AstraZeneca moves to on-line liquid scintillation counting
26 August 2005
AstraZeneca is making the transition from fraction collection to on-line liquid scintillation counting at its Charnwood research and development centre in the UK.
The centre's Development Drug Metabolism and Bioanalysis Department is validating an LC-ARC StopFlow radio-isotope counting system from AIM Research that will supersede its current microplate scintillation counter.
"Loading and unloading microplates is a slow and tedious procedure, and the low plate capacity of our fraction collector limits us to single runs so we can't run batches overnight or at weekends," said Jonathan Attwood, the department's senior research scientist.
"LC-ARC counts on-line in the detector flow cell so it has none of these drawbacks, which will make the business of working with samples with low-level radioactivity much more convenient.
"We realised the potential of the system when AIM Research demonstrated it to us several years ago, but initially we had reservations about the lack of local technical support.
"That obstacle was removed when LabLogic Systems took on responsibility for marketing the product in Europe, because we already have a good working relationship with them. The detector we will be using with the LC-ARC is LabLogic's Beta-RAM, for example, and we are also long-standing users of their Debra and Laura software."
LC-ARC StopFlow detects peaks down to 20 dpm on-line by halting the flow of the sample in the flow cell to allow longer count times.
It can be used with many different HPLC systems, giving sharper peak resolution, accurate quantification of volatile metabolites/degradates and accurate column recovery. Any 'memory' effect in the flow cell is reduced by cleaning before the introduction of the next sample.
If required, the flow can be split between the radio detector and a mass spectrometer to allow simultaneous profiling and identification of radio-labelled compounds.
The software supplied with the system automates the whole process, controlling the autosampler, HPLC pumps and radio flow detector as well as the StopFlow itself. It also calculates the limits of detection and quantitation, giving greater confidence in the accuracy of the results.