Good sample preparation can make all the difference when it comes to the robustness and performance of an analytical method. Sample preparation is typically employed to concentrate the species of interest prior to analysis or to remove unwanted matrix components. A good sample preparation guide has been published by Agilent – seehttp://www.chem.agilent.com/Library/primers/Public/5991-3326EN_SPHB.pdf
The importance of removing matrix interferences is illustrated by a paper in the journal ‘Analytical Methods’. N-methylpyrrolidine (NMP) is a hydrolysis product of the antibiotic drug cefepime. The official method for the assay of NMP in cefepime fails to separate the two prior to analysis, with the result that NMP continues to be formed as the sample awaits injection. Samples must therefore be injected immediately after preparation, imposing an important and potentially costly constraint (in terms of sample throughput and analyst’s time) on the testing laboratory, especially if a large number of samples require analysis. A simple solid-phase extraction method, however, may be used to remove the majority of cefepime from the final sample extract, significantly improving sample stability. Seehttp://pubs.rsc.org/en/Content/ArticleLanding/2014/AY/C3AY42041H#divAbstract
This work was performed by a team at Quay Pharmaceuticals led by Mark Powell.