In addition,
BPO is lipophilic, with a log Pow of 3.43 at 25 °C5. According
to data reported, the Koc value of BPO is 1,800 in soil5, which
means that BPO is low mobility and tends to accumulate if it
is released into the soil. BPO also shows high acute toxicity to
aquatic organisms, such as EC50 of algae, invertebrate and fish
is 0.07 mg/L, 2.91 mg/L and 0.24 mg/L, respectively6. BPO
should therefore be considered a contaminant to environment.
In European Union and China, BPO was prohibited as food
additives in wheat flour7,8. Therefore, accurate monitoring
BPO level is necessary to ensure human and environmental
safety.
As environmental friendly “green solvents and functional
materials”, ionic liquids (ILs) are considered to be essential
roles in various fields such as synthesis, electrochemistry,
extraction and analysis due to their highly tunable properties20-
29. Recently, more and more researches showed that ILs had
great potential in sensors30-33. Hice et al. provided a means for
rapidly capture and concentration of Salmonella by using
magnetic ILs. The concentrate sufficient cells could be
detected and a low detection limit was realized30. Che et al.
reported an anion-functionalized IL with high fluorescent
effect. They utilized the specific “chemical and physical” two-
step interaction between the anion and SO2 to design a
fluorescent sensor with good quantification and excellent
reversibility31. Be different from traditional sensors, IL-based
sensors possess a unique advantage of negligible vapor
pressure, which means the detection would not be influenced
by concentration change from solvent evaporation. The
adjustable characteristic of ILs makes it possible to meet
specific requirements by combining various cations and anions.
As a result, the sensors based on functional ILs can be
designed to exhibit exceptional selectivity for targeted
components34.
Current analytical methods used for the BPO detection
including HPLC9, spectrophotometry10, chemiluminescence11,
electrochemistry12,
colorimetry13,14
and
fluorescent
spectrometry7. Among them, fluorescent probes have attracted
tremendous attention due to its convenience, sensitivity, and
rapid response to BPO. Chen et al. first reported a fluorescent
probe for the BPO detection. The probe was designed to
incorporate an arylboronate group into resorufin matrix, which
could be employed to monitor BPO through the deprotection
of boronate7. In this context, several fluorescent probes have
been reported for the detection of BPO in living cells based on
this mechanism of deboronation15,16. However, H2O2, whose
property is similar to BPO, is an extremely sensitive mediation
with boronate and it causes the fluorescence response
Herein, we firstly designed a novel task specific ionic liquid
derived from biomass curcumin. The ionic liquid ([N3333][Cur],
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CIL) was prepared by an acid-base neutralization reaction
between curcumin and tetrapropylammonium hydroxide.
Benefited by the eminent optical activity and biocompatibility
of
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Scheme 1. Schematic Illustration for Specific Detection of BPO by the Colorimetric and Fluorescent Signals.
curcumin35, the CIL probe can simultaneously provide
colorimetric and fluorescent signals for BPO detection.
Importantly, the CIL probe exhibited highly sensitivity and
selectivity which had the identification to BPO from other
interferences including H2O2 (Scheme 1).
Rayleigh UV-1601 UV-vis spectrophotometer was employed
(a)
HO
OH
Curcumin
N
N
OH
H3CO
OCH3
Ethanol, 25 o
C
O
O
Probe CIL
EXPERIMENTAL SECTION
(b)
CH3
O
O
C
H
Materials.
Curcumin,
benzoyl
peroxide,
O
O
C
O O H
C
O O
H
tetrapropylammonium hydroxide (TPAH) (25%) and cumene
hydroperoxide (CHP) (60%) were purchased from J&K
Scientific Ltd. (Beijing, China). Glucose, vitamin C, glycine,
arginine, serine, K2S2O8, K2Cr2O7, NaNO3, MgSO4, ZnCl2,
KCl, NaCl, H2O2, ethanol were sourced from Sinopharm
Chemical Reagent Co. Ltd. (Shanghai, China). Benzoyl
peroxide gel was purchased from Mingxin Pharmaceutical Co.,
Ltd. (Shanghai, China). Wheat flour was purchased from local
supermarket. All chemicals and reagents of analytical grade
were obtained commercially and used without further
purification. Ultrapure water of 18 MΩ cm was used
throughout the experiments.
