Quantification of Fluticasone Propionate and Salmeterol Xinafoate in Plasma at the Sub pg/mL Level Using UPLC/MS/MS  

Sensitivity has been the driving force in the bioanalysis and DMPK arena for the last 15-20 years. The introduction of tandem quadrupole ESI mass spectrometry into the bioanalysis laboratory in the early 1990’s saw a step-change in the sensitivity and specificity of bioanalytical assays. Prior to this achieving sensitivities in the ng/mL range required complicated method development, elegant LC methods, elaborate solid-phase or liquid-liquid extraction processes to process large volumes of sample and even chemical modification of the analyte to impart better detection characteristic. The introduction of ESI tandem quadrupole MS changed the face of bioanalysis. Now sensitivities in the ng/mL range or could be achieved on virtually every molecule, from just a few hundred microlitres of sample without the need for complex sample preparation or derivitisation. Twenty years on and the pace of MS innovation and chromatographic science development means that sensitivities in the pg/mL range or below are now possible, even for the most challenging of molecules.