Preparation of ionic liquid-modified magnetic nanoparticles based on thiol-ene click chemistry for the analysis of polycyclic aromatic hydrocarbons in water and smoked meat samples

Article abstract of DOI:10.1002/jccs.201800377

In the present study, ionic liquid (IL)-modified Fe₃O₄ magnetic nanoparticles (Fe₃O₄) were synthesized by the thiol-ene click reaction for magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in water and smoked meat samples. An IL 1-vinyl-3-butylimidazolium bromide was firstly synthesized, and then immobilized on the surface of thiol group-functionalized Fe₃O₄ via a thiol-ene click reaction. The as-synthesized Fe₃O₄@ILs were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy. Various parameters (including the amount of adsorbent, extraction time, sample volume, and desorption conditions) affecting MSPE were optimized. Under the optimum conditions, the limits of detection of four PAHs in the range of 0.6–7.2 ng/L were obtained using high-performance liquid chromatography–ultraviolet detection. The accuracy of the method was assessed by recovery measurements on spiked real samples and good recovery of 80–108% with relative standard deviations lower than 8.16% was achieved. The enrichment factors ranging from 699 to 858 were obtained for the analytes. This result indicated that the proposed method had great potential for sample preparation.

Full text of DOI:10.1002/jccs.201800377

Received: 6 October 2018
Revised: 5 December 2018
Accepted: 13 December 2018
DOI: 10.1002/jccs.201800377
A R T I C L E
Preparation of ionic liquid-modified magnetic nanoparticles
based on thiol-ene click chemistry for the analysis of polycyclic
aromatic hydrocarbons in water and smoked meat samples
Junyu Lu | Sufen Lu | Dongmei Yao | Xiuxiang Huang | Hongfang Lai | Xiuju Yin
College of Chemistry and Biology Engineering,
In the present study, ionic liquid (IL)-modified Fe3O4 magnetic nanoparticles
Hechi University, Yizhou, China
(Fe3O4) were synthesized by the thiol-ene click reaction for magnetic solid-phase
Correspondence
Junyu Lu, College of Chemistry and Biology
extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in water and
smoked meat samples. An IL 1-vinyl-3-butylimidazolium bromide was firstly syn-
thesized, and then immobilized on the surface of thiol group-functionalized Fe3O4
Engineering, Hechi University, Yizhou 546300,
China.Email: gxlujunyu@163.com
Xiuju Yin, College of Chemistry and Biology
Engineering, Hechi University, Yizhou 546300,
China.
via a thiol-ene click reaction. The as-synthesized Fe3O4@ILs were characterized
using Fourier transform infrared spectroscopy, X-ray diffraction, and transmission
electron microscopy. Various parameters (including the amount of adsorbent,
extraction time, sample volume, and desorption conditions) affecting MSPE were
optimized. Under the optimum conditions, the limits of detection of four PAHs in
the range of 0.6–7.2 ng/L were obtained using high-performance liquid
chromatography–ultraviolet detection. The accuracy of the method was assessed
by recovery measurements on spiked real samples and good recovery of 80–108%
with relative standard deviations lower than 8.16% was achieved. The enrichment
factors ranging from 699 to 858 were obtained for the analytes. This result indi-
cated that the proposed method had great potential for sample preparation.
Email: gxyxj505@163.com
Funding information
higher-level talents scientific research projects
funded start-up funds of Hechi University, Grant/
Award Number: XJ2018GKQ012; Natural Science
Foundation of Guangxi Province, Grant/Award
Number: 2014GXNSFBA118045, 2015GXNSF
AA139030, 2017GXNSFAA198118, 2018
GXNSFAA138140; project of undergraduate
teaching reform of higher education in Guangxi,
Grant/Award Number: 2018JGA254
KEYWORDS
ionic liquids, magnetic solid-phase extraction, polycyclic aromatic hydrocarbons,
smoked meat, thiol-ene click chemistry, water samples
Therefore, it was of great importance to develop sensitive,
reliable, and easily operating analytical methods for the deter-
1
| INTRODUCTION
Polycyclic aromatic hydrocarbons (PAHs) are a class of per-
sistent pollutants widely distributed in the natural environment
and existed in soil, sediments, water, atmosphere, and ani-
mals.[1,2] These organic pollutants are commonly generated
by human activities, mainly the incomplete burning of organic
materials such as coal, petrol, gas, tobacco, and garbage.[3] In
the last few decades, scientists have made great efforts to
monitor and determine PAHs due to their high toxicity, carci-
nogenicity, teratogenicity, and mutagenicity.[4,5] PAHs have
been considered hazardous to human beings by migrating
through the food chain and accumulating in living organisms.