CH3
H2O2
BPO
CHP
Scheme 2. (a) Design and synthesis of CIL probe. (b)
Chemical structures of BPO, H2O2 and CHP used in the tests.
to measure UV-vis absorption spectra. Steady state
fluorescence spectra were recorded by a Shimadzu RF-
5301PC fluorescence spectrophotometer with a xenon lamp as
the excitation source. The slits widths for excitation and
emission were set to 3.0 nm, 5.0 nm, respectively. The mass
spectra of the samples were measured on an LCMS-IT-TOF
using methanol as solvent. High-performance liquid
chromatography (HPLC) analyses were conducted on a
Shimadzu HPLC system, equipped with LC-20AD solvent
Instruments and Characterization. Fourier transform
infrared spectra (FT-IR) were recorded on a Bruker ALPHA
infrared spectrometer in the range of 400−4000 cm−1 at the
resolution of 2 cm−1 and 32 scans per time. NMR experiments
were performed with a Bruker 400 MHz nuclear magnetic
resonance spectrometer operating at 400 (1H) and 100 (13C)
MHz, respectively, with DMSO-d6 as the locking solvent. The
elemental analysis (H, C, N) of the sample was determined
using an Elementar Vario MICRO CUBE elemental analyzer.
delivery unit, SIL-20A autosampler and
photodiode array detector. The methanol/water (80:20, v/v)
was used as mobile phases.
a SPD-M20A
Synthesis of Probe CIL. The proposed fluorescent probe
CIL could be easily synthesized according to a literature
method by the acid-base neutralization36 between curcumin
and tetrapropylammonium hydroxide without any poisonous
by-product (Scheme 2). In brief, the curcumin precursor (0.05
g, 0.14 mmol) was dissolved in 30 mL ethanol. Then the
aqueous solution of tetrapropylammonium hydroxide (ratio
1:1) was added to the system. The mixture was stirred for 24 h
at room temperature, and then desirable CIL-based probe was
1
obtained after drying using a high vacuum pump. H NMR
(400 MHz, DMSO-d6): δ 7.35 (d, J=11.6 Hz, 2H), 7.02 (s, 2H),
6.94 (d, J=8.2 Hz, 2H), 6.51−6.31 (d, J=59.2 Hz, 4H), 5.74 (s,
1H), 3.73 (s, 6H), 3.15–3.05 (m, 8H), 1.65–1.53 (m, 8H), 0.88
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(t, J=7.2 Hz, 13H) ppm. 13C NMR (100 MHz, DMSO-d6): δ
183.13, 150.34, 148.22, 140.77, 125.84, 123.38, 120.71,
115.86, 111.27, 100.90, 59.25, 55.68, 14.81, 10.56 ppm.
Elemental analysis: Calcd. for C33H47NO6 (553.75): C, 71.61;
H, 8.49; N, 2.53; Found: C, 71.56; H, 8.38; N, 2.20.
ments were freshly prepared in ethanol. In test system, 0.25
mL stock solution of CIL probe (0.05 mM) and various
volume standard solution of BPO were mixed. The final
volume was adjusted to 5 mL with ethanol. The fluorescence
and UV-vis spectra of the mixture solution were collected
after sonication for 10 min and incubation for 60 min at room
temperature.
