Measurement of plasma testosterone by gas chromatography-negative-ion mass spectrometry using pentafluoropropionic derivatives.
Plasma testosterone was measured by gas chromatography-negative-ion chemical ionisation mass spectrometry (GC-MS). The testosterone was extracted from plasma using home-made Extrelut columns and diethyl ether elution. It was quantified as the pentafluoropropionate (PFP) derivative by selected-ion monitoring at m/z 560 (testosterone) and 563 (d3-testosterone), accounting for about 34% of the total ion. The characteristics of the method were: extraction recovery about 95%; linearity over the range 1.7-71.5 nmol l-1 with linear regression equation y = 1.41x + 0.0217, r = 0.999; detection limit 3.5 fmol injected with a signal-to-noise ratio of 7.4; within-day variation, 3% for GC-MS, and 5.8% for the whole process; day-to-day coefficient of variation, 6.6-11%, depending on the concentrations. There was a good correlation between the results obtained by GC-MS and RIA (r = 0.994), but the GC-MS values were significantly lower (p < 0.05) than those obtained by RIA.
Legrand
C
C
Laboratory of Biochemistry B, C.H.R.U. Nancy, France.
Dousset
B
B
Tronel
H
H
Belleville
F
F
Nabet
P
P
D000328:Adult; D005466:Fluorocarbons / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D013739:Testosterone / Q000097:blood*
D005466:Fluorocarbons; D007202:Indicators and Reagents; D013739:Testosterone; C033093:perfluoropropionic acid