mination of PAHs in environmental samples. Several routine
methods for analyzing PAHs are chromatographic techniques,
including high-performance liquid chromatography coupled
with UV,[6] diode array detection,[7,8] fluorescence
detection,[9,10] and gas chromatography coupled with mass
spectrometry (GC–MS).[11,12] However, the direct determina-
tion of PAHs in environmental samples is a difficult task due
to the complex matrices and a very low concentration level.
Consequently, prior to chromatographic analysis, a sample
preparation step, which aims to concentrate the target analytes
and eliminate matrix interference, is, therefore, indispensable.
© 2019 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
J Chin Chem Soc. 2019;1–8.
http://www.jccs.wiley-vch.de
1

2
LU ET AL.
Ionic liquids (ILs) are a class of molten salts containing
potential to modify Fe3O4 nanoparticles (NPs) with mild
reaction conditions at room temperature. These important
research studies inspire us to explore novel functionalized
materials to be used as MSPE adsorbents for enrichment of
organic pollutants from environmental water samples. How-
ever, preparation of IL-modified Fe3O4 through thiol-ene
reaction for enriching PAHs has not been reported.
In this study, a novel thiol-ene click chemistry strategy
was proposed for the preparation of IL-modified Fe3O4
(Fe3O4@ILs) for MSPE, which are used as adsorbents for
the enrichment of PAHs. Fe3O4@ILs were facilely synthe-
sized based on the thiol-ene click reaction between 1-vinyl-
3-butylimidazolium bromide and thiol-functionalized Fe3O4.
Four PAHs, including fluorene (Flu), anthracene (Ant), pyr-
ene (Pyr), and fluoranthene (Fla), were selected as model
analytes to evaluate the extraction performance of the pre-
pared nanoadsorbent. The significant experimental factors
affecting the extraction recoveries were examined. The
results of analyzing four PAHs in water and smoked meat
samples were proven to be applicable.
organic cation and inorganic or organic anions with unique
and fascinating properties, including low volatility, good
thermal stability, miscibility, and tunable viscosity.[13,14]
These fascinating properties have made significant contribu-
tions in the field of analytical chemistry.[15] Especially, ILs
have been widely used for sample pretreatment, such as
liquid–liquid
extraction,[16,17]
mixed hemimicelles
liquid-phase
micro-
extraction,[18,19]
solid-phase
extraction,[20,21] and solid-phase micro-extraction.[22,23] In
recent years, IL-modified Fe3O4 as an adsorbent for mixed
hemimicelle solid-phase extraction has been studied by the
research group of Yao.[24] Cheng et al.[25] utilized IL-coated
Fe3O4 as an adsorbent for the preconcentration of two chlor-
ophenols in water samples. Liu et al.[26] prepared
Fe3O4@ILs@methyl orange nanoadsorbent through self-
assembly for the extraction of target analytes. Cao et al.[27]
have synthesized IL-coated Fe3O4@ grapheme nanocom-
posites and used to extract nitrobenzene compounds in
environmental water samples. The application of IL-
functionalized Fe3O4 has become an important separation
technology in sample preparation. However, preparation of
IL-modified Fe3O4 in solid-phase extraction is still at an
early stage.
