A new flow injection on-line adsorption preconcentration system adapted to flame atomic absorption spectrometry (FAAS) for copper determination at the g l level was developed. Polytetrafluoroethylene (PTFE) turnings packed in a mini-column were used as sorbent material. The copper ammonium pyrrolidine dithiocarbamate (APDC) complex was sorbed on the PTFE turnings, from which it could be eluted ...

Microchip electrophoresis (MCE) has been advanced remarkably by the applications of several separation modes and the integration with several chemical operations on a single planer substrate. MCE shows superior analytical performance, e.g., high-speed analysis, high resolution, low consumption of reagents, and so on, whereas low-concentration sensitivity is still one of the major problems. To o...

A flow injection photometric method for the sequential determination of zinc and copper in mixtures was developed based on the variation of the stability of the chromogenic complexes between the analytes and the reagent zincon with pH. At pH 5.0 only the Cu-zincon complex exists, whereas at pH 9.0 the copper and zinc chelates co-exist. A three-channel manifold was implemented containing two alt...

a simple method has been developed for the preconcentration of copper(ii) based on the adsorption of its modified nano polyacrylonitrile fiber. modified nano polyacrylonitrile fiber (panf) was prepared by adding of acrylic fibers to msethanolamine (mma) with different concentration solutions. the stability of a chemically modified nano polyacrylonitrile fiber especially in concentrated hydrochl...

Field-enhanced sample stacking, field-enhanced sample injection as well as electrokinetic supercharging have been successfully integrated in carrier ampholyte-based capillary electrophoresis. Through the analysis of different test sample mixtures, it has been shown that the carrier ampholyte-based background electrolytes, in spite of their very low conductivity, allow efficient online preconcen...

In this paper, we reported a simple, disposable PDMS micro/nanofluidic preconcentration chip for in vitro concentration-enhanced cell kinase assays. Utilizing the preconcentration (electrokinetic trapping) directly from cell lysate (1 mM ATP) samples, we could achieve at least a 25-fold increase in reaction velocity and 65-fold enhancement in sensitivity. In addition, we shorten the assay time ...

In this work, using benzo(a)pyrene (BaP) as marker, the analytical merits of on-line flow-injection cloud-point extraction (FI CPE), including preconcentration factor, extraction efficiency, sample throughput, and analysis time were evaluated by use of peroxyoxalate chemiluminescence (CL) detection. Moreover, by detailed discussion of several preconcentration conditions for traditional and on-l...

Solid phase extraction using a mini cartridge packed with 22 mg of chelate resin immobilizing carboxymethylated pentaethylenehexamine was successfully utilized for separation/preconcentration of cadmium in water samples prior to liquid electrode plasma atomic emission spectrometric (LEP-AES) determination. The combined method with the extraction and LEP-AES was applicable to the determination o...

a novel, simple, sensitive and effective method has been developed for preconcentration of hg(ii) on nano-fe3o4-dop-ed solid-phase extraction adsorbent. in this paper, dioctyl phthalate (dop) was used to encapsulate nano-fe3o4 and produce a nano-fe3o4-dop sorbent based new sorbent was prepared. this was treated with ethylenediamine (ed) in another solvent-free procedure for the formation of a n...

Microchip electrophoresis (ME) has emerged as a promising tool for rapid analysis of various sample types and it is one the most important modules miniaturized total systems. Electrokinetic effects provide both efficient transport separation components in microfluidic channels. Moreover, miniaturization devices drastically reduces reagent consumption, significantly decreases time, allows easier...