نتایج جستجو برای: separation and preconcentration
تعداد نتایج: 16843802 فیلتر نتایج به سال:
asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...
We report on a microfabricated device for sample preconcentration and capillary electrophoresis (CE) separation in a glass microchip. The device allows highly efficient anion-selective preconcentration to be performed with a micro-nanomicrochannel structure. An integrated cross channel enables gate-injection of the preconcentrated sample into the analysis channel for CE separation. Sample preco...
all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...
A preconcentration/separation procedure is presented for the solid phase extractionof trace cadmium and lead ions as their 2-propylpiperidine-1-carbodithioate (PPCD) chelates inenvironmental samples on Nano Graphene, prior to cadmium and lead determinations by atomicabsorption spectrometry. The preconcentration procedure was optimized by using model solutionscontaining c...
attempts have been made to study the thermodynamic behavior of 1,3 butadiene purification columns with the aim of retrofitting those columns to more energy efficient separation schemes. 1,3 butadiene is purified in two columns in series through being separated from methyl acetylene and 1,2 butadiene in the first and second column respectively. comparisons have been made among different therm...
asymmetric polyethersulfone (pes) microfiltration flat sheet membranes were composed by the phase inversion method (pim) and were used as supports. composite membranes were fabricated by coating silicone rubber as selective layer. effect of different concentrations of pes and pdms and different solvent such as nmp, dmf and dms effects as pes solvents and support thickness and different coagulat...
We present a novel technique for coupling isotachophoretic preconcentration and electrophoretic separation using bidirectional isotachophoresis (ITP). Bidirectional ITP simultaneously sets up sharp ITP interfaces between relatively high- and low-mobility cations and high- and low-mobility anions. These two interfaces can migrate toward each other and be described as ion concentration shock wave...
spectrometric techniques for the analysis of trace lead have developed rapidly due to the increasing need for accurate measurements at extremely low levels of this element in diverse matrices. this review covers separation and preconcentration procedures, and considers the features of the application with several spectrometric techniques. the use of an appropriate sample handling technique is a...
An extensive search of published research and review articles indicates that enhancing the sensitivity and resolution of capillary electrophoresis (CE) is a very active area of interest. This review focuses on developments and applications in this field over several years, especially from 2009-present. It first reviews developments in the fields of online sample preconcentration and highly sens...
in this research, nanoporous silica (sba-15) was physically functionalized using2-(2-nitrobenzylideneamino) guanidine compound. this functionalized sba-15 was utilized as a new sorbentfor separation and preconcentration of some lanthanide ions. inductively coupled plasma optical emissionspectrometry (icp-oes) was used as a detection technique. the preconcentration factor of the method is 100and...
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