US 12,276,644 B2
Detection and quantitation of guanidinoacetate, creatine, and creatinine by mass spectrometry
Thomas C. Lynn, San Clemente, CA (US)
Assigned to Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed by Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed on Nov. 15, 2023, as Appl. No. 18/509,590.
Application 18/509,590 is a continuation of application No. 16/056,240, filed on Aug. 6, 2018.
Claims priority of provisional application 62/545,349, filed on Aug. 14, 2017.
Prior Publication US 2024/0085386 A1, Mar. 14, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G01N 30/72 (2006.01); G01N 30/04 (2006.01); G01N 30/88 (2006.01); G01N 33/70 (2006.01)
CPC G01N 30/7266 (2013.01) [G01N 30/72 (2013.01); G01N 30/7233 (2013.01); G01N 30/88 (2013.01); G01N 33/70 (2013.01); G01N 2030/045 (2013.01); G01N 2030/884 (2013.01); G01N 2560/00 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method for determining an amount of guanidinoacetate (GAA), creatine, and creatinine in a single sample, the method comprising:
purifying underivatized GAA, creatine, and creatinine in the single sample;
ionizing the GAA, creatine, and creatinine in the single sample to produce one or more ion(s) of GAA, creatine, and creatinine;
determining an amount of the ion(s) of GAA, creatine, and creatinine by mass spectrometry; wherein:
a fragment ion with the mass/charge ratio of 72.1±0.5 is used to determine the amount of GAA ions; and
the amount of the GAA, creatine, and creatinine ion(s) is related to the amount of GAA, creatine, and creatinine in the single sample.