Co-reporter:Huifang Zhang, Hui Xu
Journal of Chromatography A 2017 Volume 1521(Volume 1521) pp:
Publication Date(Web):27 October 2017
DOI:10.1016/j.chroma.2017.09.035
•Electrospun PS@PDA-Ag nanofibers were fabricated for online micro-solid phase extraction.•The nanofibers exhibited large surface area, high hydrophilicity and porosity, and good extraction efficiency.•A simple, rapid, sensitive and automated method was developed for the determination of urinary OH-PAHs.In this article, silver nanoparticles (AgNPs) modified nanofibers that represent a novel kind of packing materials for micro-solid phase extraction (μ-SPE) is reported for the first time. The composite material was fabricated through in-situ formation of AgNPs on the polydopamine (PDA) coated polystyrene electrospun fibers (PS@PDA-Ag). The nanofibers displayed desirable hydrophilicity, large surface area, high porosity, good extraction ability and certain capacity to resist matrix interference. A μ-SPE combined with liquid chromatography-mass spectrometry (LC–MS) method was developed for the online determination of three monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) metabolites in human urine. Under the optimal conditions, good linearity (0.02–5 ng mL−1) was acquired with the correlation coefficients (R2) being larger than 0.9962. Low limits of detection (0.007–0.032 ng mL−1) expressed the satisfactory sensitivity of the method. Moreover, the intraday relative standard deviation values lower than 9.7% and the recoveries among the range of 71–116% were obtained. In general, the online μ-SPE-LC–MS method had the features of simplicity, rapidity, sensitivity and automation, and it was expected to become a promising approach for the online analysis of trace OH-PAHs in complex biological samples.
Co-reporter:Yu Li;JingHong Li
RSC Advances (2011-Present) 2017 vol. 7(Issue 20) pp:11959-11968
Publication Date(Web):2017/02/16
DOI:10.1039/C6RA25453E
In this work, a graphene/polyaniline (G/PANI) electrodeposited coating was introduced as a novel extraction phase of needle trap microextraction (NTME). The needle trap coating was prepared by in situ electrodepositing G/PANI on the inner surface of a 21-gauge stainless steel needle, and utilized for the dynamic extraction of volatile organic compounds (VOCs) from human exhaled breath vapor (EBV) and headspace gas in cell lines. The coating exhibited enhanced mechanical stability, long lifespan, large specific surface area and good biocompatibility. The parameters for the extraction and analysis of analytes including extraction mode, sampling temperature, sampling speed, desorption parameters (temperature and time) were evaluated and optimized. The extraction performance of the needle trap was also compared with three commercially available SPME fibers. Low detection limits (0.002–0.003 μg L−1) and good linearity (R2 ≥ 0.9905) were obtained for the analysis of eight VOCs. The developed needle trap microextraction-gas chromatography-mass spectrometry (NTME-GC-MS) method has been successfully applied to the analysis of VOCs from human exhaled breath and lung cancer cell lines (A549) with good recovery (70–120%) and acceptable reproducibility (relative standard deviation: intra-day 4.8–15.3%, inter-day, 4.2–14.3%). The proposed method is simple, sensitive and environmentally friendly, it provides a new possibility for the determination of VOCs of exhaled breath both in vivo and in vitro.
Co-reporter:Feilong Liu, Hui Xu
Talanta 2017 Volume 162() pp:261-267
Publication Date(Web):1 January 2017
DOI:10.1016/j.talanta.2016.09.065
•A novel PS/MOF-199 nanofiber was fabricated for TFME-HPLC.•The adsorbent exhibited excellent stability, extraction capacity and high hydrophobicity.•Good results were obtained for sensitivity, precision, accuracy and speed.•The method was applied in biomonitoring of aldehydes in urine.In this work, electrospun polystyrene/metal-organic frameworks-199 (PS/MOF-199) nanofiber film was synthesized and investigated as a novel adsorbent for thin film microextraction (TFME) of aldehydes in human urine. Some properties of the prepared PS/MOF-199 nanofiber film, including morphology, structure, wettability, solvent stability and extraction performance were studied systematically. Porous fibrous structure, large surface area, good stability, strong hydrophobicity and excellent extraction efficiency were obtained for the film. Based on the PS/MOF-199 film, a thin film microextraction-high performance liquid chromatography (TFME-HPLC) method was developed, and the experimental parameters that affected the extraction and desorption were optimized. Under the optimal conditions, the limits of detection (LODs) were in the range of 4.2–17.3 nmol L−1 for the analysis of six aldehydes. Good linearity was achieved with correlation coefficients (R2) being lager than 0.9943. Satisfactory recovery (82–112%) and acceptable reproducibility (relative standard deviation: 2.1–13.3%) were also obtained for the method. The developed TFME-HPLC method has been successfully applied to the analysis of aldehyde metabolites in the urine samples of lung cancer patients and healthy people. The method possesses the advantages of simplicity, rapidity, cost-effective, sensitivity and non-invasion, it provides an alternative tool for the determination of aldehydes in complex sample matrices.
