Radioimmunoassay and chemical ionization/mass spectrometry compared for plasma cortisol determination.

Abstract We describe a method for determination of cortisol in plasma and urine, based on chemical ionization/mass spectrometry with deuterium-labeled cortisol as the internal standard. The within-run precision (CV) was 2.5-5.7%, the between-run precision 4.6%. Results by this method were compared with those by a radioimmunological method (RIANEN Cortisol, New England Nuclear) for 395 plasma samples. The latter method gave significantly higher (approx. 25%) cortisol values.

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Measurement of sodium valproate in serum by direct-insertion chemical-ionization/mass spectrometry.

Clinical Chemistry ◽

10.1093/clinchem/26.1.0147 ◽

1980 ◽

Vol 26 (1) ◽

pp. 147-149

Author(s):

G M Schier ◽

I E Gan ◽

B Halpern ◽

J Korth

Keyword(s):

Mass Spectrometry ◽

Stable Isotope ◽

Sodium Valproate ◽

Chromatographic Separation ◽

Chemical Ionization ◽

Internal Standard ◽

Ionization Mass Spectrometry ◽

Chemical Ionization Mass Spectrometry ◽

Ionization Mass

Abstract To quantitatively determine sodium valproate, we use a stable isotope-labeled internal standard and chemical-ionization/mass spectrometry, without prior chromatographic separation. The technique is rapid, simple, sensitive, and provides for the routine analysis of 100 microL of serum with good within-day and day-to-day precision. The technique also allows for the simultaneous determination of phenobarbital, mephobarbital, carbamazepine, primidone, and phenytoin.

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Measurement of sodium valproate in serum by direct-insertion chemical-ionization/mass spectrometry.

Clinical Chemistry ◽

10.1093/clinchem/26.1.147 ◽

1980 ◽

Vol 26 (1) ◽

pp. 147-149 ◽

Cited By ~ 4

Author(s):

G M Schier ◽

I E Gan ◽

B Halpern ◽

J Korth

Keyword(s):

Mass Spectrometry ◽

Stable Isotope ◽

Sodium Valproate ◽

Chromatographic Separation ◽

Chemical Ionization ◽

Internal Standard ◽

Ionization Mass Spectrometry ◽

Chemical Ionization Mass Spectrometry ◽

Ionization Mass

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Determination of Daminozide in Apples by Gas Chromatography /Chemical Ionization Mass Spectrometry

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/72.6.984 ◽

1989 ◽

Vol 72 (6) ◽

pp. 984-986

Author(s):

Chao-Hong Liu ◽

Gregory C Mattern ◽

George M Singer ◽

Joseph D Rosen

Keyword(s):

Mass Spectrometry ◽

Gas Chromatography ◽

Chemical Ionization ◽

Internal Standard ◽

Ionization Mass Spectrometry ◽

Chemical Ionization Mass Spectrometry ◽

Ionization Mass ◽

Detection Level ◽

Sample Matrix

Abstract A method using gas chromatography/chemical ionization mass spectrometry (GC/CIMS) for the determination of daminozide residues in apples has been developed. Daminozide was separated from the sample matrix by water extraction and cation exchange, converted to the methyl ester by treatment with HCl-methanol, and determined by GC/CIMS using succinonitrile as an internal standard. The detection level was 0.05 ppm. Recoveries were 92-104% from apples spiked at the 0.05-0.5 ppm levels. Of the 25 apple samples analyzed, only 2 were positive for daminozide (1.04 and 0.32 ppm).

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