Analysis of ascorbate and dehydroascorbate in plant extracts by high-resolution selected ion monitoring gas chromatography-mass spectrometry

1997 ◽  
Vol 782 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Gunnar Wingsle ◽  
Thomas Moritz
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
High Resolution ◽  
Plant Extracts ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry

Determination of testosterone in plasma from men by gas chromatography/mass spectrometry, with high-resolution selected-ion monitoring and metastable peak monitoring.

1981 ◽  
Vol 27 (7) ◽  
pp. 1165-1170 ◽  
Author(s):  
E M Finlay ◽  
S J Gaskell
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
High Resolution ◽  
External Quality Assessment ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Internal Standards ◽  
Metastable Peak ◽  
Chromatography Mass Spectrometry

Abstract Highly specific methods are described for determining testosterone in plasma or serum from men. Extract fractions obtained by selective isolation procedures are converted to tert-butyldimethylsilyl (TBDMS) oximes/TBDMS ethers or methyl oximes/TBDMS ethers and analyzed by gas chromatography/mass spectrometry in the high-resolution selected-ion monitoring or metastable peak-monitoring modes. [2H3]Testosterone and unlabeled 17-epitestosterone are used as the respective internal standards. When we applied the two procedures to analysis of samples of pooled plasma and serum used for external quality assessment of routine assays, the results agreed well. Interlaboratory values for mean concentrations obtained by routine immunoassays (y) consistently exceeded values obtained by our technique (x), although the values closely correlated (r = 0.997; y = 1.008x + 0.564 nmol/L).

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