Co-reporter:Huifang Zhang, Sheng Hu, Dandan Song, Hui Xu
Analytica Chimica Acta 2016 Volume 943() pp:74-81
Publication Date(Web):2 November 2016
DOI:10.1016/j.aca.2016.09.028
•An electrospun PS/G@PDA nanofiber membrane was fabricated for thin film microextraction.•The membrane exhibited satisfactory hydrophilicity, large surface area, high extraction efficiency and special selectivity.•A fast, convenient, sensitive, high-efficient and matrix-free method was developed.•The method was applied for the determination of urinary aldehyde metabolites.In this paper, a novel polydopamine modified polystyrene/graphene electrospun nanofiber membrane (PS/G@PDA) was fabricated on the surface of filter paper and used for thin film microextraction (TFME) for the first time. Benefiting from the hydrophilic polydopamine (PDA) coating and the porous fibrous structure, the PS/G@PDA membrane exhibited large surface area, high extraction efficiency, rapid extraction equilibrium, special selectivity and excellent biocompatibility. A thin film microextraction-high performance liquid chromatography method was developed and applied for the analysis of six aldehyde metabolites in human urine samples. Under the optimal conditions, the recoveries of the aldehyde compounds varied in the range of 83%–115%, with the relative standard deviation values lower than 14.5% (n = 5). Moreover, satisfactory sensitivities with the limits of detection in the range of 2.3–6.5 nmol L−1 and good linearity with excellent correlation coefficients (R2) being larger than 0.9936 had also been achieved. In general, a fast, convenient, sensitive, high-efficient and matrix-free method was successfully proposed and expected becoming a promising approach for the determination of trace aldehyde metabolites in complex biological samples.
Co-reporter:Feilong Liu;Dan Song;Xueying Huang
Journal of Separation Science 2016 Volume 39( Issue 7) pp:1326-1330
Publication Date(Web):
DOI:10.1002/jssc.201501182
The aim of this work is to develop a simple phase-transfer method for dispersive liquid–liquid microextraction. For this purpose, a polystyrene nanofiber was prepared by a facile electrospinning strategy and used for the first time as an adsorbent to transfer the organic phase in dispersive liquid–liquid microextraction procedure. The fiber was characterized and its chemical stability and excellent hydrophobicity enable it to selectively adsorb the organic solvent in an aqueous sample. High porosity and specific surface area provide a large adsorption capacity. Under the optimal conditions, the developed dispersive liquid–liquid microextraction with high-performance liquid chromatography method was successfully applied to the analysis of aldehydes in environmental water samples. The merits of this approach are that it is easy-to-operate, low-cost, time-saving, and has satisfactory sensitivity. It provides an alternative way for fast and convenient phase transfer of the hydrophobic organic solvent from the aqueous phase.
Co-reporter:Yu Li, Hui Xu
Journal of Chromatography A 2015 Volume 1395() pp:23-31
Publication Date(Web):22 May 2015
DOI:10.1016/j.chroma.2015.03.058
•A G/PANI coating-based on-line IT-SPME method was developed for breath analysis.•The coating exhibited excellent stability, lifespan, extraction capacity and selectivity.•Good results were obtained for sensitivity, precision, accuracy and matrix effect.•The proposed breath analysis method is automatic and non-invasive.In this work, we introduced a novel graphene/polyaniline (G/PANI) electrodeposited coating for on-line in-tube solid phase microextraction (IT-SPME) for the first time. The G/PANI coating was prepared on the internal surface of stainless steel tube by a facile in-situ electrodeposition method. The morphology and formation of the composite coating were confirmed by scanning electronic microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Some important experimental parameters that could affect the extraction and separation such as the coating thickness, internal diameter of tube, sampling flow rate as well as sample volume were optimized. The extraction performance of the IT-SPME coating was evaluated systematically. The coating exhibited enhanced mechanical stability, long lifespan, large specific surface area and good biocompatibility compared with polyaniline coating. The on-line IT-SPME method showed higher enrichment efficiency, faster analysis speed and higher automation level than off-line manual mode. Six aldehydes were determined simultaneously with low limits of detection of 0.02–0.04 nmol L−1 and good linearity (R2 ≥ 0.9920). The method has been applied successfully for the determination of aldehydes in human exhaled breath condensates with good recovery (70–120%) and satisfied reproducibility (relative standard deviation: 1.1–11.9%). This on-line IT-SPME method provides a promising approach for the determination of trace aldehydes with approving sensitivity in human exhaled breath condensates.
