Measurement of intracellular ribavirin mono-, di- and triphosphate using solid phase extraction and LC-MS/MS quantification.

•Novel approach for separating phosphate moieties for analysis with LC–MS/MS.•Precise, accurate and highly sensitive method for measuring all intracellular ribavirin forms.•Valid method for quantitation of multiple cellular matrices including dried blood spots.•Stable for freeze/thaw and multiple storage conditions in all matrices.