Co-reporter:Yanan Yuan, Xiaoyan Jiao, Yehong Han, Ligai Bai, Haiyan Liu, Fengxia Qiao, Hongyuan Yan
Food Chemistry 2017 Volume 230(Volume 230) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.foodchem.2017.03.012
•A simple and time-saving one-pot synthesis for preparation of EGC is developed.•EGC possess a three-dimensional framework structure for avoiding agglomeration.•EGC is successfully used for isolation and determination of clenbuterol in pork.•Good extraction and purification efficiency over other adsorbents.A fluffy porous ethylenediamine-connected graphene/carbon nanotube composite (EGC), prepared by a simple and time-saving one-pot synthesis, was successfully applied as an adsorbent in pipette-tip solid-phase extraction (PT-SPE) for the rapid extraction and determination of clenbuterol (CLB) from pork. In the one-pot synthesis, carbon nanotubes were inserted into graphene sheets and then connected with ethylenediamine through chemical modification to form a three-dimensional framework structure to prevent agglomeration of the graphene sheets. Under the optimum conditions for extraction and determination, good linearity was achieved for CLB in the range of 15.0–1000.0 ng g−1 (r = 0.9998) and the recoveries at three spiked levels were in the range of 92.2–96.2% with relative standard deviation ≤9.2% (n = 3). In comparison with other adsorbents, including silica, NH2, C18, and Al2O3, EGC showed higher extraction and purification efficiency for CLB from pork samples. This analytical method combines excellent adsorption performance of EGC and high extraction efficiency of PT-SPE.
Co-reporter:Zan Li, Jun Jia, Mingwei Wang, Hua Zhang, Hongyuan Yan, Fengxia Qiao
Journal of Chromatography A 2017 Volume 1529(Volume 1529) pp:
Publication Date(Web):22 December 2017
DOI:10.1016/j.chroma.2017.10.074
•C8-AMS has two main functional groups which improved its selectivity.•An environmental friendly method for C8-AMS synthesis was provided.•A C8-AMS-SPE method was developed for extraction of triazines in watermelon.A C8-and-amino-bifunctionalized ordered mesoporous organosilica (C8-AMS) was prepared in a deep eutectic solvent—a green solvent—that was used as the reaction medium for this procedure instead of organic solvents or other catalyst for the first time. This method provided a nontoxic way for C8 grafting and obtaining an ordered mesoporous organosilica material with both hydrophilic and hydrophobic groups. Besides advantages such as its large surface area, regular and uniform pore size, and hydrothermal stability, the obtained bifunctionalized C8-AMS also have two main functional groups in the obtained structure, C8 and amino, which enriched the adsorption mechanism of the material and as a result improved the adsorption selectivity of C8-AMS. Its performance as an adsorbent was estimated in extracting trace triazine herbicides from watermelon using solid-phase extraction (SPE) followed by high-performance liquid chromatography (HPLC). The proposed method provided satisfactory features in terms of linearity (0.01–2.00 μg g−1), limits of detection (2.9–5.1 ng g−1), accuracy (recovery: 85.7–101.7%), and precision (intra-day and inter-day RSDs: 1.68–2.60% and 3.05–4.01%).
Co-reporter:Jiankun Cao, Hongyuan Yan, Shigang Shen, Ligai Bai, Haiyan Liu, Fengxia Qiao
Analytica Chimica Acta 2016 Volume 943() pp:136-145
Publication Date(Web):2 November 2016
DOI:10.1016/j.aca.2016.09.016
•New hydrophilic molecularly imprinted monolithic resin (MIMR) is synthesized.•MIMR presents special recognition to plant growth regulators in aqueous matrices.•Monolithic structures avoid the drawbacks associated with uneven filling.•Dummy template eliminates the influence of template leakage on quantitative analysis.New hydrophilic molecularly imprinted melamine-urea-formaldehyde monolithic resin (MIMR) is synthesized using dopamine hydrochloride as a dummy template via in-situ polymerization directly within pipette tips and it presents special molecular recognition to plant growth regulators in aqueous matrices. Hydrophilic groups (such as hydroxyl groups, imino groups, and amino groups) can be introduced into MIMR by melamine– urea–formaldehyde resin, which make MIMR materials compatible with aqueous media and show their specific molecular recognition in aqueous sample solutions. Meanwhile, monolithic structures avoid the influence of uneven filling on the extraction efficiency. Various parameters affecting the selective recognition of MIMR have been optimized, such as molar ratio of melamine to urea, molar ratio of melamine and urea to formaldehyde, the amount of template and porogen. The prepared MIMR is applied as the sorbents of solid phase extraction (SPE) for sensitive and selective recognition of three plant growth regulators (p-chlorophenoxyacetic acid, 1-naphthaleneacetic acid and 2.4-dichlorophenoxyacetic acid) in bean sprouts. Considering its excellent hydrophilicity and specificity, MIMR–SPE is promising to be a potential pretreatment strategy in biological, environmental, and clinical fields.
Co-reporter:Lu Wang, Hongyuan Yan, Chunliu Yang, Zan Li, Fengxia Qiao
Journal of Chromatography A 2016 Volume 1456() pp:58-67
Publication Date(Web):22 July 2016
DOI:10.1016/j.chroma.2016.06.010
•Mimic molecularly imprinted ordered mesoporous silica adsorbents are prepared.•4,4′-Sulfonyldiphenol and (3-isocyanatopropyl) triethoxysilane used as template and monomer.•Pipette-tip solid-phase extraction coupled with liquid chromatography detection of estradiol.•Trace level of estradiol in milk samples were rapidly extracted and isolated.A mimic molecularly imprinted ordered mesoporous silica (MIOMS) adsorbent was prepared utilizing a thermally reversible semicovalent approach. The thermally reversible covalent template-monomer complex was firstly synthesized by employing 4,4′-sulfonyldiphenol (BPS) and (3-isocyanatopropyl) triethoxysilane (ICPTES) as template and monomer, respectively. The template-monomer complex was incorporated into ordered mesoporous silica via a simple self-assembly process. The adsorption experiment illustrated that the imprint-removed silica (MIOMS-ir) had higher special recognition ability (250 μg g−1) for estradiol (E2) than the non-imprinted silica (NIOMS-ir) (25 μg g−1). MIOMS-ir was applied as an adsorbent in pipette-tip solid-phase extraction (PT-SPE) coupled with liquid chromatography-fluorescence detector (LC-FLD) for determination of E2 in milk samples. Under the optimized conditions, only 3 mg of the adsorbent, 0.3 mL of water as washing solvent, and 0.5 mL of acetonitrile-acetic acid (96:4, v/v) as elution solvent were used in the pretreatment procedure of milk samples. Good calibration linearity was obtained in a range of 25 ng L−1 to 1000 ng L−1, and the recoveries at three spiked levels were ranged from 95.4% to 107.0% with relative standard deviations (RSDs) ≤3.1% (n = 3). The proposed MIOMS-ir-PT-SPE-LC-FLD method combined the advantages of PT-SPE and ordered mesoporous material such as ease assembly, low cost, high extraction efficiency and large specific surface area, so it is a potential pretreatment strategy for the extraction and determination of E2 in complex milk samples.
Co-reporter:Mingyu Wang, Xiaochen Chang, Xingyu Wu, Hongyuan Yan, Fengxia Qiao
Journal of Chromatography A 2016 Volume 1458() pp:9-17
Publication Date(Web):5 August 2016
DOI:10.1016/j.chroma.2016.06.047
⬢Water-compatible dummy molecularly imprinted resin (MIR) is synthesized in aqueous matrix.⬢MIR shows excellent molecular recognition in aqueous matrices.⬢No organic solvent used in the entire MIR-mini-SPE procedure.⬢Green miniaturized solid-phase extraction is developed applied to plant growth regulators.A water-compatible dummy molecularly imprinted resin (MIR) was synthesized in water using melamine, urea, and formaldehyde as hydrophilic monomers of co-polycondensation. A triblock copolymer (PEO-PPO-PEO, P123) was used as porogen to dredge the network structure of MIR, and N-(1-naphthyl) ethylenediamine dihydrochloride, which has similar shape and size to the target analytes, was the dummy template of molecular imprinting. The obtained MIR was used as the adsorbent in a green miniaturized solid-phase extraction (MIR⬜mini-SPE) of plant growth regulators, and there was no organic solvent used in the entire MIR⬜mini-SPE procedure. The calibration linearity of MIR⬜mini-SPE⬜HPLC method was obtained in a range 5⬜250 ng mL↙1 for IAA, IPA, IBA, and NAA with correlation coefficient (r) Ⱕ0.9998. Recoveries at three spike levels are in the range of 87.6⬜100.0% for coconut juice with relative standard deviations Ⱔ8.1%. The MIR⬜mini-SPE method possesses the advantages of environmental friendliness, simple operation, and high efficiency, so it is potential to apply the green pretreatment strategy to extraction of trace analytes in aqueous samples.
