Jascindra Ravi et al 2010 Metrologia 47 08022 doi:10.1088/0026-1394/47/1A/08022
Jascindra Ravi1, David Schiffmann1, Ratna Tantra1, Simon Cox1, Jonathan Eady1, Christopher Jones2, John S Vrettos3, Richard P Affleck3, Julie DeSa Lorenz4, Yasushi Shigeri5, Sheng Linghui6, Liu Jun6, Robert Willows7, Philippe Charlet8, Yves Dupont9, Curtis W Meuse10, Marc J A Bailey1 and Alex E Knight1
Show affiliationsCircular dichroism is a spectroscopic technique that is widely used to obtain information about protein structure, and hence is an important tool with many applications, including the characterization of biopharmaceuticals. However, there is a lack of confidence in the technique, arising from an observed lack of comparability in the data obtained by different laboratories, or even different operators. In this study, we set out to determine the extent of comparability in the technique, by comparing the results obtained from identical protein samples by a panel of worldwide laboratories. The laboratories chosen were either national measurement institutes (NMIs) or expert laboratories nominated by an NMI. We also aimed to identify the main factors contributing to any lack of measurement comparability. Data were analysed using PCA and SIMCA methods, and we show these statistical techniques are ideal for analysing large amounts of this type of spectroscopic data. We found a startling lack of comparability among laboratories, but we also found that most of the variability arose from relatively simple problems, which can be avoided by following simple guidelines. We believe that the lack of an absolute reference or measurement traceability in circular dichroism contributes to a lack of confidence in the technique.
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Issue 1A (Technical Supplement 2010)
Jascindra Ravi et al 2010 Metrologia 47 08022
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