Gradient ion chromatography

Dabek-Zlotorzynska, E. and Dlouhy, J. F., Simultaneous determination of alkali, alkaline-earth metal cations and ammonium ion environmental samples by gradient ion chromatography, /. Chromatogr., 638, 35, 1993. 

Riordan, C.O. et al. Double gradient ion chromatography using short monolithic columns modified with a long chained zwitterionic carhoxybetaine surfactant. J. Chromatogr. A. 2006, 1109, 111-119. 

D. T. Gjerde, D. J. Cox, P. Jandik and J. B. Li, Determination of analytes at extreme concentration ratios by gradient ion chromatography with solid-phase reaction detection, J. Chromatogr., 546, 151,1991. 

Monolithic columns are applied in low- and medium-pressure ion chromatography, ultrafast ion chromatography, capillary chromatography, flow gradients, and double-gradient ion chromatography, and, also, multi-column/multidimensional ion chromatography. Monolithic columns are considered, by many, to be a... 

Boyles, S. 1992. Method for the analysis of inorganic and organic acid anions in all phases of beer production using gradient ion chromatography./. ASBC 50 61-63. 

Finally, ion chromatography can be used to determine the a-sulfo fatty acid esters. The chromatographic column is a nonpolar poly sty rene/divinylbenzene column and the ion pair reagent is 0.005 M ammonia. In order to reduce the elution time, acetonitrile is added as a modifier with increasing concentration. This gradient technique makes it possible to separate simultaneously ester sulfonates and disalts by chain length. Determination is achieved by standards with defined chain length [107]. 

Figure 4.21 Exploded view of a nlcroaeBbrane suppressor and gradient elution separation of a aixture of inorgemic and organic anions by ion chromatography employing conductivity detection with a mlcromembrane suppressor.

Van Moorleghem C, Six L, Degryse F, Smolders E, Merckx R. Effect of organic P forms and P present in inorganic colloids on the determination of dissolved P in environmental samples by the diffusive gradient in thin films technique, ion chromatography, and colorimetry. Anal. Chem. 2011 83 5317-5323. 

This chapter reviews the underlying principles of ion chromatography and its application in pharmaceutical analysis. It provides an overview of eluent systems, applications of gradients, electrolytic eluent generation, suppressors, and stationary phases. Applications of ion chromatography to the confirmation of counter ions, active ingredient analysis, competitive analysis and development work are discussed. 

Ion chromatography has become an essential tool of the pharmaceutical analytical chemist. The high sensitivity of the technique, coupled with the wide dynamic operating range made possible with modern high-capacity stationary phases makes it ideal for the analysis of ions in pharmaceutical applications. The combination of gradients and suppressed conductivity detection provides a powerful screening... 

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