An investigation into the critical operating parameters affecting high throughput LC analysis within the pharmaceutical industry

Woodward, J., 2003. An investigation into the critical operating parameters affecting high throughput LC analysis within the pharmaceutical industry. MPhil, Nottingham Trent University.

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Optimisation of liquid chromatography (LC) and mass spectrometry (MS) parameters has enabled rapid methodologies to be developed which significantly increase sample throughput. Stationary phase characterisation highlighted the importance of selecting a column with minimum acidic silanol content for high efficiencies for the analysis of basic analytes. DryLab optimisation software can be used to accurately predict separations on short, narrow i.d. columns packed with small particles running at high flow rates. The need to select appropriate detector flow cells, optimise response times, and extra column volumes for rapid analysis has been shown. To ensure that the rate limiting step in rapid analysis is not the injection timing, rapid injections, or an overlap injection mode which buries the injection time in the run time of the method can be used.

The sensitivity of an LC/MS analysis can be enhanced by selecting an appropriate buffer and buffer concentration. The choice of organic modifier was shown to have less of an impact on sensitivity although the use of a low viscosity organic solvent gave rise to low column pressures allowing analysis at higher flow rates than would otherwise be used. The electrospray source was shown to exhibit concentration dependent sensitivity whilst the APCI source exhibited mass flow sensitivity. A comparison between APCI and ESI showed little drift in response over a 16 hour run. Using an analogue output from the MSD a single SIM trace was taken from the MSD into a chromatography data system for processing. The analogue output allowed the processing of data for a typical overnight ran to be cut from 3 hours to under 30 minutes.

Using the optimised LC and MS parameters rapid LC/MS methods were developed. Using MS as a detection technique allowed the increased speed of analysis compared with UV detection due to complete separation of the analyte from its impurities not being necessary. MS detection can increase the sensitivity of the method by as much as 100 times over that of UV detection which makes it suitable for the analysis of low concentration samples. Combine this with the use of column switching approaches to remove non-volatile materials and LC/MS becomes a very important technique for pharmaceutical analysis.

Item Type: Thesis
Creators: Woodward, J.
Date: 2003
ISBN: 9781369316971
Divisions: Schools > School of Science and Technology
Record created by: Linda Sullivan
Date Added: 01 Oct 2020 13:41
Last Modified: 20 Sep 2023 09:11

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