Co-reporter:GuoJuan Zhang, LiangYuan Zou, Hui Xu
Talanta 2015 Volume 132() pp:528-534
Publication Date(Web):15 January 2015
DOI:10.1016/j.talanta.2014.09.035
•A highly ordered nanoporous anodic alumina coating was prepared as a novel extraction phase of solid phase microextraction.•Excellent extraction efficiency and good thermal and mechanical stability are remarkable advantages of the coating.•The simple, convenience and non-invasive method was applied successfully to human exhaled breath analysis.The objective of the study is to develop a facile and highly sensitive solid phase microextraction-gas chromatography/mass spectrometry method for the analysis of volatile organic compounds in human exhaled breath vapor. For the purpose, a highly ordered nanoporous anodic alumina coating was prepared by a two-step anodic oxidization method based on aluminum substrate. To have a good knowledge of the fiber, some features were characterized and the results indicate that the coating has several advantages, including excellent chemical and thermal stability, high mechanical strength, large surface area and good extraction performance. In addition, some parameters related to extraction efficiency were also studied. Under the optimal conditions, the coating was used to quantitatively extract volatile organic compounds. Good linearity and wide linear range were obtained with correlation coefficients (R2) ranging from 0.9933 to 0.9999. The detection limits of benzene homologues, aldehydes and ketones were between 0.7 and 3.4 ng L−1. Relative standard deviations (n=5) ranged from 1.8 to 15.0%. Satisfied recovery (89–115%) was obtained at two spiked concentration levels. Finally, the developed method was successfully applied for the analysis of volatile organic compounds in human exhaled vapor samples of lung cancer patients and the controls, and the results were statistically analyzed with Independent-Sample T Test. The proposed method exhibits some outstanding merits, including convenience, non-invasion, low cost and sensitivity. It provides a potential tool for rapid detection of volatile organic compounds in human exhaled breath.
Co-reporter:Shuling Wang;Xuelan Wang;Yijun Ren
Chromatographia 2015 Volume 78( Issue 9-10) pp:621-629
Publication Date(Web):2015 May
DOI:10.1007/s10337-015-2872-4
In this study, metal–organic framework (MOF)-199 was in situ grown on
the surface of stainless steel mesh by a facile one-step hydrothermal synthesis strategy. A piece of the MOF-199-coated film was used as adsorbent in thin-film extraction. With octahedral shape, accessible macropores, and high surface area-to-volume, the MOF-199 coating exhibited excellent extraction ability and enhanced mass transfer rate toward six studied aldehydes. The proposed thin-film extraction-high-performance liquid chromatography method was applied successfully for the determination of aldehyde in human exhaled breath condensates of lung cancer patients and healthy people. The experimental conditions were optimized systematically. Under the optimal conditions, a wide linear application range was obtained with linear correlations (r) above 0.995; the limits of detection were from 1.3 to 20.3 nmol L−1. Reasonable recoveries were achieved between 74 and 120 %. The method possesses the potential advantages of simple setup, convenient operation, fast analysis and factory sensitivity, and little matrix interference. It supplies us with a new possibility for non-invasive monitoring of trace aldehyde metabolites in complex biological samples.
Co-reporter:Hui Xu, Yanling Wei, Linli Zhu, Jing Huang, Yu Li, Feilong Liu, Shuling Wang, Shi Liu
Journal of Chromatography A 2014 Volume 1324() pp:29-35
Publication Date(Web):10 January 2014
DOI:10.1016/j.chroma.2013.11.041
•A bifunctional magnetic nanoparticles were synthesized.•The material is suitable for biological sample analysis.•A simple and sensitive method was developed for analysis of aldehydes in exhaled breath condensate.We report here the preparation of dual-functionalized magnetic nanoparticles, with the nanoparticles as extraction sorbents, a magnetic solid phase extraction method was developed and applied for the analysis of trace amount of aldehydes in human exhaled breath condensate. In the material, octyl-functionalized internal surface provided hydrophobic groups for extraction, non-ionic surfactant (Tween-20)-coated outer surface offered hydrophilic network structure to prevent the access of macromolecules, strong magnetic property of nanoparticles simplified the analytical procedure. The experimental results showed that the prepared nanoparticles exhibited good dispersibility in aqueous solution and excellent extraction efficiency toward aldehydes. Six aldehydes were derivatized with 2,4-dinitrophenylhydrazine and then the formed hydrazones were extracted by the nanoparticles and analyzed by high-performance liquid chromatography–photo diode array detector. Under the optimal conditions, the method provided low limits of detection (2.9–21.5 nmol L−1), satisfactory reproducibility (relative standard deviations, 2.9–13.1%) and acceptable recoveries (73.7–133.1%). The developed method was applied successfully to determine the aldehydes metabolites in the exhaled breath condensate samples of healthy people and lung cancer patients. The dual-functionalized material is suitable for biological sample analysis. The proposed method provides an alternative approach for quantification of aldehyde metabolites in complex biological samples.
