-
[show abstract]
[hide abstract]
ABSTRACT: 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 0.90-400μgL(-1) (r(2)=0.9999) with LOD of 0.19 and 0.070μgL(-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).
Journal of chromatography. A 04/2013; · 4.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Magnetic multi-core-shell molecularly imprinted microspheres (Fe3O4@MIMs) based on multi-Fe3O4 nanoparticles as core and dummy imprinted materials as shell structure have been synthesized by surface imprinted technique using dichlorodiphenyltrichloroethane as 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, respectively. Compared to the imprinted polymers that prepared by the traditional polymerizations, the obtained Fe3O4@MIMs showed regularly spherical shape, porous morphologies, high saturation magnetization (56.8 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 adsorbent for rapid isolation and extraction of trace levels of dicofol and its analogues from complicated tea matrix.
Journal of Agricultural and Food Chemistry 02/2013; · 2.82 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A simple, convenient and high selective molecularly imprinted matrix solid-phase dispersion (MI-MSPD) using water-compatible cyromazine-imprinted polymer as adsorbent was proposed for the rapid screening of melamine from bovine milk coupled with liquid chromatography-ultraviolet detection. The molecularly imprinted polymers (MIPs) synthesized by cyromazine as dummy template and reformative methanol-water system as reaction medium showed higher affinity and selectivity to melamine, and so they were applied as the specific dispersant of MSPD to extraction of melamine and simultaneously eliminate the effect of template leakage on quantitative analysis. Under the optimized conditions, good linearity was obtained in a range of 0.24-60.0μgg(-1) with the correlation coefficient of 0.9994. The recoveries of melamine at three spiked levels were ranged from 86.0 to 96.2% with the relative standard deviation (RSD)≤4.0%. This proposed MI-MSPD method combined the advantages of MSPD and MIPs, and could be used as an alternative tool for analyzing the residues of melamine in complex milk samples.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 09/2012; · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
The Analyst 08/2012; 137(20):4860-6. · 4.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Journal of chromatography. A 07/2012; 1256:1-8. · 4.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The new ionic liquid modified polymeric microspheres (ILPM) were synthesized by precipitation polymerization using 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF(6)]) 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 C(18), 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 (r(2) ≥ 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.
Journal of Agricultural and Food Chemistry 06/2012; · 2.82 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Journal of Agricultural and Food Chemistry 05/2012; 60(22):5524-31. · 2.82 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
The Analyst 05/2012; 137(12):2884-90. · 4.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A simple on-line molecularly imprinted solid-phase extraction coupled with liquid chromatographic separation was developed
for the simultaneous determination of enrofloxacin and its active metabolite ciprofloxacin from urine samples. The molecularly
imprinted monolithic columns were synthesized in water-containing systems using norflorxacin as dummy template and methanol–water
(5:1, v/v) as porogenic solvent, which reveal high affinity to enrofloxacin and ciprofloxacin in the aqueous environment. Due to the
unique porous structure and flow-through channels existing in the network skeleton of the imprinted monolith, urine samples
could be injected directly into the imprinted column, proteins and other biological matrix were quickly washed out and the
analytes were selectively retained and enriched. Good linearity was obtained from 0.05 to 200mgL−1 with relative standard deviations less than 3.1%. The recoveries were higher than 87% at three different concentrations and
the limit of detection of the method was 0.01mgL−1. Moreover, by increasing the injection volume, the sensitivity of the method could be further improved.
Chromatographia 04/2012; 70(7):1087-1093. · 1.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study developed a simple and sensitive liquid chromatography method to quantify the multiple active alkaloids (matrine,
sophocarpine, and sophoridine) from sophora flavescens ait in urine samples simultaneously. The results showed that liquid-liquid extraction using water as the solvent could effectively
isolate all the analyses with the lowest matrix effects. A low concentration of diethylamine (0.07%, v/v) in the mobile phase
improved dramatically the resolution of all the alkaloids with less interference from the matrix. Good linearity ranging from
0.025 to 1250.0 µg/mL for all analytes was obtained, and the accuracy and precision varied from 73.25 to 87.86% and 1.4 to
2.2%, respectively. Finally, the suitability of the proposed method was demonstrated in the urinary drug excretion of 4 volunteers
receiving an oral dose of a sophora flavescens ait extract. The intra and inter RSD were ≤ 1.9%.
