Chemistry: analytical and immunological testing – Nuclear magnetic resonance – electron spin resonance or other...
Reexamination Certificate
2003-09-30
2009-02-24
Gakh, Yelena G (Department: 1797)
Chemistry: analytical and immunological testing
Nuclear magnetic resonance, electron spin resonance or other...
C436S129000
Reexamination Certificate
active
07494822
ABSTRACT:
Method of identification and quantitative analysis of carboxylic acid(s) in a sample by mass spectrometry using stable isotope labeled internal standard is provided. Said internal standard is prepared by reaction of an authentic sample of said carboxylic acid with a stable isotope labeled reagent, and is added to a sample containing said carboxylic acid. Said carboxylic acid in said sample is then quantitatively converted to a chemical compound of identical structure, except the stable isotope atoms, as that of said internal standard using a non-labeled reagent. Said sample is then extracted and the extract is analyzed by mass spectrometry. Identification and quantification of said carboxylic acid are made from a plot of ion ratio of said converted carboxylic acid to said internal standard versus carboxylic acid concentration.
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Nguyen Duc T.
Nguyen Hoa D.
Nguyen Trinh D.
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