LAUSR

Abstract The enantioselective analytical method for trace ketoprofen (KET) in human saliva was developed for the first time using liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) combined with a derivatization using a chiral reagent, (S)‑1‑methyl‑4‑(5‑(3‑aminopyrrolidin‑1‑yl)‑2,4‑dinitro‑phenyl)piperazine (APy‑PPZ). The APy‑PPZ derivatization enabled highly sensitive detection (detection limit, 0.5 fmol on column) and complete separation with high resolution (Rs = 4.3) of KET enantiomers. The calibration curves of both KET enantiomers in saliva were linear in the concentration range of 5–500 nM. The developed method showed good analytical performance with relative standard deviations (RSDs) below 2.6% and good accuracy (100.5–105.9%) through intra- and inter-assay and gave a potential for practical application to the quantitative determination of KET in human saliva.