Permanently Coated Columns

Takeuchi et al. [343] described an indirect photometric detection method for anions in micro high performance liquid chromatography. Micro anion exchange octadecylsilica columns permanently coated with the hydrophobic cetyltrimethylammonium ion (cetrimide) were used in the high performance liquid chromatography of chloride, nitrate... 

Connolly, D. and Pauli, B. Fast ion chromatography of common inorganic anions on a short ODS column permanently coated with didodecyldimethylammonium bromide. J. Chromatogr A. 2002, 953, 299-303. 

Several investigators have obtained good separations of anions on coated columns. Connolly and Pauli [18] obtained fast ion-chromatographic separation of common anions using a 3-cm silica Cig column permanently coated with DDAB. Short columns were found to have better chromatographic efficiency than longer columns. 

Permanently coated stationary phases were also used in the presence of an IPR in the eluent different from that used for the coverage. Incorporation of a non-ionic surfactant in the coating solution proved very useful for improving peak shape the underlying material in coated columns still participates in analyte retention [10]. 

Yoshikawa, K. et al. Talanta. Ion chromatographic determination of organic acids in food samples using a permanent coating graphite carhon column. 2007, 72, 305-309. 

In this section, detailed descriptions of typical procedures involving dynamic ion-exchange and permanently coated columns are given. 

Separation of lanthanides using permanently coated columns... 

D. Connoly D. Victory and B. Pauli, Rapid, low pressure and simultaneous ion chromatography of common inorganic anions and cations or short permanently coated monolithic columns,/. Sep. Sci., 27, 912, 2004. 

In 1993, Hu, Takeuchi and Haraguchi [5] described a technique in which anions and cations were separated simultaneously on a zwitterion stationary phase with pure water as the eluent. An octadecyl silica column acquired a semi-permanent coating when a solution of a zwitterionic surfactant was passed through the column. It was demonstrated that analyte cations and anions were eluted together. The ability to separate ions by ion chromatography with a mobile phase containing no chemicals whatsoever is an ideal situation for detection of the ionic analytes. 

The complex mixtures of methylated alditol acetates, often obtained after methylation analysis, cannot be adequately resolved on conventional packed GLC columns. The fractionation of large numbers of these derivatives now can be achieved using capillary columns (Geyer et al., 1982). It is unlikely that a single column can adequately resolve all the derivatives from the methylation analysis of plant cell walls (Lomax et al., 1985). A combination of different liquid phases and coating procedures, namely wall-coated (WCOT), support-coated (SCOT), and permanently bonded (BP) phases will be required (Geyer et al., 1982 Lomax et al., 1985). As an alternative to PMAA, partially ethylated alditol acetates may be used... 

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