Qiaomei Lu

Fuzhou University, Min-hou, Fujian, China

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Publications (8)24.82 Total impact

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    ABSTRACT: In this paper, water-miscible ionic liquid (IL) such as 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) is introduced for the first time as a novel multifunctional acceptor phase additive in hollow-fiber protected liquid phase microextraction (HF-LPME). For investigating the performances of [BMIM]Cl, it was respectively mixed with NaOH, HCl and deionized water. And their extraction performance was preliminary evaluated with alkaline compounds (clenbuterol, metoprolol, carteolol and propranolol), acidic compounds (diethylstilbestrol, hexestrol, phenol and bisphenol A) and neutral compounds (acenaphthylene, fluorene and fluoranthene). Furthermore, a complete extraction and determination method using IL-three phase HF-LPME and liquid chromatography was established for polycyclic aromatic hydrocarbons (PAHs) in river water. The extraction conditions, such as concentration of IL, extraction temperature, extraction time, stirring speed, ionic strength and the addition of methanol were studied in detail. Under the optimum conditions, the linear ranges of acenaphthylene, fluorene and fluoranthene were 1-100, 1-200 and 1-200 ng mL(-1), respectively. Limit of detections (LODs) were lower than 0.25 ng mL(-1). The recoveries of PAHs in three kinds of spiked real water are between 90.97 and 109.7% and the precisions are in the range of 2.53-7.01%. Since water-miscible ionic liquids had various forms, similar extraction capabilities to organic solvents and could be conveniently adjusted by acid, alkaline and buffer, this proposed method should have great potentiality in sample preparation of HF-LPME.
    Talanta 01/2012; 88:43-9. · 3.50 Impact Factor
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    ABSTRACT: A new pressure-assisted capillary electrochromatography coupled with electrospray ionization-mass spectrometry method using a silica-based monolithic column as separation media was developed for the analysis of β2-agonists in human urine. Experimental conditions including the mobile phase, separation voltage, assisted pressure, and sheath liquid were optimized for the analysis: mobile phase composed of 82% (v/v) ACN and 18% (v/v) 20mmol/L ammonium acetate (pH 6.0); separation voltage 25kV; assisted pressure 2bar; and the sheath liquid consisting of 7.5mmol/L acetic acid in isopropanol/water 50/50% (v/v) that was delivered at a flow rate of 3.0μL/min. Six β2-agonists were separated within 12.5min with LODs (defined as S/N=3) in the range of 0.25–2.0ng/mL. The absolute LODs of the developed method for analyzing six β2-agonists ranged from 5.75 to 46.0fg. Method repeatability of run-to-run and column-to-column was satisfactory. The recovery obtained from the analysis of spiked urine samples was between 88.2% and 106% with RSDs lower than 6.68%. The method was successfully applied to the analysis of real urine sample from volunteers.
    Talanta 06/2010; 81(4):1655-1661. · 3.50 Impact Factor
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    ABSTRACT: A pressure-assisted CEC with ESI-MS based on poly(1-hexadecene-co-trimethylolpropane trimethacrylate) monolithic column for rapid analysis of two beta(2)-agonists and three narcotics was established in this article. After the organic polymer-based monolithic column was prepared by an in-situ polymerization procedure, a systematic investigation of the pressure-assisted CEC separation and ESI-MS detection parameters was performed. Baseline separation of the studied analytes could be obtained using the solution containing 75% ACN v/v and 20 mmol/L ammonium acetate with pH 8.0 as running buffer, when applying separation voltage of 20 kV and assisted pressure of 5 bar. Under the optimized conditions, two beta(2)-agonists and three narcotics could be completely resolved and accurately determined within 15 min. Finally, the proposed method was successfully used for real urine samples detection.
    Electrophoresis 06/2010; 31(12):1991-7. · 3.16 Impact Factor
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    ABSTRACT: Pressurized CEC (pCEC) with UV detection was developed for the simultaneous analysis of endogenetic and ectogenic plant hormones. Effects of some crucial factors including mobile phase, buffer concentration, pH value and applied voltage on pCEC separation were investigated, respectively. Under the optimum conditions, namely a packed capillary column (3 microm Hypersil C(18), 45 cm total length with 100 microm id x 20 cm effective length) as the separation channel; ACN: 10 mmol/L phosphate (50:50, v/v, %) as the mobile phase, pH 4.0; pump flow rate 0.035 mL/min; separation voltage -10 kV; UV wavelength 222 nm, a complete separation of five hormones was accomplished. The pCEC assay presented good linearity (0.8-100 microg/mL), with LOD of 0.2 microg/mL and R in range of 0.998-0.999. Meanwhile, a lack-of-fit test was performed to evaluate these linear models. Results showed that no significant lack-of-fit was observed and these models were appropriate (alpha=0.05).
    Journal of Separation Science 03/2010; 33(4-5):651-7. · 2.59 Impact Factor