Co-reporter:Huanhuan Chen, Yanan Yuan, Can Xiang, Hongyuan Yan, Yehong Han, Fengxia Qiao
Journal of Chromatography A 2016 Volume 1474() pp:23-31
Publication Date(Web):25 November 2016
DOI:10.1016/j.chroma.2016.10.076
•Graphene and carbon nanotube is assembled to three-dimensional material.•Ionic liquid introduce ionic exchange and electrostatic interactions to the material.•Rapid determination of thiochromanones anticancer active compound in urine.A new type of amine-terminated-ionic-liquid-functionalized graphene/multi-walled carbon nanotubes hybrid material (IL-G/MWCNTs) was synthesized and used as an adsorbent in miniaturized pipette tip solid-phase extraction (PT-SPE) coupled with liquid chromatography for the isolation and determination of (Z)–3–(chloromethylene)–6–fluorothiochroman–4–one (CMFT) in urine. Parameters for the preparation of IL-G/MWCNTs and the PT-SPE procedure, including the mass ratio of graphene oxide and oxidized multi-walled carbon nanotubes, the mass ratio of graphene oxide and the ionic liquid, and the type and volume of washing and elution solvents were optimized to achieve higher extraction efficiency. Good linearity of the method was achieved in the range 0.03–5.0 μg mL−1 with a coefficient of determination (r2) of 0.9999. The limits of detection and quantification were 0.009 and 0.030 μg mL−1, respectively. The intra- and inter-day precisions, expressed as relative standard deviations (RSDs), were evaluated by performing replicate analyses of samples spiked at 0.1 μg mL−1 on the same day (n = 6) and over three consecutive days, and were 4.8 and 5.5%, respectively. Recoveries between 73.9 and 93.9% were obtained at three spiking levels, with RSDs ≤ 7.9%. Five batches of the adsorbent were investigated to confirm the reliability of the preparation method.
Co-reporter:Tianwei Lv, Hongyuan Yan, Jiankun Cao, and Shiru Liang
Analytical Chemistry 2015 Volume 87(Issue 21) pp:11084
Publication Date(Web):October 6, 2015
DOI:10.1021/acs.analchem.5b03253
Hydrophilic molecularly imprinted resorcinol–formaldehyde–melamine resin (MIRFM) is synthesized in water and shows excellent molecular recognition in aqueous matrices. The double functional monomers resorcinol and melamine, and the cross-linker formaldehyde, are all hydrophilic, and then the hydrophilic groups (such as hydroxyls, imino groups, and ether linkages) can be introduced into MIRFM, which make the material compatible with aqueous samples. The general principle is demonstrated by the synthesis of MIRFM using sulfanilamide as a dummy template for the selective recognition to sulfonamides (SAs) in milk samples. Resorcinol and melamine can interact with the template mainly by hydrogen bonding and π–π interaction, which makes MIRFM and the analytes have strong affinity. Besides, melamine can improve the rigidity of MIRFM and accelerate the polymerization process, so there is no need to add base or acid as a catalyst, which guarantees the success of molecular imprinting. MIRFM shows higher recovery and improved purification effect for SAs, in comparison to silica, HLB, C18, and SCX. Because of its excellent hydrophilicity and specificity, MIRFM is promising to be applied in biological, environmental, and clinical fields.
Co-reporter:Yunyun Sun, Jing Tian, Lu Wang, Hongyuan Yan, Fengxia Qiao, Xiaoqiang Qiao
Journal of Chromatography A 2015 Volume 1422() pp:53-59
Publication Date(Web):27 November 2015
DOI:10.1016/j.chroma.2015.10.035
•One pot synthesis of magnetic graphene/carbon nanotube composites (M-G/CNTs) was developed.•CNTs and Fe3O4 nanoparticles acted as spacer insert between the layers of graphene.•Magnetic dispersive solid-phase extraction (MDSPE) method was developed.•Combine the excellent adsorption ability of M-G/CNTs and rapid extraction efficiency of MDSPE.•Rapid extraction and determination of oxytetracycline (OTC) in sewage water.A simple and time-saving one pot synthesis of magnetic graphene/carbon nanotube composites (M-G/CNTs) was developed that could avoid the tedious drying process of graphite oxide, and G/CNTs were modified by Fe3O4 nanoparticles in the reduction procedure. It contributed to a shorten duration of the synthesis process of M-G/CNTs. The obtained M-G/CNTs were characterized and the results indicated that CNTs and Fe3O4 nanoparticles were served as spacer distributing to the layers of graphene, which was beneficial for enlarging surface area and improving extraction efficiency. Moreover, M-G/CNTs showed good magnetic property and outstanding thermal stability. Then M-G/CNTs were applied as adsorbent of magnetic dispersive solid-phase extraction for rapid extraction and determination of oxytetracycline in sewage water. Under the optimum conditions, good linearity was obtained in the range of 20–800 ng mL−1 and the recoveries were ranged from 95.5% to 112.5% with relative standard deviations less than 5.8%.
Co-reporter:Chen Yang, Tianwei Lv, Hongyuan Yan, Gaochan Wu, and Haonan Li
Journal of Agricultural and Food Chemistry 2015 Volume 63(Issue 43) pp:9650-9656
Publication Date(Web):October 8, 2015
DOI:10.1021/acs.jafc.5b02762
A new kind of glyoxal–urea–formaldehyde molecularly imprinted resin (GUF-MIR) was synthesized by a glyoxal–urea–formaldehyde (GUF) gel imprinting method with 4,4′-dichlorobenzhydrol as a dummy template. The obtained GUF-MIR was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) and applied as a selective adsorbent of miniaturized pipet tip solid-phase extraction (PT-SPE) for the separation and extraction of three organochlorine pesticides (dicofol (DCF), dichlorodiphenyl dichloroethane (DDD), and tetradifon) in spinach samples. The proposed pretreatment procedures of spinach samples involved only 5.0 mg of GUF-MIR, 0.7 mL of MeOH–H2O (1:1, v/v) (washing solvent), and 0.6 mL of cyclohexane–ethyl acetate (9:1, v/v) (elution solvent). In comparison with other adsorbents (such as silica gel, C18, NH2–silica gel, and neutral alumina (Al2O3–N)), GUF-MIR showed higher adsorption and purification capacity for DCF, DDD, and tetradifon in aqueous solution. The average recoveries at three spiked levels ranged from 89.1% to 101.9% with relative standard deviations (RSDs) ≤ 7.1% (n = 3). The presented GUF-MIR-PT-SPE method combines the advantages of molecularly imprinted polymers (MIPs), GUF, and PT-SPE and can be used in polar solutions with high affinity and selectivity to the analytes in complex samples.
Co-reporter:Mingyu Wang;Yanan Yuan;Yehong Han
Analytical and Bioanalytical Chemistry 2015 Volume 407( Issue 4) pp:1231-1239
Publication Date(Web):2015 February
DOI:10.1007/s00216-014-8336-0
A pipette-tip solid-phase extraction (PT–SPE) method using a sol–gel hybrid adsorbent has been developed. The method could be used for rapid screening of vegetable matrices for cyanazine and atrazine; assay of cucumbers is reported as an example. The sol–gel hybrid adsorbent was synthesized from tetraethyl orthosilicate (TEOS) as the precursor and γ-(methacryloyloxy)propyltrimethoxysilane (KH570) as both surface modifying agent and monomer for the polymerization. Under the optimized conditions, good calibration linearity was obtained in the range 0.022–1.65 μg g−1 with correlation coefficients (r) ≥0.9996. Recovery at three spike levels ranged from 87.6 to 93.8 % with relative standard deviations ≤7.8 %. This extraction strategy has several advantages, for example ease of assembly, low cost, and high extraction efficiency, and is a potential pretreatment strategy for rapid screening of cyanazine and atrazine in vegetables.
Co-reporter:Ruiling Wang;Yanan Yuan;Xun Yang;Yehong Han
Microchimica Acta 2015 Volume 182( Issue 13-14) pp:2201-2208
Publication Date(Web):2015 October
DOI:10.1007/s00604-015-1544-2
Microparticles were synthesized by suspension copolymerization of the synthetic ionic liquid (IL) 1-allyl-3-methyl-imidazolium bromide with ethylene glycol dimethacrylate. The particles have a regular spherical shape and an average diameter of 65 ± 24 μm. Their affinity for the fluoroquinolone antibiotics ofloxacin (OFL), lomefloxacin (LOM) and ciprofloxacin (CIP) is much higher than that of the blank polymer (not containing an IL), of polymers using methacrylic acid as functional monomer, of hydrophilic-lipophilic balanced sorbents, and of C18 sorbents. The microparticles were applied to the solid-phase extraction and rapid preconcentration of the fluoroquinolones from urine which then were quantified by HPLC. The calibration plot covers the 0.05 to 20 μg mL−1 concentration range, and the average recoveries at three spiking levels range from 93.6 to 103.7 %, with RSD of ≤5.7 %. The method was successfully applied to the determination of fluoroquinolones in spiked urine.
Co-reporter:Hongyuan Yan, Ning Sun, Shijia Liu, Kyung Ho Row, Yanxue Song
Food Chemistry 2014 Volume 158() pp:239-244
Publication Date(Web):1 September 2014
DOI:10.1016/j.foodchem.2014.02.089
•A miniaturized graphene-based pipette tip extraction (M-G-PTE) was proposed by using 3.0 mg graphene adsorbent.•The M-G-PTE device is simple and economic and could handle 2.0 mL milk sample at one time.•The M-G-PTE-HPLC method was developed to analyze the residues of SAs in milk samples.•The most of sample matrix interference was eliminated and the analytes were isolated effectively.A miniaturized graphene-based pipette tip extraction (M-G-PTE) method coupled with liquid chromatography-ultraviolet detection was developed for rapid screening of sulfadimidine, sulfachloropyridazine, sulfamonomethoxine, and sulfachloropyrazine residues in bovine milk. Because of the large surface area and unique chemical structure of graphene, an M-G-PTE device packed with 3.0 mg graphene could handle 2.0 mL of milk samples at one time. This M-G-PTE device showed better adsorption performance for sulfonamides (SAs) than those packed with other adsorbents such as C18, HLB, SCX, PCX, and multiwalled carbon nanotubes. Under the optimized conditions, good linearity was obtained in the range of 0.05–6.0 μg g−1, with a correlation coefficient (r2) of ⩾0.9991. The recoveries at three spiking levels ranged from 90.1% to 113.5% with relative standard deviations (RSDs) of ⩽3.9%. The proposed M-G-PTE method was simple, economical, sensitive, and produced less organic pollution. Thus, it could be applied to the rapid screening of SAs in complicated bovine milk samples.