Co-reporter:Linli Zhu
Journal of Separation Science 2014 Volume 37( Issue 18) pp:2591-2598
Publication Date(Web):
DOI:10.1002/jssc.201400363
Detection of monohydroxy polycyclic aromatic hydrocarbons metabolites in urine is an advisable and valid method to assess human environmental exposure to polycyclic aromatic hydrocarbons. In this work, novel Fe3O4/graphene oxide composites were prepared and their application in the magnetic solid-phase extraction of monohydroxy polycyclic aromatic hydrocarbons in urine was investigated by coupling with liquid chromatography and mass spectrometry. In the hybrid material, superparamagnetic Fe3O4 nanoparticles provide fast separation to simplify the analytical process and graphene oxide provides a large functional surface for the adsorption. The prepared magnetic nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. The experimental conditions were optimized systematically. Under the optimal conditions, the recoveries of these compounds were in the range of 98.3–125.2%, the relative standard deviations ranged between 6.8 and 15.5%, and the limits of detection were in the range of 0.01–0.15 ng/mL. The simple, quick, and affordable method was successfully used in the analysis of human urinary monohydroxy polycyclic aromatic hydrocarbons in two different cities. The results indicated that the monohydroxy polycyclic aromatic hydrocarbons level in human urine can provide useful information for environmental exposure to polycyclic aromatic hydrocarbons.
Co-reporter:GuoJuan Zhang, XiaoXi Guo, ShuLing Wang, XueLan Wang, YanPing Zhou, Hui Xu
Journal of Chromatography B 2014 Volume 969() pp:128-131
Publication Date(Web):15 October 2014
DOI:10.1016/j.jchromb.2014.08.016
•A novel graphene fiber coating was prepared for the enrichment of volatile organic compounds.•The fiber exhibited remarkable thermal and mechanical stability, long lifespan and excellent extraction efficiency.•The simple and non-invasive method was applied successfully to human exhaled breath analysis.In the work, a novel graphene-based solid phase microextraction-gas chromatography/mass spectrometry method was developed for the analysis of trace amount of volatile organic compounds in human exhaled breath vapor. The graphene fiber coating was prepared by a one-step hydrothermal reduction reaction. The fiber with porous and wrinkled structure exhibited excellent extraction efficiency toward eight studied volatile organic compounds (two n-alkanes, five n-aldehydes and one aromatic compound). Meanwhile, remarkable thermal and mechanical stability, long lifespan and low cost were also obtained for the fiber. Under the optimal conditions, the developed method provided low limits of detection (1.0–4.5 ng L−1), satisfactory reproducibility (3.8–13.8%) and acceptable recoveries (93–122%). The method was applied successfully to the analysis of breath samples of lung cancer patients and healthy individuals. The unique advantage of this approach includes simple setup, non-invasive analysis, cost-efficient and sufficient sensitivity. The proposed method supply us a new possibility to monitor volatile organic compounds in human exhaled breath samples.
Co-reporter:Hui Xu, Shuyu Wang
Analytica Chimica Acta 2012 Volume 724() pp:61-66
Publication Date(Web):29 April 2012
DOI:10.1016/j.aca.2012.02.046
In this study, a porous polypropylene frit was coated with polydimethylsiloxane (PDMS) as extraction medium, based on the home-made PDMS-frit, a rapid, simple and sensitive sorptive extraction method was established for analysis of potential biomarkers of lung cancer (hexanal and heptanal) in human serum samples. In the method, derivatization and extraction occurred simultaneously on the PDMS-frit, then the loaded frit was ultrasonically desorbed in acetonitrile. Polymerization, derivatization–extraction and desorption conditions were optimized. Under the optimal conditions, satisfactory results were gained, a wide linear application range was obtained in the range of 0.002–5.0 μmol L−1 (R > 0.997) for two aldehydes, the detection limits (S N−1 = 3) were 0.5 nmol L−1 for hexanal and 0.4 nmol L−1 for heptanal. The relative standard deviations (RSDs, n = 5) of the method were below 7.9% and the recoveries were above 72.7% for the spiked serum. All these results hint that the proposed method is potential for disease markers analysis in complex biological samples.Graphical abstractHighlights► Porous polypropylene frit was used as a support of PDMS coating. ► Method was established for analysis of aldehydes biomarkers in human serum samples. ► Compared with SBSE, the developed method is simple, labor-saving, rapid, robust and sensitive. ► It enables effective cleanup of sample matrix simultaneously with enrichment of target analytes.
Co-reporter:Hui Xu;Zhihua Yan ;Dan Song
Journal of Separation Science 2012 Volume 35( Issue 5-6) pp:713-720
Publication Date(Web):
DOI:10.1002/jssc.201100908
In this paper, a polypropylene frit with porous network structure and high area-to-thickness ratio (4.8 mm diameter, 1.6 mm thickness, 20 mm pore size) was utilized as a mould of monolith. Poly(methacrylic acid-ethlyene glycol dimethacrylate) (MAA-EGDMA) monolith was in situ synthesized in the micro-channel of frit by photopolymerization. A monolith frit-based solid-phase microextraction method (SPME) was developed for the determination of hexanal and heptanal in serum samples by combining with high-performance liquid chromatography. 2,4-Dinitrophenylhydrazine (DNPH) as the derivatizing reagent was absorbed on a monolith frit, then its derivatization reaction with aldehydes and the absorption of formed hydrazones on the monolith disk occurred simultaneously. The condition parameters for polymerization, derivatization and extraction were optimized systematically. Under the optimum conditions, rigid structure, low back-pressure and high column capacity were achieved for the monolith frit. The limits of detection for hexanal and heptanal were 1.86 and 1.38 nmol/L, respectively. The inter- and intra-day relative standard deviations were less than 7.7% (n = 6). This method was applied successfully to aldehydes analysis in human serum samples. The method possesses advantages such as simplicity, efficiency, low cost and good biocompatibility. It provides an alternative approach for quantification of aldehydes in complex biological samples.
