17
Vendor presentations were given by Dr David Keay (Dynamic Extractions), on ‘Maximising both purity and recovery in preparative liquid chromatography’, in which he 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.
Ken Cook (Dionex, UK) then discussed ‘Automated, High Resolution Therapeutic Protein Analysis’.
Simon Lambert (ARC Sciences) presented ‘Scherzo Multi-mode phase’, endorsing the blended phase possessing reversed-phase and normal phase together with anion and cation exchange capabilities. He also highlights impressive column efficiencies gained from the Sherzo phases, generating plate counts of as high as 200,000 N/m for the 3 micron Imtakt C18 material.
Dr Stephan Altmaier (Merck Millipore, Germany) discussed ‘Development of new monoliths silica HPLC columns – Chromolith 2nd generation and Chromolith capillaries’.
L to R: Speakers McCalley, Lindner and (seated) ChromSoc Vice-President, Paul Ferguson
required, which is achieved by decreasing the column i.d. James also reported on the effects of column wall thickness on frictional heating and heat dissipation from the column using 0.084” (standard) compared to thinner 0.026” steel column wall thickness. On reducing the thickness of the stainless steel tubing, an increase in retention was observed for some molecules with increasing temperature, attributed to a change in the partial molar volume of the analyte.
The session finale was presented by David McCalley, who worked extensively with Uwe over recent years, and gave his presentation on ‘Are superficially porous particles a viable alternative to sub-2 micron particles for fast efficient analysis of HPLC?’ Here he investigated the effects of pressure from increasing flow rate on the retention of analytes. For neutral molecules, a relatively small (2-12%) increase in retention factor was observed when the pressure increased by 500 bar, whereas for charged, basic analytes (e.g. nortryptyline) a much more significant effect (35-51%) increase was exhibited. This phenomenon is thought to be due to the more extensive hydration of these charged analytes compared to neutral molecules and may have an important influence when transferring methods from HPLC to UHPLC. In the second part of his presentation he discussed the significant loss in efficiency for both 0.46 cm i.d. (6%) and 0.21 cm i.d. (20%) when transferring methods from standard HPLC to UHPLC instrumentation due to extra system volume. Also discussed where fused-core particles with a particular emphasis on their loading behaviour, readily seen with ionisable compounds. He demonstrated that the capacity of shell particles was found to be around 60% lower than fully porous particles.
Symposium dinner was notable for good attendance of student delegates
Lunch came with an invitation to view the Open Access lab by Brian Everatt, which proved to be highly popular. Following on, the final session of the symposium was based on Purification Strategies and began with Bob Boughtflower of GSK presenting ‘Crude.2.Pure’ – A comprehensive, automated process for purifying compounds and recovering them as dry, weighable solids. His novel approach to purifying collected fractions is a result of a long-standing collaboration between GSK and Shimadzu, where crude discovery compounds are input and high purity material (98-99%) is output in a weighable, solid form. The system permits generic trapping and total recovery of sample free from solution and interfering additives in a short time.
Dr Jenny Kingston from Novartis continued with ‘Purification strategies to aid Medicinal Chemists’, discussing the use of orthogonal chromatographic platforms, including RPLC, SFC and HPCCC, for the generic separation and isolation of medicinal chemistry compounds.
Natalie Doullet, also of GSK, closed the scientific programme with her presentation on the ‘Potential for the Application of Counter Current Chromatography in Chemical Development’. HPCCC technologies and applications were discussed arising from the TSB/STEP Project, collaboration between Pfizer, GSK, Brunel University and Dynamic Extractions.
Post-dinner the chromatographic conversations flowed into the night The closing address was delivered by John Reilly, Norvartis.
Fast Yet Sensitive HPLC Analysis of N-Methylcarbamate Pesticides
Dionex is pleased to announce an improved method for the determination of carbamates in rice, potato, and corn (maize) as specified in AOAC Method 2007.01 and European Union standard EN 15662, 2008. Application Note 272: Faster Yet Sensitive Determination of N-Methylcarbamates in Rice, Potato, and Corn by HPLC demonstrates accurate results using this new application on an UltiMate® fluorescence detector.
3000 high-performance liquid chromatography (HPLC) system with an Acclaim® Carbamate column and detection performed using an FLD-3400RS
The N-methylcarbamates and the N-methylcarbamoximes are among the most widely used pesticides in agriculture. Because these pesticides may create health problems - including issues impacting the central nervous and reproductive systems - concerns over the presence of carbamate residues in water, crops, and food products have promoted increased awareness and testing for these
carbamate pesticides and related compounds in raw surface water using EPA Method 531.2.
compounds. This application provides detection in crops of the same pesticides specified in U.S. EPA guidelines for monitoring the presence of Circle no. 42
Interested in publishing a Technical Article?
Contact Gwyneth on +44 (0)1727 855574
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