Tony Taylor is the technical director of Crawford Scientific and ChromAcademy. He comes from a pharmaceutical background and has many years research and development experience in small molecule analysis and bioanalysis using LC, GC, and hyphenated MS techniques. Taylor is actively involved in method development within the analytical services laboratory at Crawford Scientific and continues to research in LC-MS and GC-MS methods for structural characterization. As the technical director of the CHROMacademy, Taylor has spent the past 12 years as a trainer and developing online education materials in analytical chemistry techniques.
Why would one want to use a mobile phase containing 100% water? Usually to wash the analyte or old mobile phase from the column (stationary phase surface) or to help retain analytes which elute quickly using mobile phases containing only very small amounts of organic solvent (usually highly polar analytes).
Much has been written about column overload, however, I've seen many instances lately in which overload may not be instantly recognized, or causes problems that may not normally be attributed to overload. Therefore, I wanted to explain how to spot and deal with different types of overload situations.
When developing a separation, some fundamental choices need to be made on how we might achieve the separation we require - primarily the mode of chromatography used and the way in which we intend to control and optimise the retention and separation (selectivity) of analyte components.
Many troubleshooting investigations in chromatography often don?t lead to a single causal factor. Often, the reason for problems or lack of method robustness are related to many small ?contributory factors? and this is particularly true of the problems associated with sample introduction in capillary Gas Chromatography.