The Column - June 2009 - 18

The Column www.thecolumn.eu.com Meeting Review and Aurora (Denis Berger). Each vendor outlined the latest technology available and the unique features they offered. The afternoon session started off with something a little different, and somewhat more entertaining than is the norm for scientiﬁc meetings, with a mock courtroom being set up in the lecture room. Tom Lynch (RSC Chromatography and Electrophoresis Group chairman) asked all delegates (the jury for the session) to be upstanding to welcome the Honourable Justice Peter Myers to preside over the case, which stated that “SFC had no place in the portfolio of modern analytical and puriﬁcation techniques for Pharma.” Presenting for the prosecution was Dr Bob Boughﬂower (GSK, Harlow, UK) and for the defence Professsor Pat Sandra (University of Ghent, Belgium). Both parties Myers Credit: Peter were given timed slots to present their case for and against SFC using the topics of scope of the technique, super/subcritical and speed; scaling-up and cost and the technique’s limitations and opportunities. In the scope section, Dr Boughtﬂower argued that unlike HPLC, retention in SFC was unpredictable, rendering stationary phase selection difﬁcult and when compared with LC its overall versatility was limited. Professor Sandra countered the argument by citing the numerous examples where SFC yields favourable retention for analytes eluting in the void volume of HPLC. He suggested that the prosecutions argument was far too selective and that the comparison of SFC and HPLC was akin to comparing apples and pears! Professor Sandra suggested that the tool was one that should be considered alongside all of our other analytical techniques but that the research effort and education/understanding of SFC was limited, so it had not achieved the acceptance that other more mature techniques had. The debate continued with issues of supervs subcritical and speed with Dr Boughtﬂower arguing against SFC not actually being true to its name as the majority of applications were not supercritical and that some applications were actually working in the two-phase region resulting in noisy baselines and a lack of sensitivity. In terms of speed he admitted that SFC is fast — but that with the advent of sub-2 µm particles and higher pressures and temperatures HPLC was just as fast. Professor Sandra countered the argument by humorously suggesting that the fast HPLC chromatograms with asymmetrical peaks, shown by the prosecution to demonstrate speed, were ‘ugly’ and if produced by one of his research students might have resulted in their research project being abandoned! Professor Sandra also argued that the comparative examples given for sub-2 µm technology with HPLC versus conventional Credit: Peter Myers particle size SFC separations were invalid, and that like should be compared with like. The debate then went on to address scale-up and cost with Dr Boughtﬂower arguing that scale-up in SFC is costly especially for high grade CO2 and that even if using lower grade versions, the additional kit required to do on-line puriﬁcation is costly. If even larger scale supplies are required, then the infrastructure (dedicated tanks, tubing, location etc.) was also particularly inhibitive. Professor Sandra countered this argument by describing examples of gases being used around the world in laboratories for GC and how this argument had not prohibited the successful application of GC. Furthermore, he argued that the cost of acetonitrile used in the majority of HPLC applications (notwithstanding the current crisis) was signiﬁcantly higher and, therefore, this argument was also not robust. The debate concluded by both parties summing up the opportunities and limitations of SFC. Dr Boughtﬂower stated that SFC was a normal phase technique that was most effective in the ‘little and often’ prep mode, which suffers from being difﬁcult to optimize separations, achieve sensitivity and recoveries and, more importantly, is prohibitive with respect to cost. Professor Sandra summed up by concluding that the separation science community should not be concerned about the ‘name’ of SFC and whether it is sub- or supercritical because what is really important is that SFC is a separation technique with 18 1 9 Contents Tips & Tricks 2 13 Vosloo Rainville and Mather 6 17 News Meeting Review 8 20 Market Trends & Analysis Events & Contacts
The Column - June 2009

Table of Contents for the Digital Edition of The Column - June 2009