Co-reporter:Hongyuan Yan, Chen Yang, Yunyun Sun, Kyung Ho Row
Journal of Chromatography A 2014 Volume 1361() pp:53-59
Publication Date(Web):26 September 2014
DOI:10.1016/j.chroma.2014.07.102
•Ionic liquid molecularly imprinted pipette-tip solid-phase extraction is developed.•1-Allyl-3-methylimidazolium bromide is used as auxiliary solvent.•Miniature device of pipette tip solid-phase extraction is self-assembled.•The IL–MIPs adsorbents in PT-SPE are only 2.0 mg.•Dicofol is rapidly isolated and extracted from celery.A new type of ionic liquid molecularly imprinted polymers (IL–MIPs) synthesized by precipitation polymerization using 1-allyl-3-methylimidazolium bromide as an auxiliary solvent and α-chloro-dichlorodiphenyltrichloroethane (α-chloro-DDT) as the template was applied as a selective sorbent of minimized pipette tip-solid-phase extraction (PT-SPE) for rapid isolation and extraction of dicofol (DCF) from celery samples. The pretreatment procedure of celery samples involved only 2.0 mg of IL–MIPs, 0.8 mL of acetonitrile–water (ACN–H2O; 1:1, v/v) (washing solvent), and 1.0 mL of acetone–10% acetic acid (HOAc) (elution solvent). Compared with molecularly imprinted polymers (MIPs), ionic liquid–non-imprinted polymers (IL–NIPs) and conventional sorbents such as C18, Si, NH2, and Al2O3–N, IL–MIPs showed higher adsorption and purification capacity to DCF in aqueous solution. Good linearity for DCF was observed in the range from 2.3 to 232.5 ng g−1 (r2 = 0.9995). The average recoveries at three spiking levels ranged from 86.6% to 101.9% with relative standard deviations (RSDs) of ≤6.5% (n = 3). The presented IL–MIPs–PT-SPE–GC/ECD method combines the advantages of MIPs, IL, and PT-SPE, and can be used in aqueous conditions with high affinity and selectivity to analytes of complex samples.
Co-reporter:Hongyuan Yan, Mingyu Wang, Yehong Han, Fengxia Qiao, Kyung Ho Row
Journal of Chromatography A 2014 Volume 1346() pp:16-24
Publication Date(Web):13 June 2014
DOI:10.1016/j.chroma.2014.04.045
•New hybrid dummy molecularly imprinted polymers.•3-Aminopropyltriethoxy silane-methacrylic acid as hybrid monomer.•Miniaturized molecularly imprinted solid-phase extraction in 1.5-mL tapered centrifuge tube.•Good recognition and selective extraction of acyclovir from urine.The miniaturized molecularly imprinted solid-phase extraction (mini-MISPE) coupled with high-performance liquid chromatography was proposed for the determination of acyclovir in urine. 1.5-mL tapered plastic centrifuge tube filled with hybrid molecularly imprinted polymers (HMIPs) was used as the cartridge of mini-MISPE, and the HMIPs synthesized with 3-aminopropyltriethoxy silane-methacrylic acid as monomer exhibited good recognition and selectivity for acyclovir. Under the optimized condition, good linear calibration was obtained in a range of 0.5–15 μg mL−1 with the correlation coefficient of 0.9994, and the recoveries at three spiked levels were 91.6–103.3% in urine with the relative standard deviation (RSD) of ≤3.5%. Excellent intra-day and inter-day repeatability were achieved with RSD of ≤2.6% and 4.0% in three different concentrations. This method combined the advantages of HMIPs and mini-MISPE, and it could become an alternative tool for analyzing the residues of acyclovir in complex urine matrices.
Co-reporter:Lihui Wang, Mingyu Wang, Hongyuan Yan, Yanan Yuan, Jing Tian
Journal of Chromatography A 2014 Volume 1368() pp:37-43
Publication Date(Web):14 November 2014
DOI:10.1016/j.chroma.2014.09.059
•Graphene oxide/polypyrrole foam materials.•Pipette tip solid-phase extraction.•High adsorption and purification capacity to auxins in papaya juice.•Good sensitivity and effective extraction of auxins.A new material, graphene oxide/polypyrrole (GO/Ppy), was synthesized by mixing graphene oxide and polypyrrole in a specific proportion. It possesses a unique structure similar to that of foam. A homemade pipette-tip solid-phase extraction (PT-SPE) device, which is more simple and convenient than traditional devices, was used for saving reagents and operation time. When GO/Ppy was used as the adsorbent of PT-SPE for determining three auxins (indole-3-propionic acid, indole-3-butyric acid, and 1-naphthaleneacetic acid) present in trace amounts in papaya juice, it showed high affinity and adsorption capacity for all the three auxins. GO/Ppy-PT-SPE also had a significant capacity for eliminating the interferences from the papaya juice matrix. Under optimized conditions, a good linearity of auxins was obtained in the range 16.3–812.5 ng g−1; the average recoveries at the three spiked levels of the three auxins ranged from 89.4% to 105.6% with the relative standard deviations ≤3.0%. Meanwhile, six papaya juice samples with different growth stages were analyzed under optimum conditions, and trace auxins in the range 18.3–100.6 ng g−1 were observed. Because of its high selectivity, simplicity, and reliability, the GO/Ppy-PT-SPE method developed herein can be potentially applied for determining trace auxins in complex biological samples.
Co-reporter:Xiaoling Cheng, Hongyuan Yan, Xiaoling Wang, Ning Sun, Xiaoqiang Qiao
Food Chemistry 2014 Volume 162() pp:104-109
Publication Date(Web):1 November 2014
DOI:10.1016/j.foodchem.2014.04.023
•Simple and rapid vortex-assisted magnetic dispersive solid-phase microextraction.•Magnetic dummy imprinted microspheres synthesised by aqueous suspension polymerisation.•Selective screening and recognition of dicofol in tea products.•Extraction efficiency was markedly increased with reduced equilibrium time.A simple and rapid vortex-assisted magnetic dispersive solid-phase microextraction (VAMDSME) method coupled with gas chromatography-electronic capture detection was developed for rapid screening and selective recognition of dicofol in tea products. The magnetic molecularly imprinted microspheres (mag-MIMs) synthesised by aqueous suspension polymerisation using dichlorodiphenyltrichloroethane (DDT) as a dummy template showed high selectivity and affinity to dicofol in aqueous solution and were successfully applied as special adsorbents of VAMDSME for rapid isolation of dicofol from complex tea matrix. Good linearity was obtained in a range of 0.2–160 ng g−1 and the limit of detection based on a signal to noise ratio of 3 was 0.05 ng g−1. The recoveries at three spiked levels ranged from 83.6% to 94.5% with the related standard deviations (RSD) ⩽ 5.0%. The VAMDSME-GC protocol, which took advantages of the selective adsorption of molecularly imprinted microspheres and rapid magnetic phase separation, as well as the short equilibrium time by vortex-assisted, could avoid the time-consuming procedures related to other traditional extraction methods.
Co-reporter:Jindong Qiao, Mingyu Wang, Hongyuan Yan, and Gengliang Yang
Journal of Agricultural and Food Chemistry 2014 Volume 62(Issue 13) pp:2782-2789
Publication Date(Web):March 12, 2014
DOI:10.1021/jf4051705
A new magnetic dummy molecularly imprinted dispersive solid-phase extraction (MAG-MIM-dSPE) coupled with gas chromatography-FID was developed for selective determination of phthalates in plastic bottled beverages. The new magnetic dummy molecularly imprinted microspheres (MAG-MIM) using diisononyl phthalate as a template mimic were synthesized by coprecipitation coupled with aqueous suspension polymerization and were successfully applied as the adsorbents for MAG-MIM-dSPE to extract and isolate five phthalates from plastic bottled beverages. Validation experiments showed that the MAG-MIM-dSPE method had good linearity at 0.0040–0.40 μg/mL (0.9991–0.9998), good precision (3.1–6.9%), and high recovery (89.5–101.3%), and limits of detection were obtained in a range of 0.53–1.2 μg/L. The presented MAG-MIM-dSPE method combines the quick separation of magnetic particles, special selectivity of MIM, and high extraction efficiency of dSPE, which could potentially be applied to selective screening of phthalates in beverage products.
