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2005年11月07日

【期刊论文】On-line sample-pre-treatment schemes for trace-level determinations of metals by coupling flow injection or sequential injection with ICP-MS

王建华, Jianhua Wang, Elo Harald Hansen

Trends in Analytical Chemistry, Vol. 22, No.11, 2003,-0001,():

-1年11月30日

摘要

Within the last decade, the first generation of flow injection (FI) has been supplemented by sequential injection (SI), also termed the second generation, and, recently, by the third generation, i.e., SI-Lab-on-Valve (SILOV). As apparent from the literature, FI and/or SI have become dominant as substitutes for labor-intensive, manual, sample-pre-treatment and/or solution-handling procedures prior to analyte detection by inductively coupled plasma mass spectrometry (ICP-MS). The present review presents and discusses the progress of the state of the art in implementing miniaturized FI/SI systems for on-line matrix separation and pre-concentration of trace levels of metals with detection by ICP-MS. It highlights some of the frequently applied on-line, sample-pre-treatment schemes, including solid phase extraction (SPE), on-wall molecular sorption and precipitate/(co)-precipitate retention using a polytetrafluoroethylene (PTFE) knotted reactor (KR), solvent extraction-back extraction and hydride/vapor generation. It also addresses a novel, robust approach, whereby the protocol of SI-LOV-bead injection (BI) on-line separation and pre-concentration of ultra-trace levels of metals by a renewable microcolumn is interfaced to ICP-MS, as conducted in the present authors' group. It discusses the future outlook in this field.

Flow injection (, FI), , Inductively coupled plasma mass spectrometry (, ICPMS), , Lab-on-Valve (, LOV), , Matrix removal, Pre-concentration, Separation, Sequential injection (, SI),

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2005年11月07日

【期刊论文】Sequential injection lab-on-valve: the third generation of flow injection analysis

王建华, Jianhua Wang, Elo Harald Hansen

Trends in Analytical Chemistry, Vol. 22, No.4, 2003,-0001,():

-1年11月30日

摘要

Termed the third generation of flow-injection analysis, sequential injection (SI)-lab-on-valve (LOV) has specific advantages and allows novel, unique applications-not least as a versatile front end to a variety of detection techniques. This review presents and discusses progress to date of the SI-LOV approach as well as its applications in the automation and the micro-miniaturization of on-line sample pre-treatment. Special emphasis is placed on using SI-LOV in conjunction with bead injection (BI) for on-line separation and pre-concentration of ultra-trace levels of metals by exploiting the renewable micro-column approach. With detection by ETAAS and ICP-MS, it is shown, as illustrated by recent results in the authors' laboratory, that this methodology eliminates the problems encountered in conventional on-line column pre-concentration systems, improves the overall operational efficiency and yields the robustness necessary for routine assays. Also discussed is the future potential of the SI-LOV approach as a front end to various analytical protocols.

Bead injection (, BI), , Electrothermal atomic absorption spectrometry (, ETAAS), , Inductively coupled plasma mass spectrometry (, ICP-MS), , Lab-on-valve (, LOV), , Renewable micro-column, Separation and pre-concentration, Sequential injection (, SI),

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2005年11月07日

【期刊论文】A DNA assay protocol in a lab-on-valve meso-fluidic system with detection by laser-induced fluorescence

王建华, Xuwei Chen, a Wenxing Wang b and Jianhua Wang*a

Analyst, 2005, 130, 1240-1244,-0001,():

-1年11月30日

摘要

An automatic protocol for in-situ assay of dsDNA is presented by employing a micro-sequential injection lab-on-valve meso-fluidic system, which facilitates precise fluidic handling at the 0.1-10ml level. Sub-nano-liter to a few micro-liters of DNA sample and ethidium bromide (EB) solutions were introduced into the meso-fluidic system, where EB binding onto DNA takes place and an intercalated DNA-EB adduct was formed, which was afterwards excited in the flow cell of the LOV by a 473nm laser beam, and the emitted fluorescence was monitored in-situ via optical fibers. The experimental variables, i.e., pH of the buffer solution, the concentration and volume of EB solution, the reaction time and the fluid flow rates, were investigated. By loading 600nl sample and 1.0ml EB solution, a linear calibration graph was obtained within 0.03-3.0mg ml21 (dsDNA), and a detection limit (3s) of 0.009mg ml21 was achieved, along with a sampling frequency of 60h21 and a precision of 1.9% at the 1.0mg ml21 level. The detection limit was further improved to 0.006mg ml21 by increasing the sample volume to 2.0ml. Plasmid DNA in E. Coli extraction and l-DNA/Hind III in four synthetic samples were assayed by using this procedure. For the plasmid DNA, a good agreement with the documented UV method was obtained, while spiking recoveries for the synthetic samples were 95.6-103.4%.

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2005年11月07日

【期刊论文】A spectrophotometric procedure for DNA assay with a microsequential injection lab-on-valve meso-fluidic system

王建华, Xuwei Chen, Jianhua Wang, Zhaolun Fang

Talanta 67(2005)227-232,-0001,():

-1年11月30日

摘要

A micro-sequential injection spectrophotometric procedure for DNA assay was developed based on the employment of a lab-on-valve (LOV) meso-fluidic analytical system. A small amount of crystal violet solution (10μl) was de-colored inside the flow cell of the LOV at the presence of 5μl λ-DNA/HindIII within a certain pH range, and the absorbance decrease of crystal violet solution at 591 nm was measured via optical fibers and was employed as the basis of quantification. A uni-variant approach was adopted for the optimization of experimental parameters, including buffer pH, concentration and volume of crystal violet solution, reaction time and sample/reagent loading flow rates. A linear calibration graph was obtained within 0.2-6.0μgml−1, along with a detection limit of 0.07μgml−1. The procedure was applied for the determination of λ-DNA/HindIII in synthetic samples in comparison with a documented procedure.

Sequential injection, Lab-on-valve, Meso-fluidic analytical system, Spectrophotometry, DNA assay

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  • 王建华 邀请

    东北大学,辽宁

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