The potential of integration of functions in microfluidic chips is demonstrated by implementing on-chip preconcentration of proteins prior to on-chip protein sizing by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Two polymeric elements-a thin (approximately 50 microm) size exclusion membrane for preconcentration and a longer (approximately cm) porous monolith for protei...

The preconcentration of Hg through MDSPE and cold vapor (CV) resulted in an excellent LOD.

the present article reports on the application of modified organo nanoclay as a green, easily prepared and stable solid sorbent for the preconcentration of trace cobalt ion in aqueous solution. the organo nanoclay was modified by adsorption of 5-(4-dimethyl amino-benzylidene) rhodanin reagent onto it. the sorption of co2+ ions was quantitative in the ph range of 7.0 to 8.5, whereas quantitative...

absorption spectrometry was developed. The performance of retain transition metal ions. After the sample loading step, the the on-line preconcentration system was tested by determining metal ions are stripped from the column with a suitable eluent Cu and Mo in sea-water. Calibration graphs constructed from and directly injected into the nebulizer of a flame atomic the preconcentration of standa...

A rapid separation and preconcentration method was developed for the determination of trace metals Cu, Zn, Cd, and Pb in seawater using a minicolumn packed with thiol cotton fiber (TCF) coupled with inductively coupled plasma mass spectrometry (ICP-MS). Preconcentration parameters, such as seawater sample volume and flow rate and eluent hydrochloric acid concentration, volume and flow rate, wer...

Multi-walled carbon nanotube was oxidized with various oxidizing agents (nitric acid, hydrogen peroxide and ammonium persulphate) to produce multi-walled carbon nanotubes of various surface properties. The oxidized sorbents were used for the preconcentration of some metals (Mn, Pb, Cu, Cd, Zn) from environmental waters prior to their determination by flame atomic absorption spectroscopy. The be...

A new modified silica gel doped with 5-(4-dimethylaminobenzylidene)-rhodanine was prepared for separation, preconcentration and determination of silver ion by atomic absorption spectrometry. This new modified silica gel was used as an effective adsorbent for the solid phase extraction of Ag(+) from aqueous solutions. The variables that influence the adsorption/desorption of trace levels of Ag(+...

Flow-injection manifolds are described which allow the preconcentration of lead for flame atomic absorption determinations, using columns contained within the sample loop of an injection valve. An interface was designed which allowed the valves and pump in the system to be controlled by an autosampler which enabled precise timing of preconcentration and elution steps. The effects of sample flow...

A method integrating a long waveguide capillary cell with a preconcentration resin in a multi-syringe flow injection analysis (MSFIA) system for iron determination in waters was developed. The determination of iron is based on a colorimetric reaction and two reagents were tested, ferrozine and ammonium thiocyanate. A liquid waveguide capillary cell (1.0 m pathlength, 550 μm i.d. and 250 μL inte...

An electrokinetic trapping (EKT)-based nanofluidic preconcentration device with the capability of label-free monitoring trapped biomolecules through real-time dual-loop electric current measurement was demonstrated. Universal current-voltage (I-V) curves of EKT-based preconcentration devices, consisting of two microchannels connected by ion-selective channels, are presented for functional valid...