Co-reporter:Ning Sun, Yehong Han, Hongyuan Yan, Yanxue Song
Analytica Chimica Acta 2014 810() pp: 25-31
Publication Date(Web):31 January 2014
DOI:10.1016/j.aca.2013.12.013
•Miniaturized pipette tip graphene solid-phase extraction was developed.•Cartridge was assembled by 1.0 mg of graphene as sorbent in a small pipette tip.•Graphene was synthesized by a modified method without a drying procedure.•Comparative studies showed that graphene is superior to other commercial sorbents.A sensitive, economical, and miniaturized self-assembly pipette tip graphene solid-phase extraction (PT-G-SPE) coupled with liquid chromatography fluorescence detection (LC-FD) was developed for rapid extraction and determination of three sulfonamide antibiotics (SAs) in environmental water samples. The PT-G-SPE cartridge, assembled by packing 1.0 mg of graphene as sorbent into a 100 μL pipette tip, showed high adsorption capacity for the SAs owing to the large surface area and unique structure of graphene. The factors that affected the extraction efficiency of PT-G-SPE, including sample volume, pH, sorbent amount, washing solvent and eluent solvent were optimized. Good linearity for SAs was obtained in a range of 2–4000 pg mL−1 with correlation coefficients (r2) ≥ 0.9993. The recoveries of the SAs at three spiked levels ranged from 90.4% to 108.2% with relative standard deviations (RSD) ≤ 6.3%. In comparison with other sorbents such as C18, HLB, SCX, PCX, and multiwalled carbon nanotubes, one advantage of using graphene as sorbent of pipette tip solid-phase extraction (PT-SPE) was that PT-G-SPE could adsorb larger sample volume (10 mL) at a small amount of sorbent (1 mg) and low solvent consumption with good extraction efficiency, which not only increased the fraction of analytes to LC and the sensitivity of SAs determination, but also reduced the cost and pollution.
Co-reporter:Xun Yang, Ruiling Wang, Weihua Wang, Hongyuan Yan, Mande Qiu, Yanxue Song
Journal of Chromatography B 2014 Volumes 945–946() pp:127-134
Publication Date(Web):15 January 2014
DOI:10.1016/j.jchromb.2013.11.040
•Novel molecularly imprinted organic-inorganic hybrid polymer.•High mechanical strength and special affinity to target analytes.•Selective isolation and determination of fluoroquinolones in tilapia.•High extraction and purification efficiency in polar solution.A novel molecularly imprinted organic–inorganic hybrid polymer (MI-MAA/APTS) based on a dummy molecular imprinting technique and an organic–inorganic hybrid material technique was synthesised and used as a sorbent in solid-phase extraction for the selective isolation and determination of ofloxacin (OFL), lomefloxacin (LOM), and ciprofloxacin (CIP) in tilapia samples. The MI-MAA/APTS sorbent was prepared from 3-aminopropyltriethoxysilanes (APTS) as an inorganic source and methacrylic acid (MAA) as an organic source and exhibited high mechanical strength and special affinities to the analytes. A comparison of MI-MAA/APTS with other conventional sorbents (C18 and HLB) showed that MI-MAA/APTS displayed good selectivity and affinity for OFL, LOM, and CIP, and the recoveries of the analytes at three spiked levels were in the range of 85.1–101.0%, with the relative standard deviations ≤5.1%. The presented MI-MAA/APTS-SPE–HPLC method could be potentially applied to the determination of fluoroquinolones (FQs) in complex fish samples.
Co-reporter:Hongyuan Yan;Mengmeng Gao;Chen Yang;Mande Qiu
Analytical and Bioanalytical Chemistry 2014 Volume 406( Issue 11) pp:2669-2677
Publication Date(Web):2014 April
DOI:10.1007/s00216-014-7665-3
Ionic liquid-modified magnetic polymeric microspheres (ILMPM) were prepared based on Fe3O4 magnetic nanoparticles (MNPs) and ionic liquids (ILs) incorporated into a polymer. The composites were characterized using scanning electron microscopy, Fourier transform infrared analysis, thermogravimetric analysis, X-ray diffraction, and vibrating magnetometer, which indicated that ILMPM had a regularly spherical shape and strong magnetic property. The obtained ILMPM were successfully applied as a special adsorbent of magnetic dispersive solid phase extraction (MDSPE) for the rapid extraction and isolation of sulfamonomethoxine sodium and sulfachloropyrazine sodium in urine. The factors that affected extraction efficiency, such as adsorption conditions, desorption conditions, washing and elution solvents, and pH of the sample solution, were optimized. Under the optimum condition, good linearity in the range of 0.005–2.0 μg g−1 (r ≥ 0.9996) was obtained for the two sulfonamides (SAs); the average recoveries at three spiked levels ranged from 86.9 to 102.1 %, with relative standard deviations of ≤4.3 %. The presented ILMPM-MDSPE method combined the advantages of ILs, MNPs, and MDSPE and therefore could be potentially applied for rapid screening of SAs in urine.
Co-reporter:Hongyuan Yan, Ning Sun, Yehong Han, Chen Yang, Mingyu Wang, Ruijun Wu
Journal of Chromatography A 2013 Volume 1307() pp:21-26
Publication Date(Web):13 September 2013
DOI:10.1016/j.chroma.2013.07.054
•A simple and rapid IL-MIPs-SPE-GC method for determination of dicofol from vegetables.•MIPs prepared by ionic liquid as auxiliary solvent and α-chloro-DDT as dummy template show high affinity to dicofol.•Rapid screening of dicofol from vegetables and the interferences from sample matrix were eliminated.•Extraction efficiency was markedly increased with reduced equilibrium time.•This method improved the selectivity and eliminated the effect of template leakage on quantitative analysis.New ionic liquid-mediated molecularly imprinted polymers (IL-MIPs) were prepared by precipitation polymerization using 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM+PF6−) as the auxiliary solvent, α-chloro-DDT as the dummy template, and they were successfully applied as the sorbents of solid-phase extraction (SPE) for rapid screening of dicofol from cabbage, tomato, and carrot samples. The IL-MIPs were characterized by FTIR, FE-SEM, static adsorption and chromatographic evaluation, and the results revealed that the IL-MIPs had higher adsorption capacity and selectivity to dicofol in aqueous solution than that of ionic liquid-mediated non-imprinted polymers (IL-NIPs) and non-imprinted polymers (NIPs). Under the optimized conditions, the IL-MIPs-SPE-GC method offered good linearity (0.4–40.0 ng g−1, r2 = 0.9995) and the average recoveries of dicofol at three spiked levels were in a range of 84.6–104.1% (n = 3) with RSD ≤ 7.6%. The proposed method obviously improved the selectivity and purification effect, and eliminated the effect of template leakage on dicofol quantitative analysis.
Co-reporter:Hongyuan Yan, Hui Wang
Journal of Chromatography A 2013 Volume 1295() pp:1-15
Publication Date(Web):21 June 2013
DOI:10.1016/j.chroma.2013.04.053
•The updated advancements made in DLLME were discussed.•Expansion of DLLME by ionic liquids and low-density organic solvents was summarised.•The combination of DLLME with other extraction techniques was illustrated.•Recent applications of DLLME in environmental, food and biological fields were summarised.Dispersive liquid–liquid microextraction (DLLME) is a modern sample pretreatment technique that is regarded as consilient with the current trends of modern analytical chemistry. DLLME is simple, inexpensive, environmentally friendly, and could offer high enrichment factors from a wide gap between acceptor and donor phases. As a consequence, DLLME has attracted considerable attention from researchers and, based on the numerous publications concerning DLLME, has been generally accepted in separation science since the technique's invention in 2006. However, several innate weaknesses of DLLME, which restrict the technique's use in certain fields, have led to various attempts or suggestions to improve this technique. The present review focuses on the recent advances made in DLLME; the selected papers that are discussed in this work represent modifications that fall into three main categories (exploration of new extraction solvents, disperser solvents and combination with other techniques). The recent applications of DLLME in environmental, food and biological samples are also summarised, covering almost all of the publications related to the technology from the beginning. In addition, the feasibility of future trends of DLLME is discussed.
Co-reporter:Hongyuan Yan, Suting Liu, Mengmeng Gao, Ning Sun
Journal of Chromatography A 2013 Volume 1294() pp:10-16
Publication Date(Web):14 June 2013
DOI:10.1016/j.chroma.2013.04.024
•Ionic liquid modified dummy imprinted microspheres (DMIMs) were synthesized.•DMIMs-SPE for rapid isolation of clenbuterol and clorprenaline in urine.•Matrix interferences were removed and analytes were concentrated.•Problem of template leakage on quantitative analysis was eliminated.New ionic liquid modified dummy molecularly imprinted microspheres (DMIMs) were synthesized by aqueous suspension polymerization using phenylephrine as dummy template and 1-allyl-3-ethylimidazolium bromide as co-functional monomer. The obtained DMIMs were characterized by Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM), and empolyed as the special sorbent of solid-phase extraction for isolation of clenbuterol (CLB) and clorprenaline (CLP) from urine sample. The results indicated that the ionic liquid modified polymers were monodispersed microspheres and had high selectivity and adsorbability to CLB and CLP, and the matrix interferences could be efficiently eliminated from the samples. Meanwhile, the effect of template leakage of DMIMs on quantitative analysis was avoided. Compared with other commercial sorbents (HLB, PCX, C18 and SCX), the DMIMs exhibited higher affinity and purification ability to CLP and CLB. Under the optimized conditions, good linearity was observed in a range of 0.90–400 μg L−1 (r2 = 0.9999) with LOD of 0.19 and 0.070 μg L−1 for CLP and CLB, respectively. The recoveries at three spiked levels were ranged from 93.3% to 106% with RSD ≤ 5.6% (n = 3).
Co-reporter:Hongyuan Yan, Xiaoling Cheng, and Ning Sun
Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 11) pp:2896-2901
Publication Date(Web):February 23, 2013
DOI:10.1021/jf400847b
Magnetic multi-core–shell molecularly imprinted microspheres (Fe3O4@MIMs) based on multi-Fe3O4 nanoparticles as core structures and dummy imprinted materials as shell structures have been synthesized by a surface-imprinted technique using dichlorodiphenyltrichloroethane as the dummy template and were successfully used as a specific adsorbent for rapid isolation of trace levels of dicofol from teas. The resulting Fe3O4@MIMs were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, and thermogravimetric analysis. In comparison to the imprinted polymers prepared by the traditional polymerizations, the obtained Fe3O4@MIMs showed regularly spherical shape, porous morphologies, high saturation magnetization [56.8 electromagnetic units (emu)/g], and rapid response time (15 s). The as-synthesized Fe3O4@MIMs, which incorporated the excellent molecular recognition and magnetic separation properties, were successfully used as special adsorbents for rapid isolation and extraction of trace levels of dicofol and its analogues from a complicated tea matrix.
