Page 156 - Advances in Forensic Applications of Mass Spectrometry - Jehuda Yinon

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of 100 mg of decontaminated hair were incubated in 1 ml 1 N NaOH, 15
min at 95˚C, in presence of 1 ng of testosterone-d used as internal standard
3
(IS). After cooling, the homogenate was neutralized with 1 ml 1 M HCl, and
2 ml of 0.2 M phosphate buffer (pH 7.0) were added.
The Isolute C18 columns were conditioned with 3 ml of methanol, fol-
lowed by 2 ml of deionized water. After sample addition, the columns were
washed twice with 1 ml of deionized water. After column drying, analyte
elution occured with the addition of 3 aliquots of 0.5 ml of methanol. The
eluant was evaporated to dryness under nitrogen flow, and the residue recon-
stitued in 1 ml of 0.2 M phosphate buffer (pH 7.0). A further purification
step was achieved by the addition of 100 mg of Na CO /NaHCO (1:10, w/w)
2 3 3
and 2 ml of pentane. After agitation and centrifugation, the organic phase
was removed and evaporated to dryness. The residue was derivatized by
adding 50 ml MSTFA/NH I/2-mercaptoethanol (1000/2/5; v/v/v) and then
4
incubated for 20 min at 60˚C.
A 2-ml aliquot of the derivatized extract was injected into the column of
a Hewlett–Packard gas chromatograph (6890 Series). The flow of carrier gas
through the column (HP5-MS capillary column, 5% phenyl-95% methylsil-
oxane, 30 m ¥ 0.25 mm i.d. ¥ 0.25 mm film thickness) was 1 ml/min.
The injector temperature was 270˚C and splitless injection was employed
with a split valve off-time of 1 min. The column oven temperature was
programmed to rise from an initial temperature of 150˚C, maintained for 1
min, to 295˚C at 5˚C/min.
The detector was a Finnigan TSQ 700 operated in the electron impact
mode and in selected reaction monitoring. The parent ions, m/z 417, 432,
432, 434, and 435 for DHEA, testosterone, epitestosterone, DHT, and the IS,
respectively, were selected in the first quadrupole. The corresponding daugh-
ter ions, m/z 237 and 327, 196 and 209, 196 and 209, 143 and 195, and 209
for DHEA, testosterone, epitestosterone, DHT, and the IS, respectively, were
selected in the third quadrupole after collision with argon at a cell pressure
at 0.6 mTorr. The collision offset voltage was –8 V. The electron multiplier
was operated at 1900 V.
Results shown in Table 3.2 were obtained from about one hundred hair
samples.

Table 3.2 Compendium of Results for Endogenous
Anabolics in Hair
Compounds Mean (pg/mg) Mini (pg/mg) Maxi (pg/mg)
Testosterone 8.4 1.5 64.2
Epitestosterone 2.4 0.5 17.6
DHEA 16.9 0.8 94.2
DHT 1.8 0.5 4.2

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