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Detection of BPO in solution state. The standard solutions
of CIL probe (1.0 mM) and BPO (5 mM) were prepared in
ethanol. All solutions of fluorescence and UV-vis measure-
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Fig 1. (a) UV-vis absorption and (b) fluorescence emission spectra of CIL probe, BPO and CIL probe in the presence of 300.0 μM
BPO in ethanol, λex = 365 nm; the inset shows photographs of changes of color and fluorescence under day light and UV light (365
nm). (c) UV-vis absorption and (d) fluorescence emission spectra of the solutions of CIL probe with various concentrations of BPO,
including 0, 0.1, 0.5, 1.0, 5.0, 10.0, 20.0, 30.0, 50.0, 100.0 μM in UV-vis spectra; 0, 0.1, 0.5, 1.0, 5.0, 10.0, 20.0, 30.0, 50.0, 100.0,
200.0, 300.0, 500.0 μM and 1.0 mM in fluorescence spectra.
Detection of BPO in real samples. Wheat flour and benzo-
yl peroxide gel were selected as the real samples. First, 0.10 g
wheat flour and an appropriate volume of BPO standard
solution (0, 5, 10, 20 μM) were added into 1 mL CIL probe
stock solution, and then a final volume was adjusted to 5 mL
with ethanol. For benzoyl peroxide gel, 0.10 g gel and 0.20
mM CIL probe were mixed into ethanol. All mixture solutions
were incubated at room temperature for 60 min and
centrifuged at 5000 rpm for 10 min. The supernatants were
tested by UV-vis absorption and fluorescence spectra with λex
= 365 nm.
spectrum (Fig S1). In the FT-IR spectra of curcumin and probe
CIL (Fig S2), the new peaks observed at 2828−2970 cm−1
were assigned as the symmetric and asymmetric stretching
vibration of C−H groups of tetrapropylammonium. The
remarkable blue-shifted from at 1697 cm−1 to at 1575 cm−1
was ascribed to the characteristic peak of C=O group of
curcumin substrate. The stretching vibration of C=C group
was observed at 1626 cm−1 and the aromatic C=C stretching
vibration was found at 1474 cm−1. The product was further
confirmed by elemental analysis. All these results suggested
the probe CIL was successfully synthesized.
RESULTS AND DISCUSSION
Detection of BPO by Colorimetric Signal and Fluores-
cent Signal. To verify the effective interaction between the
probe CIL and BPO system, we tested the response of probe
CIL in the absence and presence of BPO by UV-vis absorption
and fluorescence spectra. The detecting behavior of probe CIL
toward BPO were presented in Figure 1. In UV-vis absorption
spectra (Fig 1a), the probe CIL displayed a strong absorption
at 426 nm due to π−π* transition of the extended conjugated
system37. Interestingly, after addition of BPO, the original
absorption peak of probe CIL at 426 nm almost disappeared
and the peak intensity at 270 nm increased significantly. It
means that a redox reaction may occur when the addition of
BPO. Meanwhile, a significant color change of the system
from blood red to nearly colorless can be observed by naked
Characterization of CIL Probe. The structure of the
obtained probe CIL was characterized by H and 13C NMR,
1
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FT-IR and elemental analysis. Compared with the H NMR
spectrum of curcumin (Fig S1), some new signals at 0.86−3.15
ppm appeared, which were attributed to the proton of the ─
CH3 and ─CH2 group of TPAH parent material. Furthermore,
the chemical shift from at 9.67 ppm to at 4.83 ppm was
allocated to the proton of phenol groups of curcumin, and
shape of the peak changed from sharp to broad visibly. The
electron pairs of negative ion are speculated to be delocalized
after the reaction and shared among the whole conjugate
system with the affection of proton activity belonged to the
phenol. The slight shifts can also be observed in 13C NMR
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eyes, as demonstration in the inset of Fig 1a. The result
indicates that the prepared CIL can be used as a colorimetric
probe for BPO detection.
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The response of CIL probe to BPO also tested by
fluorescent strategy. As shown in Fig 1b, in the absence of
BPO, the probe CIL shows a maximal fluorescence emission
at 544 nm with the excitation wavelength at 365 nm. While
once probe CIL meets BPO, vary weak fluorescence emission
intensity was found at about 470 nm. It means that the addition
of BPO induces the behavior of a specific fluorescence
quenching in probe CIL, accompanied by a distinct visual
change from bright-yellow to colorless under the UV light
illumination (365 nm) in the dark (in the inset of Fig 1b).
