Capillary zone electrophoresis current

DGE a AC AMS APCI API AP-MALDI APPI ASAP BIRD c CAD CE CF CF-FAB Cl CID cw CZE Da DAPCI DART DC DE DESI DIOS DTIMS EC ECD El ELDI EM ESI ETD eV f FAB FAIMS FD FI FT FTICR two-dimensional gel electrophoresis atto, 10 18 alternating current accelerator mass spectrometry atmospheric pressure chemical ionization atmospheric pressure ionization atmospheric pressure matrix-assisted laser desorption/ionization atmospheric pressure photoionization atmospheric-pressure solids analysis probe blackbody infrared radiative dissociation centi, 10-2 collision-activated dissociation capillary electrophoresis continuous flow continuous flow fast atom bombardment chemical ionization collision-induced dissociation continuous wave capillary zone electrophoresis dalton desorption atmospheric pressure chemical ionization direct analysis in real time direct current delayed extraction desorption electrospray ionization desorption/ionization on silicon drift tube ion mobility spectrometry electrochromatography electron capture dissociation electron ionization electrospray-assisted laser desorption/ionization electron multiplier electrospray ionization electron transfer dissociation electron volt femto, 1CT15 fast atom bombardment field asymmetric waveform ion mobility spectrometry field desorption field ionization Fourier transform Fourier transform ion cyclotron resonance... 

Currently, there are five major modes of operation of CE capillary zone electrophoresis (CZE), also referred to as free solution or free flow capillary electrophoresis micellar electrokinetic chromatography (MEKC) capillary gel electrophoresis (CGE) capillary isoelectric focusing (CIEF) and capillary isotachophoresis (CITP). Of these, the most commonly utilized capillary techniques are CZE and MEKC (Rabel and Stobaugh 1993 Issaq 1999 Smyth and McClean 1998). 

Of the inorganic anions which are currently monitored chloride, sulphate, and in many instances also nitrate, are considered anionic macroconstituents. These are often accompanied by nitrite, fluoride and phosphate present in samples at 102-105-fold lower concentrations. Such a concentration span probably cannot be covered by capillary zone electrophoresis. 

Bocek and his group [2] developed a method for controlling the composition of the operational electrolyte directly in the separation capillary in isota-chophoresis (ITP) and capillary zone electrophoresis (CZE). The method is based on feeding the capillary with two different ionic species from two separate electrode chambers by simultaneous electromigration. The composition and pH of the electrolyte in the separation capillary is thus controlled by setting the ratio of two electric currents. This procedure can be used, in... 

Many important developments have been made during the last few years but are not yet commercially available. Specifically, there is an active interest in electrospray and continuous flow fast atom bombardment (FAB) for peptides. Applications using supercritical fluid chromatography (SFC) in combination with MB1 and DLI have been slow but continue to attract interest. The current work in capillary zone electrophoresis (with... 

Capillary zone electrophoresis (CZE), with direct or indirect photometry and conductivity has become popular in wine analysis. Very little, or sometimes no sample preparation is needed and short analysis times are also apparent advantages of CE and CZE in the analysis of wine. Capillary isotachophoresis (ITP), with conductivity, thermometric, and UV absorption detection, is suitable for the separation of various anionic constituents (organic acids and inorganic anions), currently occurring in wines (Masar et al., 2001). 

Several modes of CE have been described in the literature over past decade [6, 7], The most common are open tubular or capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), microemulsion elec-trokinetic chromatography (MEEKC), capillary electrochromatograpy (CEC), capillary gel electrophoresis, capillary isoelectric focusing and capillary iso-tachophoresis. Three recent reviews by Watzig [113], Tagliaro etal. [114] and Riekkola etal. [115] summarise the current method development options available to manipulate selectivity. In pharmaceutical analysis, CZE, MEKC, MEEKC and CEC are commonly used. 

Dyes, and espedally azo dyes, compounds of environmental concern because of their carcinogenic potential, were studied with TSP-LC-MS [28, 201]. An overview presented current methodologies for determining sulfonated azo dyes in environmental waters using TSP [200]. Results obtained by LC-MS and capillary zone electrophoresis (CZE) MS, coupled with TSP-, APCI-, and ESI interface were discussed [43]. 

Huang, X.H., Gordon, M.J., and Zare, R.N., Current-monitoring method for measuring the electroosmotic flow-rate in capillary zone electrophoresis. Ana/. Chem., 1988, 60 1837-1838. 

An entirely different concept in analytical separations is provided by capillary electrophoresis (CE) in which the flow of liquid is generated by electro-osmotic flow (EOF) driven by an external electric field. The major advantage of this approach is the essentiaUy flat plug flow profile that leads to intrinsically more narrow elution peaks than the parabolic flow profiles characteristic of pressure-driven viscous flows. In capillary zone electrophoresis (CZE) separation is achieved by superimposing the different electrophoretic mobihties of the solutes on to the EOF. In electrochromatography the separation is achieved as in packed column HPLC but using an EOF to generate flow of the mobile phase past the stationary phase particles. The importance of these EOF-based techniques is their application to miniaturized devices, lah-on-a-chip or micro total analysis systems. Such devices that can be directly interfaced to a mass spectrometer via an ESI source are currently under intense development. 

Huang X, Gordon Ml, Zare RN (1988) Current-Monitoring Method for Measuring the Electro-osmotic Row Rate in Capillary Zone Electrophoresis. Anal Chem 60 1837-1838... 

Capillary zone electrophoresis (CE) is a relatively new analytical method currently under investigation for use in research and control laboratories for the analysis of ionic forms of vitamins. Micellar electrokinetic capillary chromatography (MECC) is a modification of CE which allows the separation of both neutral and ionic forms using buffers with micellar additives. Both methods have been used to separate water-soluble vitamins but very rarely pantothenic acid, which has only been analyzed by this technique in model mixtures and pharmaceuticals. 

---