Co-reporter:Suting Liu, Hongyuan Yan, Mingyu Wang, and Lihui Wang
Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 49) pp:11974-11980
Publication Date(Web):November 14, 2013
DOI:10.1021/jf403759t
New water-compatible molecularly imprinted microspheres were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization using 3-(2-carboxyethylsulfanylthiocarbonyl-sulfanyl) propionic acid as a hydrophilic chain-transfer agent, and employed as the sorbent of pipet tip molecularly imprinted solid-phase extraction (PT-MISPE) for rapid extraction and screening of ofloxacin, pefloxacin, norfloxacin, ciprofloxacin, and enrofloxacin in eggs. In comparison to conventional SPE methods, the presented PT-MISPE showed special selectivity, easy operation, and accessible device without expensive SPE apparatus. The presented PT-MISPE method combined advantages of dummy molecularly imprinted polymers and pipet tip solid-phase extraction. The presented method was linear over a calibration range of 25–2500 μg/kg with the limits of detections of 0.53–1.07 μg/kg. Good recoveries (89.1–102.5%) were achieved with relative standard deviations of 2.6–4.8%.
Co-reporter:Fang Wang, Hongyuan Yan, Ruijun Wu, Tianyu Cai, Kun Han and Zhao Li
Analytical Methods 2013 vol. 5(Issue 9) pp:2398-2405
Publication Date(Web):
DOI:10.1039/C3AY40145F
A highly selective dummy molecularly imprinted solid-phase extraction (DMISPE) method combined with liquid chromatography-ultraviolet detection was developed for the clean-up and screening of two triazine herbicides (cyanazine and atrazine) in tomato samples. The dummy molecularly imprinted polymers (DMIPs) were synthesized under thermal irradiation by bulk polymerization using cyromazine as a template molecule to avoid the effect of template leakage on quantitative analysis. Tomato juice samples could be directly loaded onto the DMIP cartridges and revealed the outstanding purifying effect. Under the optimum conditions of DMISPE–HPLC, good linearity for the two triazines were achieved in a range of 0.004–0.400 μg g−1 (r2 ≥ 0.9996) and their average recoveries at three spiked levels ranged from 97.8 to 108.5% with a relative standard deviation ≤4.9% (n = 3). The developed DMISPE–HPLC method eliminated the effect of template leakage while exhibiting the advantages of simplicity, selectivity and sensitivity, and could be potentially applied for the determination of triazine herbicides in complicated samples.
Co-reporter:Yehong Han, Hongyuan Yan, Xiaoling Cheng, Gengliang Yang and Baohui Li
Analytical Methods 2013 vol. 5(Issue 13) pp:3285-3290
Publication Date(Web):26 Apr 2013
DOI:10.1039/C3AY40170G
A simple, rapid and selective sample pretreatment method, molecularly imprinted matrix solid-phase dispersion (MI-MSPD) coupled with liquid chromatography, was developed for the rapid isolation of acyclovir (ACV) from edible creatural tissues. New molecularly imprinted polymer (MIP) synthesized by using theophylline as a dummy template revealed a high special affinity to ACV, and was employed as the selective dispersant of matrix solid-phase dispersion (MSPD) for the rapid screening of ACV. The presented method obviously reduced the tedious separation procedure, improved the extraction selectivity and purification efficiency, and significantly eliminated the effect of template leakage of MIP on quantitative analysis. The results indicated that the interference compounds originating from the creatural tissue matrix could be efficiently eliminated, and the elution was clean enough for HPLC analysis. Good linearity of ACV was obtained in a range of 0.10–50.0 μg g−1 with r2 = 0.9998, and the limit of quantification based on the signal to noise of 10 was 0.09 μg g−1. The recoveries at three spiked levels were in the range of 85.5–108.1% with RSD ≤ 3.7% (n = 3). The presented MI-MSPD method combined the advantages of MIP and MSPD, and could be applied for the rapid and selective screening of ACV in creatural tissues.
Co-reporter:Mengmeng Gao, Hongyuan Yan, Ning Sun
Analytica Chimica Acta 2013 800() pp: 43-49
Publication Date(Web):24 October 2013
DOI:10.1016/j.aca.2013.09.026
•Poly (hydroxyethyl methacrylate) polymers (PHEMA) were synthesized by RAFT polymerization.•A miniaturized syringe assisted extraction device was developed by 1.0 mL of syringe.•PHEMA-mini-SAE method was proposed for rapid screening of sulfadiazine and sulfamonomethoxine in milk.•The proposed method exhibited the advantages of simplicity, economy and easy controlled.A simple, convenient, and economic self-assembly miniaturized syringe assisted extraction (mini-SAE) using poly (hydroxyethyl methacrylate) polymer (PHEMA) as sorbent coupled with liquid chromatography was proposed for rapid screening of sulfadiazine (SD) and sulfamonomethoxine (SMM) in milk. The water-compatible PHEMA was synthesized by reversible addition-fragmentation chain transfer precipitation polymerization using trithiocarbonate as chain transfer agent and methanol–water system as reaction medium. The obtained PHEMA sorbent showed good affinity to sulfonamides and was successfully applied as a special sorbent for a mini-SAE device for simultaneous extraction and isolation of SD and SMM in milk samples. Under the optimum condition, good linearity was obtained in a range of 7.0–700 ng g−1 (r ≥ 0.9995) and the average recoveries of SD and SMM at three spiked levels were ranged from 85.6 to 100.3% with the relative standard deviations (RSD) ≤6.5%. The presented PHEMA-mini-SAE protocol could be potentially applied as an alternative tool for analyzing the residues of SAs in complicated biological samples.Water-compatible poly (hydroxyethyl methacrylate) polymer sorbent for miniaturized syringe assisted extraction of sulfonamides in milk.Download full-size image
Co-reporter:Hongyuan Yan, Jindong Qiao, Yuning Pei, Tao Long, Wen Ding, Kun Xie
Food Chemistry 2012 Volume 132(Issue 1) pp:649-654
Publication Date(Web):1 May 2012
DOI:10.1016/j.foodchem.2011.10.105
New molecularly imprinted microspheres synthesized by suspension polymerisation using phenylamine and naphthol as mimic template were successfully applied as selective sorbents for the solid-phase extraction used for the simultaneous determination of four Sudan dyes from preserved beancurd products. The obtained imprinted microspheres showed good recognition and selectivity to the four Sudan dyes in aqueous solution and the affinity could be easily controlled by adjusting the property of the solution. Under the selected experimental condition, the recoveries of the Sudan dyes in preserved beancurds at three spiked levels were ranged between 90.2–104.5% with the relative standard deviation of less than 6.8%. The limit of detection (LOD) and limit of quantification (LOQ) based on a signal-to-noise of 3 and 10 were in the range of 0.005–0.009 μg g−1 and 0.015–0.030 μg g−1, respectively. Comparing with alumina and C18-based extraction, the selectivity and repeatability of molecularly imprinted solid-phase extraction (MISPE) were obviously improved. This method could be potentially applied for the determination of Sudan dyes in complicated food samples.Highlights► New imprinted microspheres (MIM) were synthesized by aqueous suspension polymerisation. ► MIM used as SPE sorbent for extraction of four Sudan dyes in preserved beancurd. ► Mimic template technology overcome the drawbacks of template leakage in quantitative analysis. ► Comparing with alumina and C18-based extraction, the selectivity and repeatability of MISPE were improved. ► The recoveries of Sudan dyes were ranged in 90.2–104.5% with RSD of less than 6.8%.
Co-reporter:Hongyuan Yan, Fang Wang, Dandan Han and Gengliang Yang
Analyst 2012 vol. 137(Issue 12) pp:2884-2890
Publication Date(Web):13 Apr 2012
DOI:10.1039/C2AN35362H
A highly selective molecularly imprinted solid-phase extraction (MISPE) combined with liquid chromatography-ultraviolet detection was developed for the simultaneous isolation and determination of four plant hormones including indole-3-acetic acid (IAA), indole-3-propionic acid (IPA), indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA) in banana samples. The new molecularly imprinted microspheres (MIMs) prepared by aqueous suspension polymerization using 3-hydroxy-2-naphthoic acid and 1-methylpiperazine as mimic templates performed with high selectivity and affinity for the four plant hormones, and applied as selective sorbents of solid-phase extraction could effectively eliminate the interferences of the banana matrix. Good linearity was obtained in a range of 0.04–4.00 μg g−1 and the recoveries of the four plant hormones at three spiked levels ranged from 78.5 to 107.7% with the relative standard deviations (RSD) of less than 4.6%. The developed MISPE-HPLC protocol obviously improved the selectivity and eliminated the effect of template leakage on quantitative analysis, and could be applied for the determination of plant hormones in complicated biological samples.
