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component test mix to cope with the different methodologies. To control the suitability testing process, they internally wrote an application called ‘verify’. This proved to be flexible, allowing for different settings and different test mixes. It leant itself to automation without user interaction, and informed the analyst of problems and instrument failures.
The verify process, though setup manually, is then mostly automated. They could add up to 10 components, with most settings as tick- boxes, such as MS positive or negative ionisation modes. When run, the software gave a simple pass or fail result.
An example problem was the presence of unexpected ‘steps’ in chromatograms, which when investigated were a pump problem on a system. They used percentage ‘gradient fit’ to assess if methods used inefficient run times: dividing (adjusted peak capacity – run time) by (peak capacity – run time). This showed up excessive gradient holds and extra dead volumes.
Dunn showed how verify can by fully automated, measuring factors such as retention time, number of peaks, and resolution between peak pairs. They generated a dedicated internal webpage called Hermes which uses the traffic light system to produce a dashboard, to see if systems are working ok.
Their trending software pools data over a time period, for example one month for an instrument. This flagged a particular problem where DMSO was evaporating from the test mixes over time. Thus the peak area was increasing. As a result, they changed to DMF as a solvent and replaced samples regularly, approximately every three weeks.
In general, their retention times were fairly consistent over time, but less so for high pH mobile phases. Keeping track of the peak areas flagged when injection volume increased or decreased. In one example, a negative signal to noise ratio flagged where the data collection rate was different on different instruments.
He led onto future applications of the suitability tests: method transfer, to attempt a guarantee method capture on other systems; and comparison of different instruments using trending.
Dunn concluded that they couldn’t do without it and that this suitability testing procedure ensures high standards are maintained.
I would recommend other students to attend these conferences. The Chromsoc kindly sponsored my attendance with a bursary and the process of claiming this was fairly straightforward. Thanks to all the speakers, Alan Handley for opening the day and John Lough for pertinent comments between talks and support with the bursary/report writing.
20th International Reid Bioanalytical Forum 9-12 September 2013 University of Surrey, Guildford, United Kingdom
The first Forum met in 1975 organised by the late Dr Eric Reid, then Director of the Wolfson Bioanalytical Unit at the University of Surrey. It has run every 2 year since, making this year the 20th. Now run under the auspices of the Chromatographic Soci- ety it retains much of its original character, encouraging young practitioners to learn from more experienced ones, and appreciating the sharing of problems as much as successes.
Still held at the University of Surrey the delegate accommodation is vastly improved over what was offered in 1975, now all accommodation has en-suite facilities and the
conference theatre and exhibition hall are first class. See the evolving programme at:
www.chromsoc.com
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