The first microelectromechanical-system normally closed electrothermal valve constructed using Parylene C is described, which enables both low power (in milliwatts) and rapid operation (in milliseconds). This low-power valve is well suited for applications in wirelessly controlled implantable drug-delivery systems. The simple design was analyzed using both theory and modeling and then characterized in benchtop experiments. Operation in air (constant current) and water (current ramping) was demonstrated. Valve-opening powers of 22 mW in air and 33 mW in water were obtained. Following integration of the valve with catheters, our valve was applied in a wirelessly operated microbolus infusion pump, and the in vivo functionality for the appropriateness of use of this pump for future brain mapping applications in small animals was demonstrated.
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http://dx.doi.org/10.1109/JMEMS.2009.2031689 | DOI Listing |
Biol Trace Elem Res
May 2018
Research Center for Environmental Determinants of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran.
In this paper, a new extraction method based on countercurrent liquid-liquid microextraction (CLLME) has been developed for the extraction and preconcentration of inorganic arsenic (iAs) in plasma and urine samples prior to their analysis by electrothermal atomic absorption spectrometry (ETAAS). In this method, firstly, 5 ml of water is added to the extraction vessel. Then 30.
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June 2016
Department of Analytical Chemistry, Faculty of Sciences, University of Málaga, Campus de Teatinos, 29071 Málaga, Spain.
A new chelating sorbent which employs magnetic nanoparticles (MNPs) functionalized with 1,5-bis(di-2-pyridil)methylene thiocarbohydrazide (DPTH-MNPs) was synthetized and characterized. The aim of the synthesis of this material was to develop fast and simple methods for analysis of trace amounts of metal ions present in biological and environmental samples combining on-line magnetic solid phase microextraction (MSPME) with atomic spectrometry. The MNPs' magnetic core allows overcoming the backpressure problems that usually happen in SPME methods with NPs thanks to the possibility of immobilizing the MNPs by applying an external magnetic field.
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November 2014
Department of Analytical Chemistry, Faculty of Sciences, University of Málaga, Campus de Teatinos, 29071 Málaga, Spain.
A simple, sensitive, low-cost and rapid flow injection (FI) on-line sorption preconcentration/hydride generation system has been synchronously coupled to an electrothermal atomic absorption spectrometer (ETAAS) for the determination of trace amounts of Sb in aqueous environmental samples (river and sea water samples). The system is based on retention of the analyte onto a micro-column filled with a novel mesoporous silica functionalised with [1,5 bis(di-2-pyridyl) methylene] thiocarbohydrazide placed in the injection valve of the FI manifold. The adsorption capacity of the resin for Sb was found to be 160.
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November 2013
Institute of Analytical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinskeho 9, 812 37 Bratislava, Slovakia. Electronic address:
In this work the possibility of determination of selenium in water samples was studied by on-line coupling of electrochemical pre-concentration flow through unit and GFAAS. The pre-concentration unit was created from a commercial electrochemical flow through analyser EcaFlow (Istran Ltd.) and a special two-electrode electrochemical flow through cell.
View Article and Find Full Text PDFAnal Chim Acta
July 2013
Laboratory of Analytical Chemistry, Department of Chemistry, Faculty of Science, Aristotle University, Thessaloniki, Greece.
The use of magnetic materials in solid phase extraction has received considerable attention in recent years taking into account many advantages arising from the inherent characteristics of magnetic particles. Magnetic solid phase extraction (MSPE) methodology overcomes problems such as column packing and phase separation, which can be easily performed by applying an external magnetic field. The use of magnetic particles in automatic systems is growing over the last few years making the on-line operation of MSPE a promising technique in the frame of green chemistry.
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