Co-reporter:Hui Xu, Xiaoman Sun and Dandan Song
Analytical Methods 2012 vol. 4(Issue 12) pp:4161-4167
Publication Date(Web):02 Nov 2012
DOI:10.1039/C2AY25918D
In this study, a polypropylene sieve with porous network structure was coated with polydimethylsiloxane (PDMS) and used as extraction phase. Based on the PDMS-sieve, a rapid, simple and sensitive sorptive extraction method was established for analysis of five pyrethroid residues in tea samples. In the method, pyrethroids in a stirred solution were extracted on a PDMS-sieve, the analytes loaded on the sieve were then ultrasonically desorbed in ethyl acetate and analyzed by gas chromatography-mass spectrometer (GC-MS) with selected ion monitoring mode (SIM). The proposed method was optimized and validated, the matrix-matched calibration curves were performed at six concentration levels and good linear correlations (r) were obtained (r ≥ 0.9907) within the range of 0.001–0.1 μg mL−1. The detection limits (LODs) of five pesticides ranged from 0.8 ng g−1 to 19.6 ng g−1. Good repeatability was obtained with the inter- and intra-day relative standard deviation (RSDs) values lower than 10%. The method has been applied successfully to the determination of pyrethroids in six tea samples, and satisfactory recoveries ranging from 82% to 111% were obtained. The results indicated that the proposed method is suitable for trace analysis of pesticides residues in tea samples.
Co-reporter:Hui Xu, Shuyu Wang, Ganbing Zhang, Shiqiang Huang, Dandan Song, Yanping Zhou, Guangdou Long
Analytica Chimica Acta 2011 Volume 690(Issue 1) pp:86-93
Publication Date(Web):25 March 2011
DOI:10.1016/j.aca.2011.02.006
In this work, a polypropylene frit with porous network structure (20 μm pole size) was first utilized as the mould of polymer monolithic material, poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EDMA) monolith was synthesized within channels and macropores of the frit. A simple and sensitive solid-phase microextraction method based on polymer monolith frit coupled with high-performance liquid chromatography (HPLC) was established and applied to analysis of hexanal and heptanal in biological samples (human urine and serum). In the method, small molecule metabolites (aldehydes) in biological samples derivatized with 2,4-dinitrophenylhydrazine (DNPH), and the formed hydrazones were extracted simultaneously on the monolithic frit and thereafter ultrasound-assisted desorbed with acetonitrile as elution solvent. The experimental parameters with regard to polymerization, derivatization and extraction were investigated. Under the optimal conditions, the linearity was in the range of 0.02–5.0 μmol L−1 (r = 0.9994) for both hexanal and heptanal and the limits of detection (S/N = 3) were 0.81 nmol L−1 for hexanal and 0.76 nmol L−1 for heptanal. The relative standard deviations (RSDs, n = 5) were less than 6.5% for the same monolithic frit and less than 8.9% for the different monolithic frits. Satisfactory recoveries ranging from 70.71% to 88.73% were obtained for the urine samples. The method possesses many advantages including simple setup, fast analysis, low cost, sufficient sensitivity, good biological compatibility and less organic solvent consumption. The proposed method is a useful assistant tool in the clinical early diagnosis of lung disease by monitoring aldehyde biomarker candidates in complex biological samples.
Co-reporter:Dandan Song, Yanqin Gu, Lu Liang, Zhihui Ai, Lizhi Zhang and Hui Xu
Analytical Methods 2011 vol. 3(Issue 6) pp:1418-1423
Publication Date(Web):24 May 2011
DOI:10.1039/C1AY05102D
In this work, a new magnetic solid-phase extraction (MSPE) method based on C8-amine-Fe3O4 magnetic nanoparticles (MNPs) was developed for the determination of aldehyde biomarkers (hexanal and heptanal) in human urine samples. Hexanal and heptanal were derivatized with 2,4-dinitrophenylhydrazine (DNPH) in an acidic solution and then the formed aldehyde derivatives were extracted by the MNPs. After eluting and simple magnetic separation, the supernatant containing the two target analytes was transferred for HPLC analysis. The effects of various experimental parameters on the derivatization and extraction efficiency were investigated and optimized. Under the optimal conditions, good linearity was obtained in the concentration range of 0.005–5 μmol L−1 (r > 0.9982). The limits of detection (LOD) for hexanal and heptanal were 1.87 and 0.78 nmol L−1, respectively. The average recoveries of urine samples of healthy humans ranged from 82.5% to 99.4% with the inter- and intra-day precisions (n = 6) less than 8.4%. Because of the excellent magnetic responsibility and high dispersibility of the MNPs, the proposed method was shown to be simple and rapid. Besides, this method possesses advantages such as low-cost, efficiency and good reproducibility.
