Theophylline
| Analyt: | Theophylline |
| Matrix: | Serum |
| Measuring Method: | GC-ID/MS |
| Standard: | Cerilliant IMPC-051-01 Primary Standard Theophylline |
| Internal Standard: | ¹³C,¹⁵N₂-Theophyllin |
| Sample Processing: | Samples are spiked gravimetrically with internal standard, equilibrated, then precipitated with TCA, centrifuged and the supernatant is extracted into chloroform/2-propanol, centrifuged and the lower phase evaporated to dryness. Derivatisation is performed with MSTFA. |
| Measurement: | Measurement at m/z 237 and m/z 240 or at m/z 252 and m/z 255 |