Serum theophylline analysis by isotope dilution mass spectrometry.
Serum theophylline analysis was attempted using stable isotope dilution mass spectrometry. Theophylline 15N-labelled in position 7 was used as internal standard. The analysis was performed at resolution 3000 by selected ion monitoring with temperature programming. The sample was introduced in underivatized form by means of the direct inlet probe. Good linearity was obtained in the concentration range 5-40 micrograms ml-1 with relative standard deviations less than 6%. The method is simple and permits six samples to be run per hour. Sensitivity permits analysis at 0.5 micrograms ml-1 at a signal to noise ratio 4:1.
Institute of Isotopic and Molecular Technology, Cluj-Napoca, Romania.
M
M
Culea
N
N
Paiibroda
M
M
Chiriac
Z
Z
Moldovan
D006801:Humans; D066298:In Vitro Techniques; D013058:Mass Spectrometry / Q000379:methods; D009590:Nitrogen Radioisotopes; D011865:Radioisotope Dilution Technique; D013806:Theophylline / Q000097:blood*
D009590:Nitrogen Radioisotopes; D013806:Theophylline