Co-reporter:Hui Xu, Lili Lv, Sheng Hu, Dandan Song
Journal of Chromatography A 2010 Volume 1217(Issue 16) pp:2371-2375
Publication Date(Web):16 April 2010
DOI:10.1016/j.chroma.2009.09.068
In this paper, an ultrasound-assisted headspace liquid-phase microextraction with in-drop derivatization was developed for the extraction and determination of hexanal and heptanal as the biomarkers in human blood. In the method, a polychloroprene rubber (PCR) tube was utilized as container to load extraction solvent (methyl cyanide) and derivatization reagent (2,4-dinitrophenylhydrazine, 2,4-DNPH). Volatile aldehydes were headspace extracted and simultaneously derivatized in the droplet, followed by LC-UV detection of the formed hydrazones. The stability of organic solvent and the sensitivity of the method enhanced greatly. Under the optimal conditions, good linearity was obtained in the concentration range of 0.01–10 μmol L−1 (r > 0.997) and the limits of detection (LOD) for hexanal and heptanal were 0.79 and 0.80 nmol L−1, respectively. The recoveries in blood sample ranged from 75.2% to 101.1% with the inter- and intra-day precisions less than 9.8%. The method possesses the advantages such as simplicity, sensitivity, efficiency, low consumption of solvent, and little interference from sample matrix. It provides great potential for the investigation of volatile disease biomarkers (aldehydes) in complex biological samples.
Co-reporter:Lv Lili, Hui Xu, Dandan Song, Yanfang Cui, Sheng Hu, Ganbing Zhang
Journal of Chromatography A 2010 Volume 1217(Issue 16) pp:2365-2370
Publication Date(Web):16 April 2010
DOI:10.1016/j.chroma.2010.01.081
A new dispersive liquid–liquid microextraction based on solidification of floating organic droplet method (DLLME-SFO) was developed for the determination of volatile aldehyde biomarkers (hexanal and heptanal) in human blood samples. In the derivatization and extraction procedure, 2,4-dinitrophenylhydrazine (DNPH) as derivatization reagent and formic acid as catalyzer were injected into the sample solution for derivatization with aldehydes, then the formed hydrazones was rapidly extracted by dispersive liquid–liquid microextraction with 1-dodecanol as extraction solvent. After centrifugation, the floated droplet was solidified in an ice bath and was easily removed for analysis. The effects of various experimental parameters on derivatization and extraction conditions were studied, such as the kind and volume of extraction solvent and dispersive solvent, the amount of derivatization reagent, derivatization temperature and time, extraction time and salt effect. The limit of detections (LODs) for hexanal and heptanal were 7.90 and 2.34 nmol L−1, respectively. Good reproducibility and recovery of the method were also obtained. The proposed method is an alternative approach to the quantification of volatile aldehyde biomarkers in complex biological samples, being more rapid and simpler and providing higher sensitivity compared with the traditional dispersive liquid–liquid microextraction (DLLME) methods.
Co-reporter:Hui Xu, Zongqing Ding, Lili Lv, Dandan Song, Yu-Qi Feng
Analytica Chimica Acta 2009 Volume 636(Issue 1) pp:28-33
Publication Date(Web):16 March 2009
DOI:10.1016/j.aca.2009.01.028
A new dispersive liquid–liquid microextraction based on solidification of floating organic droplet method (DLLME-SFO) was developed for the determination of five kinds of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. In this method, no specific holder, such as the needle tip of microsyringe and the hollow fiber, is required for supporting the organic microdrop due to the using of organic solvent with low density and proper melting point. Furthermore, the extractant droplet can be collected easily by solidifying it in the lower temperature. 1-Dodecanol was chosen as extraction solvent in this work. A series of parameters that influence extraction were investigated systematically. Under optimal conditions, enrichment factors (EFs) for PAHs were in the range of 88–118. The limit of detections (LODs) for naphthalene, diphenyl, acenaphthene, anthracene and fluoranthene were 0.045, 0.86, 0.071, 1.1 and 0.66 ng mL−1, respectively. Good reproducibility and recovery of the method were also obtained. Compared with the traditional liquid-phase microextraction (LPME) and dispersive liquid–liquid microextraction (DLLME) methods, the proposed method obtained about 2 times higher enrichment factor than those in LPME. Moreover, the solidification of floating organic solvent facilitated the phase transfer. And most importantly, it avoided using high-density and toxic solvent in the traditional DLLME method. The proposed method was successfully applied to determinate PAHs in the environmental water samples. The simple and low-cost method provides an alternative method for the analysis of non-polar compounds in complex environmental water.