Co-reporter:Hongyuan Yan, Fang Wang, Hui Wang, Gengliang Yang
Journal of Chromatography A 2012 Volume 1256() pp:1-8
Publication Date(Web):21 September 2012
DOI:10.1016/j.chroma.2012.07.037
A simple, convenient and high selective miniaturized molecularly imprinted matrix solid-phase dispersion (mini-MI-MSPD) technique using l-tryptophan-imprinted polymers as sorbents was proposed for simultaneous extraction of four auxins (indole-3-acetic acid (IAA), indole-3-propionic acid (IPA), indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA)) from orange samples coupled with high performance liquid chromatography–ultraviolet detection. The molecularly imprinted polymers (MIPs) synthesized using l-tryptophan as dummy template showed high affinity and selectivity to auxins, and so they were applied as the specific dispersant of MSPD to simultaneously eliminate the effect of template leakage on quantitative analysis. Under the optimized conditions, good linearity was obtained in a range of 0.02–2.00 μg g−1 and the average recoveries of four auxins at three spiked levels ranged from 87.6% to 104.5% with the relative standard deviation (RSD) ≤4.4%. The presented mini-MI-MSPD method combined the advantages of MSPD for allowing the extraction, dispersion and homogenization in a single step and the advantages of MIPs for high affinity and selectivity towards four auxins, which could be applied to the determination of auxins in complicated vegetal samples.Highlights► A simple and rapid mini-MI-MSPD method for isolation of auxins in orange. ► MIP synthesized by tryptophan as dummy template show high affinity to auxins. ► Rapid screening of four auxins from orange samples with improved purification effect. ► Extraction efficiency was markedly increased with reduced equilibrium time. ► The mini-MI-MSPD–HPLC method improved the selectivity and eliminated the effect of template leakage on quantitative analysis.
Co-reporter:Hongyuan Yan, Xiaoling Cheng and Kuo Yan
Analyst 2012 vol. 137(Issue 20) pp:4860-4866
Publication Date(Web):10 Aug 2012
DOI:10.1039/C2AN36046B
A rapid ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) method coupled with gas chromatography-flame ionization detection (GC-FID) is proposed for the rapid screening of five phthalate esters in bottled beverages. In the UASEME procedure, a nonionic surfactant (Triton X-100) was used as the emulsifier, without application of any organic dispersive solvents typically required in dispersive liquid–liquid microextraction. Triton X-100 as the emulsifier accelerated the formation of fine droplets from the extraction solvent in the sample solution under ultrasound radiation, thus combining the advantages of dispersive liquid–liquid microextraction (DLLME) and ultrasound-assisted emulsification microextraction (UAEME). Under the optimum conditions, the enrichment factors of the five analytes ranged from 230 to 288 fold and the recoveries ranged from 89.3% to 100.1%. The limits of detection (LODs) based on signal to noise of 3 were 0.41–0.79 μg L−1. Intra-assay and inter-assay precision, expressed as the relative standard deviation (RSD), were ≤5.46% and 5.81%, respectively. The proposed UASEME-GC/FID method was demonstrated to be simple, practical and environmentally friendly for the determination of trace phthalate esters in beverage samples.
Co-reporter:Hui Wang;Jindong Qiao
Journal of Separation Science 2012 Volume 35( Issue 2) pp:292-298
Publication Date(Web):
DOI:10.1002/jssc.201100753
Abstract
A simple and miniaturized pretreatment procedure combining matrix solid-phase dispersion (MSPD) with ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) technique was proposed in first time for simultaneous determination of three pyrethroids (fenpropathrin, cyhalothrin and fenvalerate) in soils. The solid samples were directly extracted using MSPD procedure, and the eluent of MSPD was used as the dispersive solvent of the followed DLLME procedure for further purification and enrichment of the analytes before GC-ECD analysis. Good linear relationships were obtained for all the analytes in a range of 5.0–500.0 ng/g with LOQs (S/N=10) ranged from 1.51 to 3.77 ng/g. Average recoveries at three spiked levels were in a range of 83.6–98.5% with RSD≤7.3%. The present method combined the advantages of MSPD and DLLME, and was successfully applied for the determination of three pyrethroids in soil samples.
Co-reporter:Hongyuan Yan, Mengmeng Gao, and Jindong Qiao
Journal of Agricultural and Food Chemistry 2012 Volume 60(Issue 27) pp:6907-6912
Publication Date(Web):June 15, 2012
DOI:10.1021/jf301224t
The new ionic liquid modified polymeric microspheres (ILPM) were synthesized by precipitation polymerization using 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) as the functional monomer, divinylbenzene (DVB) as the cross-linker, and a mixture of toluene and acetonitrile as the dispersant solvent. The obtained ILPM showed good adsorbability to the four kinds of Sudan dyes and were successfully applied as a special sorbent of solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC) for the simultaneous isolation and determination of four Sudan dyes from foodstuff samples. Compared with the traditional SPE adsorbents such as neutral alumina and C18, the ILPM sorbents provided higher recovery with a significant purification effect. Good linearity was obtained in a range of 0.05–4.0 μg/g (r2 ≥ 0.9996) for the four kinds of Sudan dyes, and the average recoveries at three spiked levels ranged from 92.5% to 106.1% with the relative standard deviations ≤5.7%. The proposed ILPM-SPE-HPLC method could be potentially applied to rapid isolation and determination of Sudan dyes in complicated food samples.
Co-reporter:Hongyuan Yan, Xiaoling Cheng, and Gengliang Yang
Journal of Agricultural and Food Chemistry 2012 Volume 60(Issue 22) pp:5524-5531
Publication Date(Web):May 11, 2012
DOI:10.1021/jf300660m
In this paper, a highly selective sample cleanup procedure combing dummy molecular imprinting and solid-phase extraction (DMI-SPE) was developed for the simultaneous isolation and determination of five phthalate esters in plastic bottled beverages. The new imprinted microspheres were synthesized via precipitation polymerization using diisononyl phthalate as a dummy template that showed high selectivity and affinity to the five kinds of phthalate esters and were successfully applied as selective sorbents of DMI-SPE for the simultaneous determination of the phthalate esters from plastic bottled beverages. Good linearity was obtained in a range of 5.0–750.0 μg/L, and the average recoveries of the five phthalate esters at three spiked levels ranged from 84.3 to 96.2% with the relative standard deviations less than 5.49%. The developed extraction protocol eliminated the effect of template leakage on quantitative analysis and could be applied for the determination of phthalate esters in complicated functional beverages products.
Co-reporter:Hongyuan Yan, Yehong Han and Jingjing Du
Analytical Methods 2012 vol. 4(Issue 9) pp:3002-3006
Publication Date(Web):29 Jun 2012
DOI:10.1039/C2AY25271F
A new solid-phase extraction and dispersive liquid–liquid microextraction (SPE-DLLME) method coupled with gas chromatography electron capture detection (GC-ECD)was established for the detection of cypermethrin and permethrin in river water. The samples were firstly extracted using a large-volume SPE procedure and the eluents of SPE were further purified and enriched by the following DLLME. Good linearity was observed in the range of 0.015–3.87 μg L−1 for cypermethrin and 0.065–16.2 μg L−1 for permethrin with the correlation coefficient (r) ≥ 0.9995. The limits of detection based on S/N = 3 were 0.48 and 3.81 ng L−1 for cypermethrin and permethrin, respectively. Under optimized conditions, the enrichment factors for cypermethrin and permethrin were 1545- and 2138-fold, respectively. The developed method was successfully used to detect the two pyrethroid residues in river water samples.
Co-reporter:Hongyuan Yan, Hui Wang, Jindong Qiao, Gengliang Yang
Journal of Chromatography A 2011 Volume 1218(Issue 16) pp:2182-2188
Publication Date(Web):22 April 2011
DOI:10.1016/j.chroma.2011.02.042
A new kind of aniline–naphthol molecularly imprinted microsphere (MIM) synthesized by aqueous suspension polymerization was applied as a selective sorbent of miniaturized matrix solid-phase dispersion combining with dispersive liquid–liquid microextraction (MSPD–DLLME) for the simultaneous determination of four Sudans in egg yolk samples. The solid sample was directly blended with MIM in MSPD procedure and the eluent of MSPD was used as the dispersive solvent of the followed DLLME for further purification and enrichment of the analytes before HPLC analysis. Good linearity for all the Sudan dyes was ranged from 0.02 μg g−1 to 2.0 μg g−1 (r2 ≥ 0.9990) and their recoveries at three spiked levels were ranged from 87.2% to 103.5% with RSD less than 6.1% (n = 3). The presented MIM–MSPD–DLLME method combined the advantages of MIM, MSPD and DLLME, and could be applied for the determination of Sudans in complicated food samples.
Co-reporter:Hongyuan Yan, Jindong Qiao, Hui Wang, Gengliang Yang and Kyung Ho Row
Analyst 2011 vol. 136(Issue 12) pp:2629-2634
Publication Date(Web):10 May 2011
DOI:10.1039/C0AN00951B
A simple and highly selective molecularly imprinted solid-phase extraction (MISPE) combined with ultrasound-assisted dispersive liquid–liquid microextraction (DLLME) was developed for the determination of four Sudan dye (I, II, III, and IV) residues in sausage products. The novel molecularly imprinted microspheres (MIMs) synthesized by aqueous suspension polymerization using phenylamine–naphthol as the dummy template show high affinity to the four Sudan dyes and were applied as selective sorbents of MISPE–DLLME to overcome the drawbacks of template leakage in quantitative analysis. Good linearity was obtained in a range of 0.005–2.0 μg g−1 and the average recoveries of the four Sudan dyes at three spiked levels ranged from 86.3 to 107.5%. The MISPE–DLLME–HPLC protocol significantly improved the purification and enrichment of the analytes and eliminated the template leakage of the conventional MISPE on quantitative analysis.
