Patent ID: 7494822
Filing Date: 2009-02-24
Classification: G01N,Y10T

Abstract:
1. A method of one step synthesis of stable isotope labeled internal standards and derivatizing reaction for the purpose of quantification of a carboxylic acid in an aqueous sample comprising the steps of: a) synthesizing labeled said carboxylic acid ester for use as labeled internal standard by reaction of an authentic sample of carboxylic acid with a labeled derivatizing reagent having at least one stable isotope atom; b) combining a known amount of said labeled carboxylic acid ester internal standard with said aqueous sample comprising said carboxylic acid; c) contacting said resulting sample with a non labeled version of said labeled derivatizing reagent under basic conditions to convert said carboxylic acid in said aqueous sample into a carboxylic acid ester of identical structure as that of said carboxylic acid ester internal standard with the exception of the stable isotope atoms; d) extracting said sample to isolate said carboxylic acid ester and said labeled carboxylic acid ester internal standard; and e) quantifying said carboxylic acid ester using said labeled carboxylic acid ester internal standard by mass spectrometry to determine the concentration of said carboxylic acid in said sample.