Interestingly, the emission peak undergoes blue-shift from 544
nm to 470 nm compared to the original CIL probe system.
This specific change could be attributed to efficient redox
reaction between CIL and BPO, which would induce
deterioration of CIL probe and destruction of conjugated
system. These fluorescent evidences were consistent with the
observation from UV-vis absorption spectra. The results
demonstrated that BPO can be simple identified by CIL-based
fluorescence probe.
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Analytical Performance of Probe CIL for BPO Detection.
To evaluate the activity of the CIL-based sensor for BPO
detection, we conducted the gradient experiments of CIL
probe with various concentrations of BPO under the optimal
conditions (the optimal conditions are shown in Supporting In-
formation). As illustrated in Fig 1c, with an increase in the
concentrations of BPO, the peaks of reaction solutions exhibit-
ed a downward trend at 426 nm, and instead rise at 270 nm in
UV-vis absorption spectra. Meanwhile, a new absorption peak
emerged at 367 nm upon the addition of BPO. The changes of
fluorescent signals for BPO response were also studied (Fig
1d). It can be seen that the fluorescence intensity of the
systems gradually decreases and the fluorescence response
regularly blue-shifts with the concentrations of inserted BPO
increases. Photographs of probe CIL with various
concentrations of BPO under day light and UV light (365 nm)
were shown in Fig 2. The changes are visualized and the
presence of BPO can
Fig 2. Photographs of various BPO concentrations in presence
of 0.2 mM CIL under day light and UV light (365 nm), BPO
concentrations including: 0, 1.0, 5.0, 10.0, 20.0, 50.0, 100.0
and 300.0 μM.
be direct recognized by naked eyes. These observations
proved that the as-prepared CIL possesses an excellent
sensitivity to BPO. The relationship between changes in
fluorescence intensity (ΔF = F0 − F) and various BPO
concentrations was depicted in Fig 3a. The linear correlation
equation was shown as ΔF = 177.7CBPO + 2.063 (R2 = 0.995).
The detection limit toward BPO by the fluorescent strategy
used is 10 nM (n = 5), which was lower than previous reported
probes for BPO. The detection limits of published literature in
this field were summarized in Table S1. The time-dependence
kinetic measurement was also established by UV-vis
spectroscopy (Fig 3b) and it further demonstrates the great
sensitivity of CIL probe in BPO monitoring.
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Fig 3. (a) Change trend of fluorescence intensity (ΔF) in the
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presence of various BPO concentrations; the inset shows the
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linear relationship between fluorescence intensity (ΔF) and
BPO
concentrations.
(b)
Time-dependence
kinetic
measurement of UV-vis response of CIL probe toward
different BPO concentrations from 0 to 100.0 μM.
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Specificity of CIL toward BPO. Specificity of probe is
considered to be of great significance for its practical applica-
tion. To confirm the specificity and selectivity of method
proposed toward BPO, we examined the effects of various po-
tential disturbances in parallel by control experiments. The
results demonstrated that BPO could be identified by CIL spe-
cifically. As shown in Fig 4, under same conditions, only BPO
can produce a dramatic fluorescence quenching and blue-shift
behavior, whereas the other interference tested including
common oxidants hardly changed in fluorescence spectra.
More importantly, compared to BPO, H2O2 do not show these
unique behaviors. This shows that the used probe can
eliminate the interference of H2O2 in BPO detection process.
To verify this, fluorescence spectra of different H2O2
concentrations (10 μM to 300 μM) were collected under
optimum conditions. As shown in Fig S5, fluorescence
quenching and blue shift were not observed with the increase
of H2O2 concentration. To the best of our knowledge, this is
the first time to eliminate the interference of H2O2 in
fluorescent method for BPO sensing. Cumyl hydroperoxide
(CHP), a substance similar to H2O2, also has no interference
with the fluorescence detection of BPO (the structure was
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shown
in
Scheme
2).
