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  • Determination of 17alpha-hydroxypregnenolone in human plasma by routine isotope dilution mass spectrometry using benchtop gas chromatography-mass selective detection.

Determination of 17alpha-hydroxypregnenolone in human plasma by routine isotope dilution mass spectrometry using benchtop gas chromatography-mass selective detection.

Steroids (2001-08-28)
S A Wudy, M Hartmann, C Solleder, J Homoki
ABSTRACT

A first assay based on stable isotope dilution/gas chromatography-mass spectrometry has been developed for plasma 17alpha-hydroxypregnenolone, the leading marker of 3beta-hydroxysteroid dehydrogenase deficiency. Equilibration of plasma with internal standard was followed by solid phase extraction. After clean up using Sephadex LH-20 mini columns, heptafluorobutyrates were prepared as derivatives. Quantification was achieved by selected ion monitoring of m/z 467.0 (analyte) and m/z 471.0 (internal standard). 0.030 pmol of 17alpha-hydroxypregnenolone gave a signal to noise ratio of 3.7. Calibration plot was linear. Spiking experiments showed good accuracy with relative errors < 3.7%. Intraassay precision CV was 8.3% and interassay precision CV was 5.6%. Requiring small amounts of plasma, the rapid, convenient work up and the application of bench top GC/MS instrumentation proved our method suitable for routine clinical use in adults and children.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
L-Valine, from non-animal source, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%
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SAFC
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Supelco
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Supelco
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