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volume of the analyte (essentially desolvation of the molecule making it more hydrophobic).


Dr David McCalley (University of the West of England, Bristol, UK) gave a moving eulogy to Uwe Neue and in his talk on “Are superficially porous particles a viable


alternative to sub-2 µm particles for fast, efficient analysis in HPLC?” frequently cross- referenced to his discussions on separation science with Uwe. He discussed the effect of increasing flow (and pressure as a consequence) on the retention of analytes. For neutral molecules a 2-12% increase in the retention factor (k) was observed when the pressure increased by 500 bar. Charged basic analytes (e.g. nortriptyline) exhibited a 35- 51% increase in k with the same pressure change. The greater effect on the charged analytes is thought to be due to the more extensive hydration of these analytes compared to neutral molecules. This observation may have an impact when moving from HPLC to UHPLC methods. In the second part of his presentation he discussed the significant loss in efficiency when 0.21 and 0.46 mm i.d. columns are used on standard HPLC instruments compared to UHPLC instruments. For a 0.46 mm id column an efficiency loss of around 6% was noted, but for a 0.21 mm column, this was nearer 20%. This was due to extra column band broadening effects form the HPLC system. He rounded out his presentation by discussing fused core particles and demonstrated that 0.21 mm i.d. Kinetex columns had a worse hmin than 0.46


mm columns. He also demonstrated that Kinetex columns could be easily overloaded at sample concentrations as low as 1000 ppm. Details of this work may be found in: D.V. McCalley et al J. Chromatogr. A (2008) 1209 95; D.V. McCalley J. Chromatogr. A (2010) 1217 276; D.V. McCalley et al J. Chromatogr. A (2007) 1169 125; D.V. McCalley J. Chromatogr. A (2011) 1218 2887


The session before lunch was given over to vendor presentations. Dr David Keay (Dynamic Extractions, UK) , “Maximising both purity and recovery in preparative liquid chromatography” discussed high performance counter current chromatography (HPCCC). The technique can be thought of performing multiple, high- speed liquid-liquid extractions where the aim is to separate compounds by varying the selectivity of the liquid mobile and stationary phases rather than efficiency. Dr Ken Cook (Dionex, UK) presented in his usual lively style on “Automated, High Resolution Therapeutic Protein Analysis” , inevitably touching on ion-exchange separations, an area of some expertise for Dionex. Simon Lambert (ARC Sciences, UK) discussed Scherzo multi-mode LC phases both extolling the virtues of multi-mode operation and highlighting the impressively high


efficiency e.g. Imtakt C18 (3 µm) – 200,000 N/m. In the final talk before lunch Stephan Altmaier (Merck Millipore, Germany) described the latest developments in his company’s work on monolithic silica HPLC columns (Chromolith 2nd generation and


Chromolith capillaries).


Suitably invigorated by lunch, networking, viewing exhibitor stands and, not least, the fascinating ChromSoc AGM, delegates settled down to the final session which consisted of presentations by speakers from Discovery phase scientists from major UK pharma companies i.e. GSK and Novartis on the theme of purification strategies. Dr Bob Boughtflower (GSK, UK) discussed GSK’s long-standing collaboration with Shimadzu to develop an automated purification system where crude Discovery compound are input and >99% pure material is output in a short time period. This had moved on considerably since Bob first described this initiative at a ChromSoc Prep meeting some years ago. It is now well established and has led to some useful developments in retentive stationary phases. Dr Jenny Kingston (Novartis, UK) discussed Novartis (Horsham’s) strategies to support their medicinal chemists. This includes principally RPLC, SFC and HPCCC platforms. In their experience the Phenomenex diol HILIC phase performs better than ethylpyridine phases, but the latter does offer complementary selectivity. In another contribution from GSK, the use of counter-current chromatography in Development as opposed to Discovery was described.


In his closing address ChromSoc President Alan Handley reflected upon yet another highly successful Spring Symposium held at a major UK pharmaceutical R&D site. Let’s hope that it is not the last!


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