Co-reporter:Hui Xu;Dandan Song;Yanfang Cui;Sheng Hu;Qiong-Wei Yu;Yu-Qi Feng
Chromatographia 2009 Volume 70( Issue 5-6) pp:775-781
Publication Date(Web):2009 September
DOI:10.1365/s10337-009-1208-7
A new analytical approach, simultaneous derivatization and dispersive liquid–liquid microextraction followed by liquid chromatography–atmospheric-pressure chemical ionization tandem mass spectrometry, has been developed for analysis of hexanal and heptanal in human blood. In the derivatization and extraction procedure a solution of 2,4-dinitrophenylhydrazine (derivatization reagent) in 85 μL acetonitrile (dispersive solvent) and 50 μL tetrachloromethane (extraction solvent) was rapidly injected into the aqueous sample containing hexanal and heptanal. Within a few seconds the aldehydes were derivatized and simultaneously extracted. After centrifugation, the hydrazones in the sediment phase were analyzed by LC–APCI–MS–MS. Derivatization and extraction conditions were investigated systematically. Under the optimum conditions enrichment factors for hexanal and heptanal in a 1-mL sample were 63 and 73, respectively. The calibration plots were linear in the ranges 0.5–100 and 100–1,000 nmol L−1, respectively, and the respective limits of detection (LOD) were 0.17 and 0.076 nmol L−1. Reproducibility and recovery were good. The experimental results were compared with those obtained by use of solid-phase extraction and polymer monolithic microextraction. Because sample derivatization, extraction, and concentration were combined in a single step, the proposed method enabled simple, rapid, inexpensive, and efficient analysis of aldehydes in blood. The method has great potential for clinical analysis of biologically relevant aldehydes.
Co-reporter:Jinrong Yao, Hui Xu, Lili Lv, Dandan Song, Yangfang Cui, Taozhi Zhang, Yu-Qi Feng
Analytica Chimica Acta 2008 Volume 616(Issue 1) pp:42-48
Publication Date(Web):26 May 2008
DOI:10.1016/j.aca.2008.04.007
A novel liquid-phase microextraction (LPME) method was presented in this paper. The most attractive feature of this method is using a polychloroprene rubber tube (PCR tube) instead of a microsyringe to load organic solvent. The PCR tube and sample vial were horizontally placed so that the selection of organic solvent was not affected by the density of extractant. Therefore, the stability of organic solvent increased and the available organic solvent was extended greatly. In this work, three phthalate esters (PAEs) (dimethyl phthalate (DMP), diethyl phthalate (DEP), and di-n-butyl phthalate (DnBP)) were chosen as model analytes to testify the feasibility of the new method. A series of extraction parameters have been investigated systematically. Under the optimized condition, the method showed linear response over four orders of magnitude, ranged from 0.005 mg L−1 to 50 mg L−1. The correlation coefficients (r) were better than 0.997 and the limits of detection (LOD) were 0.0012 mg L−1 for DMP, 0.0014 mg L−1 for DEP and 0.0022 mg L−1 for DnBP. Good reproducibility of extraction was acquired, the inter-day and intra-day relative standard deviation (R.S.D.) were below 7.9% and 7.4%, respectively. Recoveries that ranged from 82.7% to 116.9% were gained when the new method was used to determine three phthalate esters in landfill leachates. The enrichment factors were 5–26 for the three PAEs. The novel LPME is promising to be an alternative sample preparation method for extracting target analytes in complex sample matrices because of the simplicity, low cost and short sample preparation time.
Co-reporter:Wenhui Pan, Hui Xu, Yanfang Cui, Dandan Song, Yu-Qi Feng
Journal of Chromatography A 2008 Volume 1203(Issue 1) pp:7-12
Publication Date(Web):29 August 2008
DOI:10.1016/j.chroma.2008.07.004
An improved liquid–liquid–liquid microextraction (LLLME) technique has been put forward based on the principle of single drop LLLME. In the technique, a vial insert was firstly utilized as acceptor phase container. Because the diameter of the bottom of the vial insert was small, the contact area between the acceptor phase and the vial insert was bigger than that between microsyringe and microdrop of acceptor phase in single drop LLLME, and the stability of microdrop was increased markedly. More acceptor phase could be held in the improved method than that in single drop LLLME, and the sensitivity of the method was increased. The sample vial and vial insert were horizontally placed so that the density of organic solvent has little effect on the selection of organic solvents. Aqueous ammonia and toluene were selected as the acceptor phase and the organic phase, respectively. The improved method was successfully applied to determine four phenolic compounds in real aqueous samples. Good recoveries that ranged from 82.2% to 117.2% were obtained. The intra-day and inter-day reproducibilities (RSD) were under 4.8% and 6.8%, respectively. The extraction efficiency of the improved method was 11–47 times higher than that of single drop LLLME method. The improved LLLME method is economical, rapid, simple, efficient, low organic solvent consumption and no cross-containment. This method is very suitable for the extraction of ionizable and chargeable analyte in complex environmental or biological samples.
Co-reporter:Hui Xu;Jinrong Yao;Jing Cheng;Yanfang Cui;Dandan Song;Yuqi Feng
Chromatographia 2008 Volume 68( Issue 3-4) pp:235-238
Publication Date(Web):2008 August
DOI:10.1365/s10337-008-0686-3
An ultrasound-assisted headspace liquid microextraction method is presented. The organic solvent droplet is suspended at the bottom of a polychloroprene rubber tube. More extractant can be held and the stability of microdrop is better than by using a syringe needle so that extraction aided by ultrasonication can be carried out. Compared with traditional methods, the extraction efficiency is about ten times higher. The method has been used to determine phenols in real water samples, and good recoveries were obtained. It is a promising alternative for analyzing volatile or semivolatile pollutants in environmental samples due to its simplicity, rapidity and stability.
