Mobile-phase practical considerations related

When choosing an adsorbent for a liquid chromatography separation, whether analytical, preparative or process scale, there are a number of practicalities which need to be considered. The type of packing material must be selected with due consideration to the type of molecule being separated size, shap hydrophobidty and electrostatic characteristics are all important as are the contaminants from which it is to be separated. None of the adsorbents used in liquid chromatography are completely inert in their behaviour towards the sample and mobile phase and therefore the physical and chemical characteristics of the adsorbent must also be related to the sample type for optimised separations with maximum throughput and colurrm lifetime. The required purity of the final product must be considered when devising a... 

Mobility of H-atoms in hydrogen oxide bronzes and related systems has excited considerable interest in view of their possible applications in e.g. catalysis and electrochromic electrodes for display devices. In practical materials the structure of the host oxide may be ill-defined and intercrystallite regions may contribute significantly to observed (bulk) mobilities. This article aims to present a consistent picture (derived from the published work of many scientists internationally) of the atomic level phenomena responsible for intracrystallite H-atom mobility in well-characterized single phases. The detailed characterization of such phases is discussed by Dickens Chippindale (Chapter 7). 

---