Patent ID: 8247236
Filing Date: 2012-08-21
Classification: G01N,Y10T

Abstract:
1. A method of detecting a presence or absence of leucine or an isomer thereof in a sample, the method comprising: providing a test sample; adding to the test sample a first standard comprising a first amino acid that is labeled with one or more heavy atoms, thereby providing a modified test sample, wherein the first amino acid is leucine or an isomer thereof; subjecting the modified test sample to esterification conditions, thereby providing an esterified sample; adding to the esterified sample a second standard comprising an esterified form or a non-esterified form of a second amino acid that is labeled with one or more heavy atoms, thereby providing a modified esterified sample, wherein the second amino acid is leucine or an isomer thereof; evaluating the modified esterified sample using tandem mass spectrometry; and detecting signals indicative of esterified and non-esterified forms of at least two different amino acids in the modified esterified sample, wherein the at least two different amino acids are selected from leucine and isomers of leucine, thereby distinguishing between the at least two amino acids and detecting the presence or absence of leucine or an isomer thereof in the test sample.