Does Your HPLC-MS Data Look Better Than it Really Is?
By S. Sitaraman , A. Witkowski , J. Plassard , B. Schrader , K. Szczap , and B. Beato
Purpose: The selectivity of LC/MS/MS yields chromatograms appearing deceptively clean. Interferences such as plasticizers and matrix components can adversely affect quantitation via ion suppression. Co-eluting and/or isomeric ;metabolites in incurred samples can also interfere with quantitation. An LC/MS/MS assay for a drug and one metabolite (M1) provides a case study demonstrating ways to locate and handle various potential interferences.
Methods: A protein precipitation method was used to prepare plasma samples from dosed and non-dosed rats and monkeys. Extracts were collected in plastic 96-well plates, with the drug, metabolite, and various interferences monitored by LC/MS/MS.