- 作者：Jianghong Gu ; Offie P. Soldin ; Steven J. Soldin
- 关键词：Free triidothyronine ; Free thyroxine ; Tandem mass spectrometry
- 刊名：Clinical Biochemistry
- 出版年：2007
- 出版时间：December 2007
- 年：2007
- 卷：40
- 期：18
- 页码：1386-1391
- 全文大小：309 K
Design and methods:
An API-5000 tandem mass spectrometer equipped with TurboIonSpray source and Shimadzu HPLC system was employed to perform the analysis using isotope dilution with deuterium labeled internal standard, T4-d5. Four hundred microliters of human plasma/serum was filtered through a Centrifree YM-30 ultrafiltration device by centrifugation, and 450 μL of internal standard in methanol was then added to 150 μL of ultrafiltrate for deproteinization. After centrifugation, 500 μL of supernatant was diluted with 400 μL of distilled de-ionized water and a 650 μL aliquot was injected onto a C-18 column. After washing, the switching valve was activated and the analytes were eluted from the column with a water/methanol gradient into the MS/MS system. Quantification by multiple reaction-monitoring (MRM) analysis was performed in the negative mode.
Results:
The within-day and between-day coefficients of variation (CVs) were ≤ 9 % for FT3 and ≤ 7 % for FT4 at all concentrations tested. Accuracy ranged between 95 % and 105 % . The 2.5th–97.5th percentile for FT3 and FT4 was 0.09–0.4 ng/dL (1.4–6.2 pmol/L) and 0.8–2.1 ng/dL (10–26 pmol/L), respectively. The results correlated only moderately well with the immunoassays.
Conclusions:
We describe an improved simple, accurate and fast isotope dilution tandem mass spectrometry method for the simultaneous determination of FT3 and FT4 in human serum/plasma samples.