Extraction of steroids from plasma with reversed phase C18 cartridges

Cannell, G. R.; Galligan, John; Mortimer, Robin H.; Thomas, Mansel J.

doi:10.1016/0009-8981(82)90146-2

Cited by 22 publications

(2 citation statements)

References 8 publications

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“…Steroids were freshly made weekly and GE daily. Fetal outflow samples were collected over 3-5-minute intervals and 14 C-antipyrine and steroids extracted using a modification of the method described by Cannell et al (1982). Briefly, the fetal effluent was centrifuged to pellet debris, acidified with HCl, extracted through Sep-pak Plus cartridges (Waters, UK) and eluted with ethyl acetate.…”

Section: Sample Collection and Analysismentioning

confidence: 99%

Placental 11β‐hydroxysteroid dehydrogenase: a key regulator of fetal glucocorticoid exposure

Benediktsson

Calder

Edwards

et al. 1997

Clinical Endocrinology

507

305

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Section: Sample Collection and Analysismentioning

confidence: 99%

Placental 11β‐hydroxysteroid dehydrogenase: a key regulator of fetal glucocorticoid exposure

Benediktsson

Calder

Edwards

et al. 1997

Clinical Endocrinology

507

305

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show abstract

“…An appropriate amount of cortisol- d 3 was added to each aliquot to give an ∼1:1 ratio of analyte to internal standard. Each sample was acidified to pH 1.5 with 6 mL of 0.5 mol/L phosphoric acid and equilibrated at room temperature (22 °C) for 1 h. After equilibration, cortisol was isolated from the serum matrix using C 18 Sep-Pak solid-phase extraction cartridges. − Each sample was loaded at a rate of 3−4 mL/min onto a cartridge previously conditioned by wetting with 5 mL of methanol, followed by 5 mL of water. The cartridge was then washed with 12 mL of water, followed by 5 mL of water−acetonitrile (80:20 by volume).…”

Section: Methodsmentioning

confidence: 99%

Development and Evaluation of a Candidate Reference Method for the Determination of Total Cortisol in Human Serum Using Isotope Dilution Liquid Chromatography/Mass Spectrometry and Liquid Chromatography/Tandem Mass Spectrometry

Tai

Welch

2004

Anal. Chem.

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Cortisol is an important diagnostic marker for the production of steroid hormones, and accurate measurements of serum cortisol are necessary for proper diagnosis of adrenal function. A candidate reference method involving isotope dilution coupled with liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. An isotopically labeled internal standard, cortisol-d(3), was added to serum, followed by equilibration and solid-phase and ethyl acetate extractions to prepare samples for liquid chromatography/mass spectrometry electrospray ionization (LC/MS-ESI) and liquid chromatography/tandem mass spectrometry electrospray ionization (LC/MS/MS-ESI) analyses. (M + H)(+) ions at m/z 363 and 366 for cortisol and its labeled internal standard were monitored for LC/MS. The transitions of (M + H)(+) --> [(M + H)(+) - 2H(2)O] at m/z 363 --> 327 and 366 --> 330 were monitored for LC/MS/MS. The accuracy of the measurement was evaluated by a comparison of results of this candidate reference method on lyophilized human serum reference materials for cortisol [Certified Reference Materials 192 and 193] with the certified values determined by gas chromatography/mass spectrometry reference methods and by a recovery study for the added cortisol. The results of this method for total cortisol agreed with the certified values within 1.1%. The recovery of the added cortisol ranged from 99.8% to 101.0%. This method was applied to the determination of cortisol in samples of frozen serum pools. Excellent precision was obtained with within-set CVs of 0.3%-1.5% and between-set CVs of 0.04%-0.4% for both LC/MS and LC/MS/MS analyses. The correlation coefficients of all linear regression lines ranged from 0.998 to 1.000. The detection limits (at a signal-to-noise ratio of approximately 3-5) were 10 and 15 pg for LC/MS and LC/MS/MS, respectively. This method, which demonstrates good accuracy and precision, and is free from interferences from structural analogues, qualifies as a candidate reference method and can be used as an alternative reference method to provide an accuracy base to which the routine methods can be compared.

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Total steroid profiling with capillary GC. Details on sample preparation

Vanluchene¹,

Vandekerckhove²

1985

J. High Resol. Chromatogr.

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The accuracy and reproducibility of steroid and steroid conjugate determinations using capillary GC are evaluated. It is possible to analyze many unconjugated steroids, steroid sulfates, and some steroid glucuronides simultaneously, simply by using group fractionation based on successive hydrolysis and solvent extraction steps. However, a reliable determination of corticosteroid glucuronides can only be obtained after previous isolation of the glucuronides as a group, with ion exchange chromatography. In complex chromatograms, the combined use of nitrogen specific detection and flame ionization detection facilitates peak identification.

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Extraction of steroids from plasma with reversed phase C18 cartridges

Cited by 22 publications

References 8 publications

Placental 11β‐hydroxysteroid dehydrogenase: a key regulator of fetal glucocorticoid exposure

Placental 11β‐hydroxysteroid dehydrogenase: a key regulator of fetal glucocorticoid exposure

Development and Evaluation of a Candidate Reference Method for the Determination of Total Cortisol in Human Serum Using Isotope Dilution Liquid Chromatography/Mass Spectrometry and Liquid Chromatography/Tandem Mass Spectrometry

Total steroid profiling with capillary GC. Details on sample preparation

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