Co-reporter:Jindong Qiao;Hui Wang ;Yunkai Lv
Journal of Separation Science 2011 Volume 34( Issue 19) pp:2668-2673
Publication Date(Web):
DOI:10.1002/jssc.201100209
Abstract
A new molecularly imprinted solid-phase extraction (MISPE) procedure combined with liquid chromatography was developed for the simultaneous selective extraction and determination of ofloxacin (OFL) and lomefloxacin (LOM) in chicken muscle samples. The water-compatible molecularly imprinted microspheres (MIMs) were synthesized by aqueous suspension polymerization using 2-hydroxy-3-naphthoic acid and 1-methylpiperazine as mimic templates. The MIMs applied as selective sorbents in SPE method showed high selectivity and affinity to OFL and LOM in complex biological matrices. Good linearity was obtained in a range of 0.025–2.0 μg/g, and the average recoveries of OFL and LOM at three spiked levels ranged from 94.4 to 96.9%, respectively, with the relative standard deviation ≤4.7%. The developed MISPE-HPLC method was successfully applied to the isolation of OFL and LOM in chicken muscles, which demonstrated the potential ability of the novel MIMs for selective extraction of fluoroquinolones in biological samples.
Co-reporter:Hui Wang, Hongyuan Yan, Mande Qiu, Jindong Qiao, Gengliang Yang
Talanta 2011 Volume 85(Issue 4) pp:2100-2105
Publication Date(Web):30 September 2011
DOI:10.1016/j.talanta.2011.07.061
The novel molecularly imprinted microsphere (MIM) that could be applied as special sorbent was synthesized by aqueous suspension polymerization using 1,1-bis(4-chlorophenyl)-1,2,2,2-tetrachloroethane (α-chloro-DDT) as the dummy template. The obtained MIM exhibited good recognition and selectivity to dicofol and it was successfully applied as selective sorbent of solid-phase extraction for the determination of dicofol from aquatic products. At the optimum conditions of the molecularly imprinted solid-phase extraction (MISPE) coupled with GC-ECD, good linearity for dicofol was achieved in a range of 0.4–100 ng g−1 (r2 = 0.9995) and the recoveries at three spiked levels were ranged from 85.8% to 101.2% for aquatic products with the relative standard deviation (RSD) less than 5.6%. The presented MISPE-GC-ECD method exhibited the advantages of simplicity, selectivity and sensitivity, and could be potentially applied to the determination of dicofol in complicated aquatic products.
Co-reporter:Hongyuan Yan, Hui Wang, Xinying Qin, Baomi Liu, Jingjing Du
Journal of Pharmaceutical and Biomedical Analysis 2011 54(1) pp: 53-57
Publication Date(Web):
DOI:10.1016/j.jpba.2010.08.007
Co-reporter:Jindong Qiao;Hui Wang;Yupei Wu;Pengyu Pan;Yuru Geng
Chromatographia 2011 Volume 73( Issue 3-4) pp:227-233
Publication Date(Web):2011 February
DOI:10.1007/s10337-010-1872-7
A highly selective molecularly imprinted solid-phase extraction (MISPE) combined with liquid chromatography-ultraviolet detection was developed for the simultaneous isolation and determination of four Sudan dyes (I, II, III and IV) in egg-yolk products. The imprinted microspheres synthesized by suspension polymerization using phenylamine–naphthol as mimic template show high selectivity and affinity to the four kinds of Sudan dyes and were successfully applied as selective sorbents of solid-phase extraction for the simultaneous determination of the four Sudans from egg-yolk samples. Good linearity was obtained in a range of 0.062–10 μg g−1 and the average recoveries of the four Sudans at three spiked levels ranged from 94.1 to 102.5% with the relative standard deviations less than 5.8%. The developed extraction protocol eliminated the effect of template leakage on quantitative analysis and could be applied for the determination of Sudans in complicated food samples.
Co-reporter:Hongyuan Yan, Xiaoling Cheng, Baomi Liu
Journal of Chromatography B 2011 Volume 879(Issue 25) pp:2507-2512
Publication Date(Web):1 September 2011
DOI:10.1016/j.jchromb.2011.07.001
A new method was developed for the simultaneous determination of six phthalate esters in bottled milks using ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) followed by gas chromatography–flame ionization detection (GC–FID). 0.8 mL of methanol (dispersant) and 40 μL of CCl4 (extractant) were injected into 8.0 mL of milk solution and then emulsified the mixture by ultrasound for 2.0 min to form the cloudy solution. Under the optimum condition, the enrichment factors of the analytes ranged from 220 to 270 fold and the recovery ranged from 93.2% to 105.7%. Good linearity was observed for all analytes in a range of 0.8–51 ng g−1 with the correlation coefficient (r2) ≥0.9992. The limits of detection (LODs) based on signal to noise of 3 were 0.64–0.79 ng g−1. The repeatability evaluated as intra-day and inter-day precision (relative standard deviation, RSD) were less than 4.0% (n = 5). The presented UA-DLLME–GC–FID method was successfully applied to determine the six phthalate esters in different bottled milk products.
Co-reporter:Hongyuan Yan, Baomi Liu, Jingjing Du, Gengliang Yang, Kyung Ho Row
Journal of Chromatography A 2010 Volume 1217(Issue 32) pp:5152-5157
Publication Date(Web):6 August 2010
DOI:10.1016/j.chroma.2010.06.008
A simple ultrasound-assisted dispersive liquid–liquid microextraction method combined with liquid chromatography was developed for the preconcentration and determination of six pyrethroids in river water samples. The procedure was based on a ternary solvent system to formatting tiny droplets of extractant in sample solution by dissolving appropriate amounts of water-immiscible extractant (tetrachloromethane) in watermiscible dispersive solvent (acetone). Various parameters that affected the extraction efficiency (such as type and volume of extraction and dispersive solvent, extraction time, ultrasonic time, and centrifuging time) were evaluated. Under the optimum condition, good linearity was obtained in a range of 0.00059–1.52 mg L−1 for all analytes with the correlation coefficient (r2) > 0.999. Intra-assay and inter-assay precision evaluated as the relative standard deviation (RSD) were less than 3.4 and 8.9%. The recoveries of six pyrethroids at three spiked levels were in the range of 86.2–109.3% with RSD of less than 8.7%. The enrichment factors for the six pyrethroids were ranged from 767 to 1033 folds.
Co-reporter:Hongyuan Yan, Baomi Liu, Jingjing Du and Kyung Ho Row
Analyst 2010 vol. 135(Issue 10) pp:2585-2590
Publication Date(Web):10 Aug 2010
DOI:10.1039/C0AN00441C
A simple and rapid sample pretreatment procedure based on ultrasound-assisted dispersive liquid–liquid microextraction is proposed for the determination of four phthalate esters (dibutyl phthalate, butyl benzyl phthalate, diisooctyl phthalate, dioctyl phthalate) in bottled water samples using gas chromatography-flame ionization detection. An ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution using less disperser solvent, which markedly increased the extraction efficiency and reduced the equilibrium time. Under optimum conditions, the enrichment factor of the four analytes ranged from 490- to 530-fold and the recovery ranged from 84.8%∼104.7%. A good linear relationship between the peak area and the concentration of analytes was obtained in the range of 6.9∼444 μg L−1. Intra-assay and inter-assay precision expressed as relative standard deviation (RSD) were in the range of 1.4∼2.0% and 3.0∼3.7%, respectively. This method offers a good alternative for routine analysis due to its simplicity and reliability.
Co-reporter:Hongyuan Yan;Jingjing Du;Xiguo Zhang;Gengliang Yang;Kyung Ho Row;Yunkai Lv
Journal of Separation Science 2010 Volume 33( Issue 12) pp:1829-1835
Publication Date(Web):
DOI:10.1002/jssc.200900716
Abstract
A simple and rapid ultrasound-assisted dispersive liquid–liquid microextraction method coupled with GC-flame ionization detection was developed for simultaneous determination of nine pyrethroids in domestic wastewater samples. An ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution using small volume of disperser solvent, which markedly increased the extraction efficiency and reduced the equilibrium time. Various parameters affecting the extraction efficiency were investigated, including the type and volume of extraction solvent and disperser solvent, extraction and ultrasonic time. Good linearity was obtained for all analytes in the range of 0.8–100 μg/L with the correlation coefficient (r2)≥0.998. The recoveries at three spiking levels ranged from 75.3 to 101.2% with the RSD less than 8.7% (n=5). Under the optimum condition, the enrichment factors for the nine pyrethroids ranged from 728- to 1725-fold. This method offered a good alternative for routine analysis due to its simplicity and reliability.
Co-reporter:Jingjing Du, Hongyuan Yan, Dandan She, Baomi Liu, Gengliang Yang
Talanta 2010 Volume 82(Issue 2) pp:698-703
Publication Date(Web):15 July 2010
DOI:10.1016/j.talanta.2010.05.035
A new method was developed for simultaneous determination of cypermethrin and permethrin residues in pear juice with ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) and gas chromatography-flame ionization detection (GC-FID). 3.5 mL of methanol (dispersant) and 30 μL of C2Cl4 (extractant) were injected into 5.0 mL of pear juice sample and then emulsified by ultrasound for 2.0 min to forming the cloudy solution. Under the optimum condition, the enrichment factors for cypermethrin and permethrin were 344 and 351 fold respectively. Good linearity was observed in a range of 0.009-1.52 μg g−1 with the correlation coefficient (r2)≥0.9993. The limits of detection (LODs) were 3.1 and 2.2 μg kg−1 for cypermethrin and permethrin, respectively (S/N = 3). The recoveries of the method evaluated at three spiked levels were in the range of 92.1%-107.1%. The repeatability evaluated as intra-day and inter-day precision (RSDs) were less than 4.0% (n = 5). The developed method was successfully applied to determine the two pesticide residues in different pear juice samples.
