title: Quantification of small molecules in plasma with direct analysis in real time tandem mass spectrometry, without sample preparation and liquid chromatographic separation.
abstract: Recently, a new ion source, Direct Analysis in Real Time (DART), has been introduced which allows direct biological sample introduction into a mass spectrometry (MS) system. The elimination of conventionally required sample preparation and separation by high-performance liquid chromatography (HPLC) prior to MS analysis represents a remarkable opportunity to reduce assay turn-around time, environmental impact and capital/manpower investment. This new technology initially was used in various qualitative applications to directly detect chemicals on solid surfaces, in liquids and gases. In this study, a DART source operating under ambient pressure with ground potential was installed onto a Sciex 4000 tandem mass spectrometer and employed in the sample analysis of plasma based on direct introduction into the DART-MS/MS system. Reasonable precision and accuracy (%CV and %Error, both <10%) were achieved of a significant number of compounds tested in biological fluids. In addition, the limit of detection for 80% of the tested compounds reached 5 ng/mL or lower which is sufficient for pharmaceutical drug discovery support. Finally, experimental conditions that significantly impacted assay performance were investigated with respect to optimization and limitation. Because of its simplicity, fast data acquisition (3-5 s) and low cost, DART has the potential to significantly impact quantitative pharmaceutical analysis in biological matrices.
authors.affiliation: Department of Drug Metabolism and Pharmacokinetics, Roche Palo Alto, LLC, 3431 Hillview Ave., Palo Alto, CA 94304, USA. yeping.zhao@roche.com
authors.forename: Yeping
authors.initials: Y
authors.lastname: Zhao
authors.forename: Michelle
authors.initials: M
authors.lastname: Lam
authors.forename: Danlin
authors.initials: D
authors.lastname: Wu
authors.forename: Rowena
authors.initials: R
authors.lastname: Mak
mesh_terms: D001923:Brain Chemistry; D002121:Calcium Channel Blockers / Q000097:blood / Q000493:pharmacokinetics; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D003199:Computer Systems; D006801:Humans; D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations / Q000032:analysis; D010599:Pharmacokinetics; D010949:Plasma / Q000737:chemistry*; D015203:Reproducibility of Results; D012996:Solutions; D053719:Tandem Mass Spectrometry; D014700:Verapamil / Q000097:blood / Q000493:pharmacokinetics
chemical_list: D002121:Calcium Channel Blockers; D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations; D012996:Solutions; D014700:Verapamil