The
Fig 4. (a) Fluorescence emission spectra (λex = 365 nm) of CIL probe and its mixture with various coexisting substances including
50.0 μM of BPO, CHP, K2S2O8, K2Cr2O7, vitamin C, glucose, glycine, arginine, serine, NaNO3, MgSO4, ZnCl2, KCl, NaCl, and
10.0 μM of H2O2. (b) Fluorescence intensity of CIL probe in the presence of 10.0 μM H2O2, 50.0 μM BPO and other coexisting
substances.
FT-IR analysis of products formed further proved the specific
interaction between CIL and BPO (Fig S6, S7). The results
suggested that the CIL-based sensor possesses a strong
specificity and selectivity.
that the chemical structure of BPO was broken and a new
substance, benzoic acid, may be formed. To prove this, the
FT-IR spectra of benzoic acid and the mixture of benzoic acid
and CIL were recorded. As displayed in Fig 5, C=O group of
benzoic acid was observed at 1678 cm−1 in pure sample and at
1690 cm−1 in CIL atmosphere. This is consistent with the new
peak of the product formed between CIL and BPO. Moreover,
the characteristic C−H vibrations of benzoic acid at 2544 cm−1
to 3069 cm−1 can be all found in the FT-IR spectrum of the
product. The benzoic acid also was observed in HPLC-MS
Mechanism Studies. To explore the possible mechanism of
CIL probe for selective response with BPO, the reaction
products formed were conducted to FT-IR, 1H NMR and
HPLC-MS analyses. In the FT-IR spectra of products of CIL
with various BPO ratios (Fig S8), a new signal peak appeared
at 1690 cm−1 with the increase of BPO. Compared with the
original BPO, the peaks assigned to the C=O bond of BPO at
1781 cm−1 and 1756 cm−1 disappeared (Fig S6). This indicated
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surface of wheat flour samples. The change of color and
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fluorescence can be easily observed with naked eyes. It is
worthy to mention that the UV analyzer can be replaced by
miniature and carriable ultraviolet flashlight (365 nm)
purchased commercially, and the atomizer can still effectively
display fluorescent signal. As an alternative device, the
atomizer designed can meet the requirements of rapid and
local monitoring of BPO without any specialized equipment
and extra pretreat-ment. The initial results have proved that
CIL-based liquid atomizer can be employed as a portable
device for the detec-tion of BPO in real samples.
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Fig 5. FT-IR spectra of benzoic acid, the mixture of benzoic
acid and CIL, and the product formed after the reaction of CIL
probe with BPO.
spectrum of the product at 121.0312 ([benzoic acid - H]—: m/z
calcd. 121.0325, found 121.0312) (Fig S9). In addition,
benzoic acid was further verified as a product by NMR
analysis. As shown in Fig S10, the proton peaks of benzoic
acid were found in 1H NMR spectrum of product at 7.35, 7.41,
and 7.90 ppm. The proton of carboxyl group of benzoic acid
was not observed because of the alkaline environment of CIL
system. These data confirmed our conjecture.
Fig 6. Photographs of wheat flour in the absence and presence
of BPO after spraying and incubating for an hour using the
liquid atomizer device; (a) and (c) showed the wheat flour
without BPO in day light and UV light, respectively; (b) and
(d) showed the wheat flour containing 500.0 μM BPO in day
light and UV light, respectively.
Assays of Real Wheat Flour and Drug Samples. Many
countries have resolutely banned BPO as a food additive in
wheat flour, while there are still some businesses having viola-
tions to their profitableness. Therefore, the quantitative detec-
tion of BPO in real samples is of prime important for ensuring
the safety of humanity and environment. To confirm the prac-
tical applicability of CIL probe for BPO, we determined the
recovered BPO concentrations in real samples matrix. The
results are encouraging in wheat flour and benzoyl peroxide
gel (a drug containing 50 mg BPO per gram for acne). In
wheat flour samples, 10.00 μM, 20.00 μM BPO were added,
and 9.94 μM, 20.45 μM were found by testing, respectively.