2
| EXPERIMENTAL
2.1 | Chemicals and materials
Nowadays, magnetic solid-phase extraction (MSPE) has
attracted increasing attention attributing to its great potential
application in different areas.[28] A distinct advantage of this
technology is that magnetic materials can be readily isolated
from sample solutions by the application of an external mag-
netic field, which makes the method environmentally
friendly and economical.[29,30] Consequently, there have
been several methods developed to introduce desired func-
tionalities onto the surfaces of Fe3O4. Yao's group utilized
the triphenylamine-functionalized magnetic microspheres as
sorbents for the enrichment of PAHs in water samples.[31] Li
et al.[32] described surface-exchangeable core@shell
Fe3O4@Au nanoparticles for MSPE. Zhu et al.[33] prepared
a magnetic graphene oxide composite and applied for the
determination of PAH metabolites in human urine. Wang
et al.[34] developed a method for the extraction of five PAHs
from water samples using magnetic microsphere-confined
(3-Mercaptopropyl) trimethoxysilane (MPTMS) (98%), tet-
raethoxysilane (TEOS) (98%), vinylimidazole (98%),
1-bromobutane (98%), dimethyl sulphoxide (DMSO) and
azobisisobutyronitrile (AIBN) were purchased from Alfa
Aesar (Ward Hill, MA, USA). Potassium hexacyanoferrate
(II) trihydrate, zinc sulfate heptahydrate, fluorene, anthra-
cene, pyrene, and fluoranthene were obtained from Sigma-
Aldrich (St. Louis, MO, USA). All the iron (III) chloride
hexahydrate, sodium acetate trihydrate, ethylene glycol,
absolute alcohol, isopropanol, glacial acetic acid, triethyla-
mine, ammonium hydroxide, toluene, hydrochloric acid,
potassium hydroxide, and sodium hydroxide, etc., were of
analytical grade. High-performance liquid chromatography
(HPLC)-grade methanol and acetonitrile were purchased
from Shanghai Chemical Reagents Corporation (Shanghai,
China). The ultrapure water used for the preparation of solu-
tions was produced by a Yue Chun water system (Chengdu,
China). All samples were filtered (MFS-25, 0.22 μm, Shang-
hai, China) before being injected into the HPLC system.
grapheme as
a
sorbent. Meng et al.[7] synthesized
polydopamine-coated Fe3O4 for enrichment of PAHs from
environmental water samples. Recently, great interest was
aroused in the use of the thiol-ene reaction in materials sci-
ence, synthesis, and modification.[35] To date, the thiol-ene
reaction has been widely used in the materials arena, great
efforts have been made to fabricate surface functional Fe3O4
via thiol-ene click reaction. Zhang et al.[36] prepared boronic
acid-functionalized Fe3O4 via a thiol-ene click reaction, and
for preconcentration of proteins in complex biosamples.
Liang et al.[37] reported the introduction of ferrocene onto
the surface of Fe3O4 via a UV-induced thiol-ene reaction.
These studies indicate that thiol-ene reaction has the
2.2 | Apparatus
The morphology and sizes of the Fe3O4@ILs were charac-
terized by transmission electron microscopy (TEM, FEI Tec-
nai G20). The characterization of the crystalline phase was
performed on a Rigaku D/max 2500/PC (Japan) X-ray
diffraction (XRD) with a Cu Kα source. Fourier transform
infrared (FT-IR) spectroscopy was conducted on a Thermo
Nicolet 6700 FT-IR spectrometer over the range of

LU ET AL.
3
500–4,000 cm−1. The electrospray ionization mass spectra
stirred for 6 hr at 50ꢀC. The resultant product was collected
by using a magnetic field and washed with deionized water,
ethanol in turn. The obtained Fe3O4@ILs were dried in a
vacuum for use. The preparation procedure is illustrated in
Figure 1a.
(ESI-MS) were recorded using the Bruerhct (Bruker, Ger-
1
many) operated in the positive ion mode. H-NMR spectra
were recorded using a Bruker Avance AV 500 spectrometer.
A KQ2200DE ultrasonic bath with temperature control
(Kunshan Shumei Ultrasonic Instrument, Suzhou, China)
was used to disperse the nanoparticles in the solution. A
microwave extraction lab station (MDS-10 Sineo, Shanghai,
China) was employed to extract target analytes from solid
matrices. The reported pH of solution was carefully mea-
sured using a PHS-3B pH-meter (Shanghai, China). An Nd–
Fe–B magnet (8.0 × 6.0 × 1.6 mm) was used for magnetic
separation.
2.5 | Sample collection
Three types of water samples were collected randomly,
including river water collected from Longjiang River
(Yi zhou, Guangxi), tap water collected from the local sup-
ply system (Yizhou, Guangxi), wastewater obtained from
our laboratory. All water samples were filtered through a
0.22 μm membrane syringe filter to remove the suspended
solids, and stored at 4ꢀC before use.
The smoked meat sample was randomly purchased from
a local market and stored at −20ꢀC in the dark until further
use. The smoked meat sample was minced in a meat grinder,
and the extraction procedures were performed according to
Kamankesh et al.[40]
2.3 | Synthesis of IL
The IL (1-vinyl-3-butylimidazolium bromide) was synthe-
sized according to the procedures as described in our previ-
ous work.[38] 1-Bromobutane (4.11 g, 0.03 mol) and
1-vinylimidazole (2.82 g, 0.03 mol) were added to a dry
three-necked round-bottomed flask, then ethanol (50 mL)
was added into the bottle as a solvent. The mixture was
refluxed for 48 hr under nitrogen with stirring at 60ꢀC. The
obtained red-brown viscous product of the IL was washed
several times with ethyl acetate and dried under vacuum.
