نتایج جستجو برای: preconcentration

تعداد نتایج: 2262  

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...

Journal: :Analytical and bioanalytical chemistry 2011
Chung-Shu Wu Fu-Ken Liu Fu-Hsiang Ko

Nanoparticle-based material is a revolutionary scientific and engineering venture that will invariably impact the existing analytical separation and preconcentration for a variety of analytes. Nanoparticles can be regarded as a hybrid between small molecule and bulk material. A material on the nanoscale produces considerable changes on various properties, making them size- and shape-dependent. ...

2017
Lingyan Gong Wei Ouyang Zirui Li Jongyoon Han

Electrokinetic concentration devices based on the ion concentration polarization (ICP) phenomenon have drawn much attention due to their simple setup, high enrichment factor, and easy integration with many subsequent processes, such as separation, reaction, and extraction etc. Despite significant progress in the experimental research, fundamental understanding and detailed modeling of the preco...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2005
César Ricardo Teixeira Tarley Eduardo da Costa Figueiredo Geraldo Domingues Matos

The present paper describes the on-line coupling of a flow-injection system to a new technique, thermospray flame furnace-AAS (TS-FF-AAS), for the preconcentration and determination of copper in water samples. Copper was preconcentrated onto polyurethane foam (PUF) complexed with ammonium O,O-diethyldithiophosphate (DDTP), while elution was performed using 80% (v/v) ethanol. An experimental des...

2013
M. DEHGHANI MOHAMMAD ABADI M. CHAMSAZ

The widespread use of silver compounds and silvercontaining procedures in industry, medicine, jewellery, cloud seeding and in disinfection of drinking water has resulted in an increasing silver content in environmental samples. Silver impregnated filters are used in water disinfection, while silver concentrations up to 200 μg L are permitted for antimicrobial activities for human health. Silver...

2003
C. Bosch Ojeda F. Sánchez

A flow injection on-line sorption preconcentration system for the electrothermal atomic absorption spectrometric determination of platinum has been developed. The method employs on-line preconcentration of platinum on a column packed with silica gel functionalised with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide (DPTH-gel) placed in the autosampler arm. The modification of the autosampler...

2017
Maria Espina-Benitez Lilia Araujo Avismelsi Prieto Alberto Navalón José Luis Vílchez Paola Valera Ana Zambrano Vincent Dugas

A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromato...

Journal: :Journal of hazardous materials 2009
Amjad H El-Sheikh Jamal A Sweileh Maysoon I Saleh

The aim of this work is to develop a preconcentration procedure of Cd(2+), Zn(2+) and Cu(2+) in environmental waters using olive pomace (OP) prior to their determination by flame atomic absorption spectrometry (FAAS). Raw OP as preconcentrating sorbent was found to have low permeability towards the passed water samples and thus long time was needed. Even reducing the vacuum pressure caused cart...

2011
Sławomir Oszwałdowski Katarzyna Zawistowska-Gibuła Kenneth P. Roberts

In the present work, CdSe nanocrystals (NCs) synthesized with a trioctylphosphine surface passivation layer were modified using amphiphilic molecules to form a surface bilayer capable of providing stable NCs aqueous solutions. Such modified nanocrystals were used as a test solute in order to analyze new electrophoretic phenomena, by applying a micellar plug as a separation tool for discriminati...

2011
Vanessa N. Alves Simone S. O. Borges Waldomiro B. Neto Nívia M. M. Coelho

In this study, a method for the determination of low concentrations of lead in beer samples using solid-phase extraction with a flow injection analysis system and detection by flame atomic absorption spectrometry (FAAS) was developed. Moringa oleifera seeds were used as a biosorbent material. Chemical and flow variables of the online preconcentration system, such as sample pH, preconcentration ...

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