Determination of serum creatinine by isotope dilution method using discharge-assisted thermospray liquid chromatography/mass spectrometry.

A discharge-assisted thermospray (plasmaspray) liquid chromatography/mass spectrometric method for the determination of serum creatinine is described. The method incorporates stable isotope dilution using (D3)creatinine as an internal standard. Separation is performed in reversed-phase high-performance liquid chromatography using 0.01 M aqueous ammonium acetate as a flow solvent. Effluents are directly introduced to the mass spectrometer and [MH]+ ions are monitored during LC/MS using the selected ion monitoring method. Satisfactory agreement between the analytical result and the certified value of the serum sample of standard reference material and relative standard deviation ranging from 0.6% to 1.2% was obtained.