A Path to Greater Productivity in HPLC

The options facing the chromatographer have multiplied dramatically over the past few years. UHPLC, short fast columns, micro-bore, etc are all possible directions in which to move from the conventional HPLC column. Factor in the need to scale up for semi preparative or preparative use and the options increase again. In order to make the most cost effective choice, the whole process should be considered to determine the requirements to move from the current position to the required goal. All the available options need to be taken into account to reach the desired chromatographic level in the most cost effective way. The variables of
column length, internal diameter, flow rate, particle size and LC system availability should be considered along with temperature and column media options to optimise selectivity and reduce run time. There is a big difference between a 25cm x 4.6mm C18 column run isocratically on a standard HPLC system and a 2cm x 1mm column packed with sub 2μm specialist media run on a UHPLC column with a ballistic gradient or using 10μm media in a 50mm id preparative column. This article will point the way to the best and most cost effective path to greater productivity in HPLC for an individual analyst or group.

INTRODUCTION
In today’s busy world there are many challenges facing chromatographers who are asked to do more with less, and we need to rise to this challenge. The need for greater productivity leads us to look at faster analyses. The analysis of ever more complex samples leads to the need for greater resolution, and to be more cost effective leads us to reduce costs and spending without compromising quality or reproducibility. We need to look for products or protocols which will produce better results in less time with less cost and, if required, be capable of scaling up to the preparative level.

If we look at our requirements in chromatographic terms, there is often a need to maintain or improve the chromatogram fingerprint, to maintain specified or satisfactory peak resolution and to live within the pressure confines of the HPLC system. We may also need to increase the number of analyses per day or reduce work time, and maybe process more preparative samples. Finally, we need to avoid the need for method development when transitioning between scales and live within the confines of the budget.

Awareness of potential future requirements often dictates our best course of action. Will there be a future prep requirement? Will we need rapid on-line analysis? Will we need UHPLC for very high efficiency impurity profiles and so on?

Different column lengths, ids, flow rates, particle size, mobile phases, temperature, media and equipment need to be considered to make the best choice.