Yield: 96%. The obtained product was characterized by FT-
IR (Figure S1), ESI-MS (Figure S2) and 1H-NMR
(Figure S3), and spectral data for IL were as follows: FT-IR
(KBr, ν, cm-1), 3,428.4, 3,060.2, 2,962.2, 2,868.3, 1,648.2,
1,569.5, 1,456.9, 1,374.9, 1,172.5, 1,116.3, 1,022.3, 957.3,
2.6 | MSPE procedure
The MSPE procedure is illustrated in Figure 1b. First,
Fe3O4@ILs were cleaned and activated with 5 mL acetoni-
trile and 5 mL water in order. Afterward, Fe3O4@ILs were
incubated in a sample solution spiked with PAHs. To
completely capture the target analytes, the mixture was soni-
cated for 3 min to suspend Fe3O4@ILs, and allowed to stand
for 5 min. After that, the Fe3O4@ILs were collected using a
magnetic field. After discarding the supernatant solution,
3 × 2 mL acetonitrile was added to the Fe3O4@ILs and son-
icated for 1 min to release the PAHs. The eluate was col-
lected and dried with a stream of nitrogen at 50ꢀC. The
1
and 751.2. ESI-MS, m/z at 152.12 [M-Br]+ ions. H-NMR
(500 MHz, DMSO), 9.64 (1H, s), 8.26 (1H, d), 7.98 (1H, d),
7.31 (1H, dd), 5.99 (1H, dd), 5.42 (1H, dd), 4.22 (2H, t),
1.81 (2H, m), 1.28 (2H, m), and 0.90 (3H, t).
2.4 | Preparation of Fe3O4@ILs
Fe3O4 was prepared via a common solvothermal reaction.[39]
After the reaction, the obtained Fe3O4 was dispersed into
150 mL of ethanol and sonicated for 10 min, then 10 mL of
26.5% aqueous ammonia and 4 mL TEOS were added suc-
cessively. After that, the mixture was stirred for 24 hr. The
resultant product was separated from the reaction medium
by applying a magnetic field, followed by rinsing with etha-
nol four times and drying in a vacuum.
An amount of 0.6 g of the SiO2-coated Fe3O4 was dis-
persed into 50 mL anhydrous toluene, then 4.0 mL MPTMS
and 2 mL triethylamine were added. The mixture was stirred
for 24 hr under reflux at 90ꢀC. After cooling to room tem-
perature, the resultant product was collected by applying a
magnetic field, followed by rinsing with toluene, ethanol-
water mixture (1:1, vol/vol), and ethanol in sequence. After
drying under vacuum at 50ꢀC for 12 hr, the as-prepared
thiol-terminated Fe3O4 was dispersed in 50 mL ethanol, then
0.5 g ILs and 25 mg AIBN were added and the mixture was
FIGURE 1 Schematic illustration of the synthesized Fe3O4@ILs (a).
Procedure for MSPE of water sample using Fe3O4@ILs (b)

4
LU ET AL.
residue was redissolved in 100 μL acetonitrile and filtered
through a 0.22 μm membrane syringe filter. Finally, 15 μL
of this solution was injected for HPLC analysis.
2.7 | HPLC analysis
HPLC was performed using an Agilent Technologies (Santa
Clara, CA, USA) 1,200 liquid chromatograph equipped with
a UV detector. An Agilent Zorbax SB-C18 column
(100 × 4.6 mm) and a particle size of 3.5 μm were used for
all analyses. The mobile phase consisted of methanol and
0.1% (vol/vol) aqueous acetic acid in a ratio of 85:15 (vol/-
vol), the flow rate was set at 0.6 mL/min, the column tem-
perature was 30ꢀC, the detection wavelength was set at
254 nm.
FIGURE 3 FT-IR spectra (a) and XRD patterns (b) of Fe3O4 (A),
Fe3O4@ILs (B)
(311), (400), (422), (511), and (440) planes of the Fe3O4 lat-
tice, respectively. This result indicated that the crystalline
structure of Fe3O4 was not changed during the coating pro-
cess. In addition, the peak at 2θ = 25.1ꢀ can be attributed to
the presence of amorphous silica.[41] The decline of the mag-
netic strength is likely attributed to the coating of nonmag-
netic shells on magnetic particles. This phenomenon proves
the successful preparation of Fe3O4@ILs.
