Nonaqueous capillary electrophoresis

Cherkaoui S, Veuthey JL. 2002. Nonaqueous capillary electrophoresis-electrospray-mass spectrometry for the analysis of fluoxetine and its related compounds. Electrophoresis 23 442. 

Marini, R. D., Servais, A.-C., Rozet, E., Chiap, P., Boulanger, B., Rudaz, S., Crommen, J., Hubert, P., and Fillet, M. (2006). Nonaqueous capillary electrophoresis method for the enantiomeric purity determination of 5-timolol using heptakis(2,3-di-0-methyl-6-0-sulfo)-p-cyclodextrin validation using the accuracy profile strategy and estimation of uncertainty. /. Chromatogr. A 1120(1—2), 102-111. 

Rodriguez-Flores, J., Berzas Nevado, J. J., Contento Salcedo, A. M., and Cabello Diaz, M. P. (2005). Nonaqueous capillary electrophoresis method for the analysis of gleevec and its main metabolite in human urine. J. Chromatogr. A 1068, 175-182. 

Jussila, M., Sinervo, K., Porras, S. P, and Riekkola, M. L. (2000). Modified liquid-junction interface for nonaqueous capillary electrophoresis-mass spectrometry. Electrophoresis 21, 3311—3317. 

Cherkaoui, S., Varesio, E., Christen, P., and Veuthey, J. L. (1998). Selectivity manipulation using nonaqueous capillary electrophoresis. Application to tropane alkaloids and amphetamine derivatives. Electrophoresis 19, 2900—2906. 

Bjornsdottir, I., and Hansen, S. H. (1995). Comparison of separation selectivity in aqueous and nonaqueous capillary electrophoresis./. Chromatogr. A 711, 313-322. 

Anderson, M. S., Lu, B., Abdel-Rehim, M., Blomberg, S., and Blomberg, L. G. (2004). Utility of nonaqueous capillary electrophoresis for the determination of lidocaine and its metabolites in human plasma a comparison of ultraviolet and mass spectrometric detection. Rapid Commun. Mass Spectrom. 18, 2612—2618. 

Matysik, F. M. (2002). Special aspects of detection methodology in nonaqueous capillary electrophoresis. Electrophoresis 23, 400—407. 

Yang, Q., Benson, L. M., Johnson, K. L., and Naylor, S. (1999). Analysis of lipophilic peptides and therapeutic drugs-on-line- nonaqueous capillary-electrophoresis mass-spectrometry. /. Biochem. Biophys. Methods 38, 103 — 121. 

Ahrer, W., and Buchberger, W. (1999). Determination of haloacetic acids by the combination of nonaqueous capillary-electrophoresis and mass-spectrometry. Fresenius J. Anal. Chem. 365, 604-609. 

Nonaqueous capillary electrophoresis is a new technique that matured over the last couple of years to complement the electrophoretic techniques performed under aqueous conditions. Consequently, it extends the applicability of CE to those analytes that are insoluble or only sparsely soluble in water, including several classes of pharmaceutical compounds and long-chain fatty acids, vitamins, and surfactants, to name only a few. 

The use of organic solvents in nonaqueous capillary electrophoresis not only increases the solubility of the solutes, but also allows one to control important characteristics of the separation. For instance, the solvent properties affect the acid-base behavior of the analytes on a wider scale than... 

The effect of an additive (Brij 35) on the mobilities of different porphyrins (photodynamic anticancer drugs) was studied in a nonaqueous capillary electrophoresis system based on a 1 1 complexation model (118). 

Miller, J. L., Khaledi, M. G., and Shea, D., Separation of polycyclic aromatic hydrocarbons by nonaqueous capillary electrophoresis using charge-transfer complexation with planar organic cations, Anal. Chem., 69,1223-1229,1997. 

Qi, S., Ding, L., Tian, K., Chen, X., and Hu, Z., Novel and simple nonaqueous capillary electrophoresis separation and determination bioactive diterpenes in Chinese herb, /. Pharm. Biomed. Anal., 40, 35-41, 2006. 

Vaher, M., Koel, M., and Kaljurand, M., Ionic liquids as electrolytes for nonaqueous capillary electrophoresis. Electrophoresis, 23, 426-430, 2002. 

Carabias-Martinez, R., E. Rodriquez-Gonzalo, J. Dominquez-Alvarez, and J. Hemandez-Mendez (2002). Comparative study of separation and determination of triazines by micellar electrokinetic capillary chromatography and nonaqueous capillary electrophoresis Application to residue analysis in natural waters. Electrophoresis, 23 494—501. 

Capillary electrophoresis (CE) coupled to MS has the advantage of high resolution and soft ionization for biomolecules, which may be used to differentiate post-translational modifications and variants of intact proteins and oligonucleotides. Different modes of CE (capillary zone electrophoresis, capillary isoelectric focusing, capillary electrochromatography, micellar electrokinetic chromatography, nonaqueous capillary electrophoresis) to MS as well as online preconcentration techniques (transient capillary isotachophoresis, solid-phase extraction, membrane preconcentration) are used to compensate for the restricted detection sensitivity of the CE methodology [77, 78]. 

Carter SJ et al (2001) Biomonitoring of urinary tamoxifen and its metabolites from breast cancer patients using nonaqueous capillary electrophoresis with electrospray mass spectrometry. Electrophoresis 22 2730-2736... 

Ma, H. et al. Hydrogen-bond effect and ion-pair association in the separation of neutral calix[4]pyrroles by nonaqueous capillary electrophoresis. J. Chromatogr. A. 2008,1188, 57-60. 

Peri-Okonny UL, Kenndler E, Stubbs RJ, Guzman NA. Characterization of pharmaceutical drugs by a modified nonaqueous capillary electrophoresis—mass spectrometry method. Electrophoresis 2003 24 ... 

Problems encountered with CE include poor solubility of fatty acids in aqueous solutions and the unavailability of sensitive modes for aliphatic acids. This is often counteracted by nonaqueous capillary electrophoresis (NACE) with indirect detection. NACE-1A (indirect absorbance) is a simple, sensitive, and effective technique for the determination of fatty acids using i-PrOH and 40% acetonitrile (as organic modifier) and HIQSA... 

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