Dried matrix spot direct analysis: evaluating the robustness of a direct elution technique for use in quantitative bioanalysis.

The surge in interest in switching from traditionally used wet plasma to dried matrix spot (DMS) sampling and analysis to support pharmaceutical drug development is due to the significant ethical, financial and data quality advantages on offer. Unfortunately these advantages do not extend to sample bioanalysis, as DMS extraction is more complex than the protein precipitation method typically used for wet plasma analysis. Direct elution techniques coupled to HPLC-MS/MS have been identified as a potential means to counter this additional complexity. The robustness and reproducibility of DMS HPLC-MS/MS data generated using a CAMAG DBS-MS 16 prototype automated direct elution instrument has been demonstrated to meet or exceed results obtained using a conventional manual extraction methodology. The data generated suggest that a simple and fast direct elution method of DMS samples that does not require additional sample or extract clean-up, offers sufficiently robust performance to be compatible with high-sample-throughput quantitative analysis. Further evaluation of the technique and the development of more advanced fully automated direct elution instrumentation is fully warranted.