3
| RESULTS AND DISCUSSION
3.1 | Characterization of Fe3O4@ILs
The morphology and size of the prepared Fe3O4@ILs were
characterized by TEM. As can be seen from Figure 2, the
Fe3O4 and Fe3O4@ILs were of spherical shape, and have
relatively good monodispersity. After Fe3O4 was coated with
silica and further modified with ILs, a dark Fe3O4 core was
coated with a gray shell (Figure 2b). This result proves that
Fe3O4-supported silica-IL nanoparticles were synthesized.
The synthesized Fe3O4@ILs were further characterized
using FT-IR. Figure 3a describe the FT-IR spectra of differ-
ent materials. As can be seen, the peaks at about 580 and
3,200 cm−1 appearing in all curves correspond to the Fe-O,
O-H stretching vibrations, In addition, the peak at
1624 cm−1 corresponds to the O H bending vibrations. In
the spectra of Fe3O4@IL NPs, the Si-O absorption at
1100 cm−1 can also be observed, and the peaks at 2854.1
and 2,923.6 cm−1 were assigned to C H stretches within
the side alkyl chain of the imidazole ring, indicating that ILs
were successfully bonded to the surface of Fe3O4.
3.2 | Optimization of extraction conditions
To meet a satisfactory recovery rate, the parameters affecting
the recovery of analytes including the amount of adsorbent,
extraction time, sample volume, and desorption conditions
were investigated and optimized. In this research, ultrapure
water spiked with 1 μmol/L of each PAH was used for these
optimization experiments.
3.3 | Effect of the amount of Fe3O4@ILs
The amount of Fe3O4@ILs necessary to afford quantitative
concentration of target analytes is a vital parameter that
determines the recovery rate of the MSPE method. There-
fore, different amounts of Fe3O4@ILs ranging from 10 to
120 mg were tested. As can be seen in Figure 4, the recover-
ies of the PAHs increase with an increase in the amount of
Fe3O4@ILs from 10 to 40 mg, but no obvious change with a
The crystalline structures of different magnetic particles
are investigated using XRD and the results are shown in
Figure 3b. The special reflection peaks at 2θ = 30.2ꢀ, 35.5ꢀ,
43.3ꢀ, 56.6ꢀ, 57.2ꢀ, and 62.8ꢀ can be ascribed to the (220),
FIGURE 2 TEM images of Fe3O4 (a), Fe3O4@ILs (b)
FIGURE 4 Effect of the amount of Fe3O4@ILs

LU ET AL.
5
further increase in the amount. Based on this result, 40 mg
was selected for further experiments.
3.4 | Effect of extraction time and sample volume
To achieve high recovery, an appropriate extraction time is
necessary for Fe3O4@ILs to achieve adsorption equilibrium.
Thus, the effect of extraction time on the recoveries of PAHs
was examined in the range of 2–20 min and the experiment
result is shown in Figure 5a. The recoveries of four PAHs
increase with increasing extraction time for up to 10 min, the
maximum recoveries for PAHs were obtained, indicating
that equilibrium is achieved within 10 min. The efficient dif-
fusion route of nanosized sorbents meets the rapid extraction
dynamics of analytes on the sorbent surface. However, the
recoveries of four PAHs showed a slight decrease when the
extraction time increased to 20 min, this phenomenon may
be attributed to the desorption of PAHs. Acceptable recovery
of target analytes in as large volume of sample solutions as
possible was achieved. In the present study, the investigation
of sample volumes was studied by extracting target analytes,
fixed quantities of 0.1 μmol of each PAHs were added to dif-
ferent sample volumes (50–300 mL). The obtained results
are shown in Figure 5b, a decline of the recoveries was
observed when the sample volume was above 150 mL. This
phenomenon could be due to more loss of the Fe3O4@ILs
sorbent in a large volume solution. Therefore, a sample vol-
ume of 150 mL was selected for further experiments.
FIGURE 6 Effect of the elution solvent (a) and elution time (b) on the
recovery of PAHs
3.6 | Reusability and regeneration
To assess the reusability and regeneration of the Fe3O4@ILs,
reusability tests were carried out by extraction and desorp-
tion for seven consecutive cycles under optimal conditions.
