| Autor: |
V I, De Brabandere, P, Hou, D, Stöckl, L M, Thienpont, A P, De Leenheer |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Rapid communications in mass spectrometry : RCM. 12(16) |
| ISSN: |
0951-4198 |
| Popis: |
A new candidate reference method is presented for the determination of thyroxine in serum. The method is based on isotope dilution-liquid chromatography/tandem mass spectrometry using electrospray for ionization. The internal standard used was 13C6-thyroxine, sample pretreatment consisted of protein precipitation and a two-step liquid/liquid extraction procedure, HPLC was performed on a C-18 column with an eluent containing methanol/water/formic acid (60:40:0.1, by volume), and finally thyroxine and its isotopically labeled analogue were measured in the selected reaction monitoring mode for the transitions m/z 777.7--731.7 and m/z 783.7--737.7, respectively. The detection limit for thyroxine was 6 pg, the within-run coefficient of variation was 1.1%. The samples were measured in six-fold: in duplicate on three independent days. The mean overall coefficient of variation of the method was 1.6%. The new method was evaluated by measuring nine control sera previously determined by an existing ID-GC/MS method. The differences between the results of the two methods ranged from-1.6% to +3.3%, with a mean of +0.2%. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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