Co-reporter:Najing Fu, Runqiu Lv, Zhixin Guo, Yiwei Guo, Xiaoyu You, Baokun Tang, Dandan Han, Hongyuan Yan, Kyung Ho Row
Journal of Chromatography A (7 April 2017) Volume 1492() pp:
Publication Date(Web):7 April 2017
DOI:10.1016/j.chroma.2017.02.036
•A satisfactory sample pretreatment based on non-polluting solvent.•Application of choline chloride deep eutectic solvents and their modified materials.•Solid phase extraction based on deep eutectic solvents.•Deep eutectic solvents have great potential for the green pretreatment of samples.In this work, choline chloride (ChCl) deep eutectic solvents (DESs) were evaluated for the pretreatment of palm samples in the analysis of polyphenols, such as protocatechuic acid, catechins, epicatechin, and caffeic acid. During the enrichment step of the pretreatment, eight DESs comprising ChCl with ethylene glycol (EG), glycerol (Gly), xylitol (Xyl), phenol (Ph), formic acid (FA), citric acid (CiA), oxalic acid (OA), or malonic acid (MA), were prepared and applied to the reflux extraction of polyphenols from palm samples. All the DESs exhibited higher polyphenol extraction efficiency than methanol, and the highest extraction efficiency was obtained using ChCl-FA (1:1, mole ratio). For the purification step of the pretreatment, eight ChCl DES-modified adsorbents were prepared by hydrothermal polymerization and packed into solid-phase extraction (SPE) cartridges, and ChCl-Urea, ChCl-Gly, ChCl-FA, and water, were used as eluents. The ChCl DES-modified adsorbents were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, and Brunauer–Emmett–Teller surface analysis, and the polyphenols were analyzed by mass spectrometry and high-performance liquid chromatograph-ultraviolet detection. The highest purification efficiency was obtained using the ChCl-Ph DES-modified adsorbent as the SPE packing material and ChCl-Urea-H2O (1:1:5, mole ratio), ChCl-Gly (1:1, mole ratio), ChCl-FA-H2O (1:1:5, mole ratio), and H2O as the eluents. Compared to conventional purification processes that employ commercial C18 or C8 SPE columns with organic solvents as eluents, the ChCl DES-based SPE purification process successfully avoided the use of expensive commercial SPE columns and organic solvents. Furthermore, it isolated a larger amount of the target compounds under the same experimental conditions, and could be applied over five cycles with good reversibility. This work indicates that DESs as green solvents have great potential for the totally green pretreatment of samples during the enrichment and purification processes.
Co-reporter:Shiru Liang, Hongyuan Yan, Jiankun Cao, Yehong Han, Shigang Shen, Ligai Bai
Analytica Chimica Acta (25 January 2017) Volume 951() pp:
Publication Date(Web):25 January 2017
DOI:10.1016/j.aca.2016.11.009
•Molecularly imprinted phloroglucinol-formaldehyde-melamine resin was synthesized.•Deep Eutectic Solvent was used in the preparation of molecularly imprinted polymers.•The prepared materials presented specific recognition to CLP and BAM in urine.•Dummy template eliminated the influence of template leakage on quantitative analysis.A new molecularly imprinted phloroglucinol–formaldehyde–melamine resin (MIPFMR) was synthesized in a deep eutectic solvent (DES) using phenylephrine as a dummy template. The MIPFMR was used as a solid phase extraction (SPE) sorbent for the selective isolation and recognition of clorprenaline (CLP) and bambuterol (BAM) in urine. Phloroglucinol and melamine were used as double functional monomers that introduced abundant hydrophilic groups (such as hydroxyl groups, imino groups, and ether linkages) into the MIPFMR, making it compatible with aqueous solvents. In addition, the formation of DES by combining the quaternary ammonium salt of choline chloride with ethylene glycol as a hydrogen bond donor was an environmentally safe alternative to toxic organic solvents such as chloroform and dimethylsulfoxide that are typically used in the preparation of most molecularly imprinted polymers (MIPs). Moreover, MIPFMR-based SPE of CLP and BAM in urine resulted in higher recoveries and purer extracts than those obtained by using other SPE materials (e.g., SCX, C18, HLB, and non-imprinted phloroglucinol–formaldehyde–melamine resin (NIPFMR)). The optimized MIPFMR–SPE–HPLC–UV method had good linearity (r2 ≥ 0.9996) ranging from 15.0 to 3000.0 ng mL−1 for CLP and BAM, and the recoveries at three spiked levels ranged from 91.7% to 100.1% with RSDs ≤7.6%. The novel MIPFMR–SPE–HPLC–UV method is simple, selective, and accurate, and can be used for the determination of CLP and BAM in urine samples.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 9) pp:
Publication Date(Web):
DOI:10.1039/C3AY40145F
A highly selective dummy molecularly imprinted solid-phase extraction (DMISPE) method combined with liquid chromatography-ultraviolet detection was developed for the clean-up and screening of two triazine herbicides (cyanazine and atrazine) in tomato samples. The dummy molecularly imprinted polymers (DMIPs) were synthesized under thermal irradiation by bulk polymerization using cyromazine as a template molecule to avoid the effect of template leakage on quantitative analysis. Tomato juice samples could be directly loaded onto the DMIP cartridges and revealed the outstanding purifying effect. Under the optimum conditions of DMISPE–HPLC, good linearity for the two triazines were achieved in a range of 0.004–0.400 μg g−1 (r2 ≥ 0.9996) and their average recoveries at three spiked levels ranged from 97.8 to 108.5% with a relative standard deviation ≤4.9% (n = 3). The developed DMISPE–HPLC method eliminated the effect of template leakage while exhibiting the advantages of simplicity, selectivity and sensitivity, and could be potentially applied for the determination of triazine herbicides in complicated samples.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 13) pp:NaN3290-3290
Publication Date(Web):2013/04/26
DOI:10.1039/C3AY40170G
A simple, rapid and selective sample pretreatment method, molecularly imprinted matrix solid-phase dispersion (MI-MSPD) coupled with liquid chromatography, was developed for the rapid isolation of acyclovir (ACV) from edible creatural tissues. New molecularly imprinted polymer (MIP) synthesized by using theophylline as a dummy template revealed a high special affinity to ACV, and was employed as the selective dispersant of matrix solid-phase dispersion (MSPD) for the rapid screening of ACV. The presented method obviously reduced the tedious separation procedure, improved the extraction selectivity and purification efficiency, and significantly eliminated the effect of template leakage of MIP on quantitative analysis. The results indicated that the interference compounds originating from the creatural tissue matrix could be efficiently eliminated, and the elution was clean enough for HPLC analysis. Good linearity of ACV was obtained in a range of 0.10–50.0 μg g−1 with r2 = 0.9998, and the limit of quantification based on the signal to noise of 10 was 0.09 μg g−1. The recoveries at three spiked levels were in the range of 85.5–108.1% with RSD ≤ 3.7% (n = 3). The presented MI-MSPD method combined the advantages of MIP and MSPD, and could be applied for the rapid and selective screening of ACV in creatural tissues.
Co-reporter:Hongyuan Yan, Yehong Han and Jingjing Du
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 9) pp:NaN3006-3006
Publication Date(Web):2012/06/29
DOI:10.1039/C2AY25271F
A new solid-phase extraction and dispersive liquid–liquid microextraction (SPE-DLLME) method coupled with gas chromatography electron capture detection (GC-ECD)was established for the detection of cypermethrin and permethrin in river water. The samples were firstly extracted using a large-volume SPE procedure and the eluents of SPE were further purified and enriched by the following DLLME. Good linearity was observed in the range of 0.015–3.87 μg L−1 for cypermethrin and 0.065–16.2 μg L−1 for permethrin with the correlation coefficient (r) ≥ 0.9995. The limits of detection based on S/N = 3 were 0.48 and 3.81 ng L−1 for cypermethrin and permethrin, respectively. Under optimized conditions, the enrichment factors for cypermethrin and permethrin were 1545- and 2138-fold, respectively. The developed method was successfully used to detect the two pyrethroid residues in river water samples.
![7H-Pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylicacid, 9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-, (3R)-](http://img.cochemist.com/ccimg/101000/100986-86-5.png)
![7H-Pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylicacid, 9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-, (3R)-](http://img.cochemist.com/ccimg/101000/100986-86-5_b.png)
![Benzenemethanol, 4-amino-3,5-dichloro-α-[[(1,1-dimethylethyl)amino]methyl]-](/data/chemimg/568900/37148-27-9.png)
![Benzenemethanol, 4-amino-3,5-dichloro-α-[[(1,1-dimethylethyl)amino]methyl]-](/data/chemimg/568900/37148-27-9_b.png)
![2-Propenoic acid, 1,1'-[2-[[3-[(1-oxo-2-propen-1-yl)oxy]-2,2-bis[[(1-oxo-2-propen-1-yl)oxy]methyl]propoxy]methyl]-2-[[(1-oxo-2-propen-1-yl)oxy]methyl]-](/data/chemimg/459700/29570-58-9.png)
![2-Propenoic acid, 1,1'-[2-[[3-[(1-oxo-2-propen-1-yl)oxy]-2,2-bis[[(1-oxo-2-propen-1-yl)oxy]methyl]propoxy]methyl]-2-[[(1-oxo-2-propen-1-yl)oxy]methyl]-](/data/chemimg/459700/29570-58-9_b.png)
