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.
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.
Of late we have been running a series called 'Lock and Leave', which serves as a reminder to pay attention to those instrument parameters which are often overlooked - you know the type of thing ? 'that's the best value for this system?, 'we always set to that value' and 'I have no idea what that does' ? it's always at that value'.
Surrogates, Internal Standards, Isotopically labelled Standards, External Standards, Calibrants, QC Samples etc. etc. - our working lives are littered with checks to ensure that our instruments are giving us the correct results. And rightly so. But do we always use these checks correctly? Do we know what we are checking and why? Indeed, do we know how to design methods/procedures which employ a valid checking regime, often referred to as a Quality System? Let's find out.
There has been much focus within the industry of late on ways of improving the way in which HPLC method development is carried out - which has led to a more widespread adoption of modelling and optimisation software combined with dedicated method development platforms from the major instrument vendors.