Non-aqueous capillary electrophoresis NACE

Dedicated applications of capillary zone electrophoresis (CZE) coupled to MS are discussed, particularly in the field of drug analysis. Development of other capillary-based electrodriven separation techniques such as non-aqueous capillary electrophoresis (NACE), micellar electrokinetic chromatography (MEKC), and capillary electrochromatography (CEC) hyphenated with MS are also treated. The successful coupling of these electromigration schemes with MS detection provides an efficient and sensitive analytical tool for the separation, quantitation, and identification of numerous pharmaceutical, biological, therapeutic, and environmental compounds. 

The recent introduction of non-aqueous media extends the applicability of CE. Different selectivity, enhanced efficiency, reduced analysis time, lower Joule heating, and better solubility or stability of some compounds in organic solvent than in water are the main reasons for the success of non-aqueous capillary electrophoresis (NACE). Several solvent properties must be considered in selecting the appropriate separation medium (see Chapter 2) dielectric constant, viscosity, dissociation constant, polarity, autoprotolysis constant, electrical conductivity, volatility, and solvation ability. Commonly used solvents in NACE separations include acetonitrile (ACN) short-chain alcohols such as methanol (MeOH), ethanol (EtOH), isopropanol (i-PrOH) amides [formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA)] and dimethylsulfoxide (DMSO). Since NACE—UV may present a lack of sensitivity due to the strong UV absorbance of some solvents at low wavelengths (e.g., formamides), the on-line coupling of NACE... 

The interaction of the polymeric analyte molecules (charged or uncharged) with the polymeric sieving media (uncharged or charged) is a general and principal method for analytical separation of water-soluble polymers. Transfer of this technique to water-insoluble polymers by applying the technique of non-aqueous capillary electrophoresis (NACE) seems feasible. 

Madej et al. [76] used a non-aqueous capillary electrophoresis (NACE) method for the screening and quantification of seven phenothiazine derivatives in blood. The optimal medium for dissolving the examined blood extracts was tested. The linear dynamic ranges were between 0.25 and 4.00 xg/mL (correlation coefficients higher than 0.996), the RSD values going from 1.21 to 9.15%, according to the compound. The detection limits were 0.08 xg/mL for promazine and 0.15 pg/mL for the rest of the drugs under study. Finally, the proposed method was applied to two forensic blood samples, and concentrations of the examined phenothiazines determined by the HPLC and NACE methods were found to be comparable. 

Galeano-Diaz, T., Acedo-Valenzuela, M. I. Silva-Rodriguez, A. (2012). Determination of tocopherols in vegetable oil samples by non-aqueous capillary electrophoresis (NACE) with fluorimetric detection. J. Food Comp. Anal, 25, 24-30. 

Figure 3.33 Electropherogram (A) and chromatogram (B) corresponding to a fortified drinking water sample analysed with both SPE with NACE and SPE with HPLC methods (Eive hundred milliliters aliquot of sample fortified at 0.50 ig/L for each triazine and polar metabolite. Reprinted from Journal of Chromatography A. Carabias-Martinez, R, et ai, Comparison of a non-aqueous capillary electrophoresis method with high performance liquid chromatography for the determination of herbicides and metabolites in water samples, 22(l-2), 194-201, Copyright 2006 with permission from Eisevied ).

NACE Non-Aqueous Capillary Electrophoresis SFC Supercritical Fluid Chromatography... 

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