Furthermore, a lower content of BPO (5.00 μM) was tested
through the same strategy and similar result could be obtained
(5.06 μM was found). The great recoveries of the tests close to
100.0% were obtained, and the relative error no more than 3%
(Fig S11, S12 and Table S2). For benzoyl peroxide gel sample,
an obvious color change was observed upon the addition of gel
into the probe solution (Fig S13, S14 and Table S2). The BPO
was found from our test to be 5.03 mg in the 0.10 g gel, which
was consistent with available data in the instructions of
benzoyl peroxide gel commercially (Table S2). The method
adopted was proved by HPLC analysis (Table S2). All results
indicate that CIL probe is feasible for quantitative analysis of
BPO in real samples.
CONCLUSIONS
In summary, a novel IL probe derived from biomass
curcumim has been firstly designed and prepared. With the
obvious color and prominent optical properties, the CIL can
simultaneously provide colorimetric and fluorescent signals,
and enable the detection limit of BPO at ultra-low level of 10
nM. The BPO triggered a unique behavior of fluorescence
quench and emission peak blue-shift, whereas other
interferences including H2O2 do not have this phenomenon.
The excellent specificity and selectivity allowed the
successfully detection of BPO in real samples such as wheat
flour and antibacterial agent. In addition, a promising spot test
device based on atomizer was fabricated, which can satisfy the
demands as portable detectors. The BPO in samples could be
identified conveniently and reliably by the CIL atomizer. In
our work, we first achieved specific detection of BPO without
the disturbance of H2O2 by CIL probe proposed.
ASSOCIATED CONTENT
Supporting Information
Portable Detector Applies. After demonstrating that the
CIL probe has an excellent performance for BPO sensing, we
fabricated a portable device to realize a convenient and real-
time detection. The CIL solution of appropriate concentration
(1.0 mM) was poured into a pushing liquid atomizer, and its
ability to identify BPO in real samples was measured. The
results of the tests were showed in Fig 6. The CIL liquid
sensor designed could be well atomized and distributed on the
The NMR and FT-IR spectral analyses (Fig S1, S2), optimization
of operation conditions (Fig S3, S4), the fluorescence spectra of
various H2O2 concentrations (Fig S5), the FT-IR analysis of
products (Fig S6–S8), HPLC-MS and 1H NMR spectrum of
product (Fig S9, S10), BPO detection in real samples (Fig S11–
S14, and table S2). Summary of published literature (table S1).
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Analytical Chemistry
peroxidases naturally immobilized on coconut fibers. Biosens.
Bioelectron. 2010, 25, 1143-1148.
The Supporting Information is available free of charge on the
ACS Publications website.
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AUTHOR INFORMATION
Corresponding Author
14. Lin, T. R.; Zhang, M. Q.; Xu, F. H.; Wang, X. Y.; Xu, Z. F.;
Guo, L. Q., Colorimetric detection of benzoyl peroxide based on the
etching of silver nanoshells of Au@Ag nanorods. Sens. Actuators B
2018, 261, 379-384.
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*E-mail: lhe@scu.edu.cn. taogh@scu.edu.cn.
Fax & Tel: (+86)-28-85470368
Author Contributions
15. Wang, L. Q.; Zang, Q. G.; Chen, W. S.; Hao, Y. Q.; Liu, Y. N.;
The manuscript was written through Q.-H.Z., G.-H.Z., G.-H.T.
and L.Z.. L.H., G.-H.T. and W.-L.Y. designed the project. Q.-H.Z.,
and W.-L.Y. performed the experiments and analyzed the data.
All authors have given approval to the final version of the
manuscript.
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Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
The finance support of National Natural Science Foundation of
China (No. 21876120), and China Scholarship Council are
gratefully acknowledged. We gratefully acknowledge the platform
of specialized laboratory, College of Chemistry, Sichuan
University and the Analytical and Testing Center of Sichuan
University for instrumental measurements.
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