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    ABSTRACT: Auxin plays an important role in cell differentiation, apical dominance, and tropism in plants. A new method based on dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography-fluorescence detection (HPLC-FLD) has been established to detect auxin. A mixture of CHCl(3) (extraction solvent) and acetone (disperser solvent) was injected quickly into a sample solution with desired salt concentration and pH value, and then a cloudy solution consisting of many dispersed fine droplets of CHCl(3) was formed. After centrifugation, the sedimented phase was withdrawn and directly analyzed by HPLC-FLD. Under optimal conditions, four auxins were baseline separated within 3.5 min, with the minimal limit of detection of 0.02 ng mL(-1) and coefficient correlations in the range of 0.9980-0.9995. This simple method was successfully applied to real sample analysis. Experimental results showed that DLLME was a high-performance and powerful preconcentration method to extract and enrich related plant auxin.
    Journal of Agricultural and Food Chemistry 02/2010; 58(5):2763-70. · 3.11 Impact Factor
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    ABSTRACT: In this paper, a novel highly cross-linked porous monolithic stationary phase having a long alkyl chain ligand (C16) was introduced and evaluated in CEC. The monolithic stationary phase was prepared by in situ copolymerization of 1-hexadecene, trimethylolpropane trimethacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in the presence of ternary porogenic solvent (cyclohexanol/1,4-butanediol/water). In preparing monoliths, the ternary cross-linker trimethylolpropane trimethacrylate was usually applied to preparing molecularly imprinted polymers or molecularly imprinted solid-phase extraction, instead of binary cross-linker ethylene dimethacrylate. 1-Hexadecene was introduced to provide the non-polar sites (C16) for chromatographic retention, while AMPS was used to generate the EOF for transporting the mobile phase through the monolithic capillary. Monolithic columns were prepared by optimizing proportion of porogenic solvent and AMPS content in the polymerization solution as well as the cross-linkers. The monolithic stationary phases could generate a strong and stable EOF in various pH values and exhibit an RP-chromatographic behavior for neutral compounds. For charged compounds, the separation was mainly based on the association of hydrophobic, electrostatic and electrophoretic interaction.
    Electrophoresis 10/2009; 30(20):3540-7. · 3.16 Impact Factor
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    ABSTRACT: The objective of this study was to prepare a coated capillary to achieve rapid analysis of peptides and amino acids (AAs) by CE-ESI-MS. The coated capillary was prepared by chemical modification of the fused silica (FS) capillary with 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) via a silanization reaction followed by an on-column in situ graft polymerization. In preparing capillary coating, AMPS was introduced for the following two purposes: first, to achieve strong and stable EOF in a wide pH range, and second, to obtain good repeatability of separations of peptides and AAs by reducing their adsorption to the FS capillary. The inner wall morphology, the characteristics of EOF, and the performances of coated capillary including separation ability, repeatability, and stability were investigated in detail and evaluated by analyses of four peptides (D-Ala-D-Ala, Gly-Gly-L-Leu, Gly-D-Phe, and L-Leu-D-Leu) and three AAs (glycine, glutamic acid, and phenylalanine), respectively. Under the optimized conditions, the analysis times of four peptides and three AAs in the coated capillary were 5.6 and 6.0 min, respectively, i.e. much shorter than those in the bare-FS capillary, 20 and 26 min, respectively. These coated capillaries were shown to be well suitable for CE coupling with ESI-MS to analyze peptides and AAs thanks to high separation power, short analysis times, good repeatability and high stability.
    Electrophoresis 08/2009; 30(13):2273-9. · 3.16 Impact Factor
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    ABSTRACT: Auxin is an important phylohormone, which regulates specific physiological responses such as division, elongation and differentiation of cells. A new method using liquid chromatography/electrospray ionization ion trap mass spectrometry (LC/ESI-ITMS) has been developed for identification and quantitation of four auxins. Under the optimum conditions, four auxins (indole-3-acetic acid, indole-3-propionic acid, indole-3-butyric acid and 1-naphthylacetic acid) were completely separated and quantitated within 7 min with a minimum detection limit of 8.0 ng mL(-1) with relative standard deviations lower than 5.0%. This method also has been applied to analysis of auxins in Chinese cabbage where, even with a complicated serious background perturbation due to the natural biological matrix, the mean recoveries ranged from 77.5% to 99.8%. Finally, we discuss the MS-relevant properties of the identified auxins in detail.
    Rapid Communications in Mass Spectrometry 08/2008; 22(16):2565-72. · 2.64 Impact Factor