Biotechnology and Bioprocess Engineering 04/2012; 14(5):675-679. · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Porous polymer monolithic columns have been prepared by the direct free radical copolymerization of methacrylic acid and ethylene
glycol dimethacrylate within the confines of a chromatographic column in the presence of toluene-dodecanol as a porogenic
solvent. Recognition mechanism and effects of the chromatographic condition such as mobile phase composition, flow rate and
temperature on the retention and separation were discussed. The results showed hydrogen-bonding interaction and hydrophobic
interaction play an important role in retention and separation in this kind of monolithic column. Compared with traditional
particle columns, the monolithic columns showed attractive significant interest because of their ease of preparation, high
separation efficiency, low backpressure and fast analysis.
Korean Journal of Chemical Engineering 04/2012; 23(4):625-630. · 0.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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 0.062–10μgg−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.
KeywordsColumn liquid chromatography–Molecularly imprinted solid-phase extraction–Imprinted microspheres–Sudan dyes–Egg yolk
Chromatographia 04/2012; 73(3):227-233. · 1.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Monolithic molecularly imprinted columns were designed and prepared by anin-situ thermal-initiated copolymerization technique for rapid separation of tryptophan andN-CBZ-phenylalanine enantiomers. The influence of polymerization conditions and separation conditions on the specific molecular
recognition ability for enantiomers and diastereomers was investigated. The specious molecular recognition was found to be
dependent on the stereo structures and the arrangement of functional groups of the imprinted molecule and the cavities in
the molecularly imprinted polymer (MIP). Moreover, hydrogen bonding interactions and hydrophobic interactions played an important
role in the retention and separation. Compared to conventional MIP preparation procedures, the present method is very simple,
and its macroporous structure has excellent separation properties.
Biotechnology and Bioprocess Engineering 04/2012; 11(4):357-363. · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A simple and precise method for chiral separation of tryptophan enantiomers using high performance liquid chromatography with
aligand exchange mobile phase was developed. Chiral separation was performed on a conventional C18 column, using a mobile phase that consisted of a water-methanol solution (88∶12, v/v) containing 10 mmol/Ll-leucine and 5 mmol/L copper sulfate as a chiral ligand additive at a flow rate of 1.0 mL/min. This method allowed baseline
separation of two enantiomers with a resolution of 1.84 in less than 30 min. The effect of various conditions, including concentration,
type of ligand, organic modifier, pH, flow rate, and temperature, on enantioseparation were evaluated and chiral recognition
mechanisms were investigated. Thermodynamic data (ΔΔH and ΔΔS) obtained by van't Hoff plots revealed that enantioseparation is an enthalpy-controlled process.
Biotechnology and Bioprocess Engineering 04/2012; 12(3):235-241. · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The combination of molecularly imprinted polymers (MIPs) and solid phase extraction (SPE) is reviewed. MIPs, which have high selectivity and affinity for a predetermined molecule (template), have been used as sorbents for SPE to selectively isolate analytes from biological, pharmaceutical, and environmental samples. Solid phase extraction with molecularly imprinted polymers (MIP–SPE) is a promising technique which allows specific analytes to be selectively extracted from complex matrices. This survey summarizes the characteristics, development and application of MIP–SPE in recent years. Existed problems and the future direction of MIP–SPE are also discussed.
Chromatographia 04/2012; 64(11):625-634. · 1.20 Impact Factor
-
[show abstract]
[hide abstract]
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.
Journal of Separation Science 12/2011; · 2.73 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new molecularly imprinted polymer was synthesized using ofloxacin and theophylline as template and methacryclic acid as function monomer and it was employed as a special dispersant of matrix solid-phase dispersion for selective extraction of fluoroquinolones (ofloxacin, ciprofloxacin and enrofloxacin) and xanthine (caffeine and theophylline) from human serum samples. To eliminate the influences of template leaking on quantitative analysis, acetonitrile-trifluoracetic acid (99:1, v/v) was used as the template removing solution. By using water and acetonitrile-trifluoracetic acid (99.5:0.5, v/v) as the washing and elution solvent, respectively, satisfactory recoveries and clean enough chromatogram could obtained. Good linearity of all the analytes was observed in a range of 0.35-150 μg g(-1) with the correlation coefficient (r(2))≥0.9991. The recoveries of spiked human serum samples were in a range of 89.5-104.0% for fluoroquinolones and xanthine derivatives with RSD less than of 5.0%.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 11/2011; 879(30):3551-5. · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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) (r(2)=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.
Talanta 09/2011; 85(4):2100-5. · 3.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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 CCl(4) (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 ngg(-1) with the correlation coefficient (r(2)) ≥ 0.9992. The limits of detection (LODs) based on signal to noise of 3 were 0.64-0.79 ngg(-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.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 09/2011; 879(25):2507-12. · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
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.
Journal of Separation Science 08/2011; 34(19):2668-73. · 2.73 Impact Factor
