LCGC Europe-02-01-2009

Using a fixed length-variant of the kinetic plot method, it is illustrated how an analysis that is performed near the optimal flow-rate of a given commercial column can, in many cases, be performed between 50–200% faster by switching to a longer column and operating it at a higher pressure - at least, if the available instrument pressure admits so. The present article aims to show that short columns are not always the best choice to get the fastest separation.

Some things never change.

The concept of the limit of detection (LOD) has been, and still is, one of the most controversial in analytical chemistry. The multiple definitions and calculation methods proposed have contributed to this situation. Although in the last years, several international organizations, such as ISO or IUPAC, have tried to reach a consensus in their definitions and have issued guidelines for the estimation of this important parameter in chemical analysis, the subject is still a matter of scientific debate. In this article, we try to clarify the definition and provide guidelines to estimate LOD in chromatographic methods of analysis.

Part 2 of this three-part series focuses on comparing operation and performance of the most well known mass spectrometers.

Digital Update

PITTCON 2009

Various modes of capillary electrochromatography (CEC) for the separation of enantiomers on immobilized cyclodextrin derivatives are described. The following techniques have been used: (i) open-tubular electrochromatography (o-CEC), (ii) packed electrochromatography (p-CEC) and (iii) monolithic electrochromatography (rod-CEC). Three different strategies to prepare enantioselective cyclodextrin-coated chiral monoliths are described. The advantages and disadvantages of the various methods are outlined.