caa a22 4500 469129611 CHVBK 20180323133200.0 cr unu---uuuuu 170328e19921201xx s 000 0 eng 10.1007/BF00324651 doi (NATIONALLICENCE)springer-10.1007/BF00324651 A method for the determination of theophylline in serum by isotope dilution mass spectrometry [Elektronische Daten] [F. Susanto, S. Humfeld, C. Niederau, H. Reinauer] Summary: A method for the determination of theophylline in human serum by the isotope dilution/mass spectrometric technique is described. As an internal standard labelled (1,3-15N2-2-13C)theophylline is added to the serum sample. The analyte and internal standard are extracted with chloroform/2-propanol (90:10) and converted to the trimethylsilyl derivatives. The extraction and silylation procedures are checked by adding theophylline and internal standard in various concentrations to blank serum and determining the recovery. The trimethylsilyl derivatives of labelled and non-labelled theophylline are separated and detected by GC-MS with the mass spectrometer set to m/z 252 and 255. The amounts of theophylline in the serum are calculated from the isotope ratios measured by selected ion monitoring. The accuracy, precision and recovery of this GC-MS method are presented and discussed. The coefficient of variation determined from duplicate samples was less than 2.5%. The detection limit was 10 ng/ml at a signal-to-noise ratio of 3:1. Springer-Verlag, 1992 Susanto F. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut Humfeld S. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut Niederau C. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut Reinauer H. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut Fresenius' Journal of Analytical Chemistry Springer-Verlag 344/12(1992-12-01), 549-553 0937-0633 344:12<549 1992 344 216 https://doi.org/10.1007/BF00324651 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00324651 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Susanto F. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut NATIONALLICENCE 700 1- Humfeld S. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut NATIONALLICENCE 700 1- Niederau C. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut NATIONALLICENCE 700 1- Reinauer H. Department of Clinical Biochemistry, Diabetes Research Institute, Heinrich-Heine-University, Auf'm Hennekamp 65, W-4000, Düsseldorf 1, Federal Republic of Germany aut NATIONALLICENCE 773 0- Fresenius' Journal of Analytical Chemistry Springer-Verlag 344/12(1992-12-01), 549-553 0937-0633 344:12<549 1992 344 216 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer