Measurement of endogenous uracil and dihydrouracil in plasma and urine of normal subjects by liquid chromatography-tandem mass spectrometry

J Chromatogr B Analyt Technol Biomed Life Sci. 2002 Mar 25;769(1):169-76. doi: 10.1016/s1570-0232(02)00009-0.


A sensitive and specific HPLC-MS-MS method was developed for the determination of endogenous uracil (Ura) and its metabolite dihydrouracil (UH2) in human plasma and urine samples. Plasma samples were extracted with ethyl acetate-isopropanol (85:15, v/v) following added ammonium sulfate, and then separated on a Discovery Amide C16 column with 3% methanol solution as the mobile phase; urine samples were just centrifuged at 2500 g for detection. Quantitation was carried out by LC-MS-MS in the multiple reaction monitoring (MRM) mode. The limits of quantitation of the method for Ura and UH2 were 0.5 and 5 ng ml(-1) (for plasma), and 50 and 100 ng ml(-1) (for urine), respectively. This method can be useful to evaluate the activity of dihydropyrimidine dehydrogenase (DPD), a rate-limiting enzyme of the chemotherapy drug fluoropyrimidine, which will be helpful in investigating subject variation of DPD and adjusting clinical dosage in pyrimidine chemotherapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calibration
  • Chromatography, High Pressure Liquid / methods*
  • Humans
  • Mass Spectrometry / methods*
  • Reference Values
  • Sensitivity and Specificity
  • Uracil / analogs & derivatives*
  • Uracil / blood
  • Uracil / pharmacokinetics*
  • Uracil / urine


  • dihydrouracil
  • Uracil