Figure 7 show that the Fe3O4@ILs can be reused up to seven
times without obvious decrease in recoveries of the four
PAHs. These results indicate the good reusability of the
Fe3O4@ILs.
3.7 | Preconcentration performance
Under the optimal extraction conditions, the proposed
method was validated by analyzing 100 mL ultrapure water
samples spiked with PAH standard at the same concentra-
tion. Some quantitative parameters of the proposed method,
such as linear range, correlation coefficients (R2), limits of
detection (LOD), and relative standard deviation (RSD),
were tested and the experiment results are shown in Table 1.
As can be seen, the proposed method has a wide linear range
and good linearities with R2 ranging from 0.9886 to 0.9912
for all analytes were obtained. The LOD, calculated on the
basis of a signal-to-noise ratio (S/N) of 3 for Flu, Ant, Pyr,
and Fla were 2.5, 0.6, 5.8, and 7.2 ng/L, respectively. The
precision of the analytical method was evaluated with five
parallel experiments, and the results indicated that the RSD
(n = 5) for all analytes were less than 5.31%. At a sample
3.5 | Effect of elution solvent and elution time
A suitable eluent should be used to elute PAHs from the
Fe3O4@ILs. Different solvents including methanol, ethanol,
acetonitrile, and isopropanol have been applied to elute all
target analytes. Figure 6a shows that acetonitrile is more
preferable than other organic solvents. Thereby, acetonitrile
was selected as the eluent in this study. The effect of elution
time from 1 to 10 min was studied to improve the recoveries.
The result shown in Figure 6b indicates that the recoveries
of all target analytes increased with increasing elution time
for up to 5 min. However, the recoveries slightly decrease
after 5 min. Consequently, an elution time of 5 min was
enough.
FIGURE 5 Effect of the extraction time (a) and sample volume (b) on the
recovery of PAHs
FIGURE 7 Reusability of Fe3O4@ILs

6
LU ET AL.
TABLE 1 Linear ranges of concentration and detection limits of the PAHs
Analyte
Flu
Linearity curve
Correlation coefficient R2
Linear ranges (nmol/L)
0.3–30
LOD (ng/L)
RSD (%, n = 5)
Y = 5.85X + 0.667
Y = 31.59X − 2.554
Y = 5.52X − 0.441
Y = 4.66X + 0.025
0.9912
0.9907
0.9891
0.9886
2.5
0.6
5.8
7.2
3.62
5.31
2.85
2.25
Ant
0.25–25
Pyr
0.35–35
Fla
0.4–40
volume of 150 mL, the enrichment factors of the proposed
method were about 817, 858, 768, and 699 for Flu, Ant, Pyr,
and Fla, respectively. According to the Drinking Water
Direction of the European Union (98/83/EC) and the Stan-
dards for Drinking Water Quality of China (GB 5749-2006),
the total concentration of PAHs must be less than
100 ng/L[42] Thus, the method used in this study was suffi-
cient for sensitive analysis of the real water samples.
The proposed method with Fe3O4@ILs as sorbents was
also compared to other previous extraction methods that
were used for the determination of PAHs,[10,24,43–45] the
adsorbent amount, loading volume, RSD, LOD, and recover-
ies obtained with different materials are shown in Table 2.
The present method provides that the LOD, RSD, and load-
ing volume are lower or comparable with those previously
reported in the literature.
can be seem in Figure 8b-H, The Flu was detected in
smoked meat, and the concentration was
0.27 μg/kg. Nevertheless, the tested samples were below the
European Commission's maximum level for smoked
meat.[46] The precision of the analytical method was
assessed via the recovery test performed with spiked water
and smoked meat samples. The recoveries of the spiked real
sample were in the range of 80–108% with RSD less than
8.16%. These experimental results indicate that the present
method provides acceptable recoveries and precisions for the
determination of PAHs in environmental water and smoked
meat samples.
4
| CONCLUSIONS
In the present study, a feasible method was developed to pre-
pare Fe3O4@ILs via thiol-ene click reaction. The prepared
Fe3O4@ILs were used as MSPE sorbents for pretreatment of
four PAHs in environmental water and smoked meat sam-
ples before HPLC-UV detection. The result indicates that
the Fe3O4@ILs sorbent offered high extraction efficiencies
and good reusability. Under optimal conditions, the pro-
posed method provides low LOD, good recoveries, high
EFs, and easy operation. Thus, it is expected that the devel-
oped method can be used as a convenient and efficient
extraction and enrichment technique for trace PAHs from
environmental water and smoked meat samples.