Co-reporter:Hui Xu, Wenhui Pan, Dandan Song and Guangfu Yang
Journal of Agricultural and Food Chemistry 2007 Volume 55(Issue 23) pp:9351-9356
Publication Date(Web):October 23, 2007
DOI:10.1021/jf0718345
An improved liquid phase microextraction (LPME) technique has been developed. As part of this technique, analytes were extracted into an extractant microdrop which was laid on the cone-shaped bottom of a PCR tube (polychloroprene rubber tube) but not at the needle tip of a microsyringe, and the sample vial and PCR tube were horizontally placed so that the extractant was not affected by the force of vertical orientation (gravity and floating force). The stability of the extractant microdrop increased greatly, and the selection of extractant was extended. In this work, flumetsulam and its two analogous herbicides were chosen as model analytes in investigating the feasibility of the new pretreatment method by coupling it to high-performance liquid chromatography (HPLC). Under the optimized experimental conditions, the linear range and the limits of detection (S/N = 3) were 0.01–5 µg/mL (r = 0.9997) and 0.8 ng/mL for flumetsulam, 0.002–5 µg/mL (r = 0.9994) and 0.5 ng/mL for analogue 1, and 0.002–1 µg/mL (r = 0.9993) and 0.5 ng/mL for analog 2, respectively. The inter- and intraday reproducibilities (RSD) were below 5.3 and 4.5%, respectively. Good recoveries that ranged from 79.4 to 115.0% were obtained in the analysis of real soil samples. The extraction efficiency of the improved method was 4–8 times higher than that of the conventional liquid phase microextraction method. The novel, simple, rapid, sensitive technique is very suitable for extraction of apolar and medium polar analyte in complex environmental samples.
Co-reporter:JingHong Li, Hui Xu
Talanta (15 May 2017) Volume 167() pp:623-629
Publication Date(Web):15 May 2017
DOI:10.1016/j.talanta.2017.03.005
Co-reporter:Dandan Song, Yanqin Gu, Lu Liang, Zhihui Ai, Lizhi Zhang and Hui Xu
Analytical Methods (2009-Present) 2011 - vol. 3(Issue 6) pp:NaN1423-1423
Publication Date(Web):2011/05/24
DOI:10.1039/C1AY05102D
In this work, a new magnetic solid-phase extraction (MSPE) method based on C8-amine-Fe3O4 magnetic nanoparticles (MNPs) was developed for the determination of aldehyde biomarkers (hexanal and heptanal) in human urine samples. Hexanal and heptanal were derivatized with 2,4-dinitrophenylhydrazine (DNPH) in an acidic solution and then the formed aldehyde derivatives were extracted by the MNPs. After eluting and simple magnetic separation, the supernatant containing the two target analytes was transferred for HPLC analysis. The effects of various experimental parameters on the derivatization and extraction efficiency were investigated and optimized. Under the optimal conditions, good linearity was obtained in the concentration range of 0.005–5 μmol L−1 (r > 0.9982). The limits of detection (LOD) for hexanal and heptanal were 1.87 and 0.78 nmol L−1, respectively. The average recoveries of urine samples of healthy humans ranged from 82.5% to 99.4% with the inter- and intra-day precisions (n = 6) less than 8.4%. Because of the excellent magnetic responsibility and high dispersibility of the MNPs, the proposed method was shown to be simple and rapid. Besides, this method possesses advantages such as low-cost, efficiency and good reproducibility.
Co-reporter:Hui Xu, Xiaoman Sun and Dandan Song
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 12) pp:NaN4167-4167
Publication Date(Web):2012/11/02
DOI:10.1039/C2AY25918D
In this study, a polypropylene sieve with porous network structure was coated with polydimethylsiloxane (PDMS) and used as extraction phase. Based on the PDMS-sieve, a rapid, simple and sensitive sorptive extraction method was established for analysis of five pyrethroid residues in tea samples. In the method, pyrethroids in a stirred solution were extracted on a PDMS-sieve, the analytes loaded on the sieve were then ultrasonically desorbed in ethyl acetate and analyzed by gas chromatography-mass spectrometer (GC-MS) with selected ion monitoring mode (SIM). The proposed method was optimized and validated, the matrix-matched calibration curves were performed at six concentration levels and good linear correlations (r) were obtained (r ≥ 0.9907) within the range of 0.001–0.1 μg mL−1. The detection limits (LODs) of five pesticides ranged from 0.8 ng g−1 to 19.6 ng g−1. Good repeatability was obtained with the inter- and intra-day relative standard deviation (RSDs) values lower than 10%. The method has been applied successfully to the determination of pyrethroids in six tea samples, and satisfactory recoveries ranging from 82% to 111% were obtained. The results indicated that the proposed method is suitable for trace analysis of pesticides residues in tea samples.
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