3.8 | Analysis of the environmental water samples
To further validate the practical performance of the present
method, the prepared Fe3O4@IL NPs were utilized for the
determination of PAH concentration in environmental water
and smoked meat samples including river, tap, wastewaters,
and smoked meat. The results of the spiked real samples are
shown in Table 3. These four PAHs were not detected in
Longjiang river water, tap water, and wastewater. Figure 8a
shows the HPLC chromatogram of the spiked water samples
before and after MSPE using Fe3O4@ILs. As can be seem
from Figure 8a-B,D,F, four peaks of the target analytes were
observed in the chromatogram after extraction of PAHs from
the spiked water sample. However, no peaks were observed
before extraction of PAHs from the spiked water sample.
This result indicated that the Fe3O4@ILs can act as sorbents
for enrichment of PAHs in water samples. Figure 8b shows
the HPLC chromatogram of the smoked meat sample and
the spiked smoked meat sample with and without MSPE. As
ACKNOWLEDGMENTS
This work was financially supported by the Guangxi Natural
Science Foundation of China (nos. 2018GXNSFAA138140,
2014GXNSFBA118045,
2015GXNSFAA139030,
and
2017GXNSFAA198118), the higher-level talent scientific
research projects funded start-up funds of Hechi University
TABLE 2 Comparison of the present method with other methods for determination of PAHs in water samples
Instrumental
technique
Sorbent
amount (mg)
Loading
volume (mL)
LOD
(ng/L)
Recovery
(%)
Sorbent
RSD (%)
4.73–8.09
3.9–6.9
4–8.9
Reference
[10]
Cotton fiber
HPLC-FLD
HPLC-FLD
GC–MS
—
80
30
50
40
50
40
50
0.1–2.00
0.33–8.3
40–1,110
800–36,000
90–190
70.69–110
76–105
75–102
35–99
Fe3O4@ C16mimBr
Fe3O4@ILs
300
100
20
[24]
[12]
Fe3O4@C18
GC–MS
2–10
[43]
Fe3O4@graphene
Fe3O4@ag/b-TMPDTPA
Fe3O4@ILs
HPLC-UV
HPLC-UV
HPLC-UV
50
1.7–11.7
2.6–8.3
2.25–8.16
77–103
82.4–109
80–108
[44]
100
150
20–100
[45]
0.6–7.2
This work

LU ET AL.
7
TABLE 3 Recoveries of the PAHs in real samples (n = 3)
Spiked concentration
2.5 nmol/L
5.0 nmol/L
10.0 nmol/L
Matrix
Analyte
Flu
Recovery (%)
RSD (%)
3.62
3.77
2.25
2.85
6.1
Recovery (%)
RSD (%)
5.31
4.29
3.86
4.12
5.57
3.49
4.06
4.95
4.19
4.86
5.32
7.76
3.93
5.54
4.11
5.65
Recovery (%)
RSD (%)
2.85
3.91
5.33
4.63
5.05
3.38
4.86
3.51
6.75
8.16
4.68
6.95
6.07
6.25
6.73
7.58
Longjiang water
84
80
89
88
80
92
83
81
104
87
91
89
95
98
87
91
86
87
83
92
92
104
91
90
88
90
84
94
97
92
102
95
105
102
106
98
Ant
Pyr
Fla
Tap water
Flu
89
Ant
Pyr
Fla
4.66
3.67
3.73
5.07
3.97
4.81
5.43
5.27
4.97
4.81
3.88
93
96
95
Wastewater
Smoked meat
Flu
96
Ant
Pyr
Fla
108
92
105
101
107
93
Flu
Ant
Pyr
Fla
102
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1 nmol/L ant, 5 nmol/L flu, Pyr and flu) without MSPE (A, C, E) and with
MSPE (B, D, F). Longjiang River water sample (A, B); tap water (C, D);
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How to cite this article: Lu J, Lu S, Yao D,
Huang X, Lai H, Yin X. Preparation of ionic liquid-
modified magnetic nanoparticles based on thiol-ene
click chemistry for the analysis of polycyclic aromatic
hydrocarbons in water and smoked meat samples.
J Chin Chem Soc. 2019;1–8. https://doi.org/10.1002/
jccs.201800377
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