US 11,885,820 B2
Vitamin D metabolite determination utilizing mass spectrometry following derivatization
Brett Holmquist, Mission Viejo, CA (US); Nigel J. Clarke, Vista, CA (US); and Richard E Reitz, Las Vegas, NV (US)
Assigned to Quest Diagnostics Investments Incorporated, Wilmington, DE (US)
Filed by Quest Diagnostics Investments Incorporated, Wilmington, DE (US)
Filed on Aug. 20, 2021, as Appl. No. 17/408,298.
Application 17/408,298 is a continuation of application No. 16/588,709, filed on Sep. 30, 2019, granted, now 11,105,821, issued on Aug. 31, 2021.
Application 16/588,709 is a continuation of application No. 15/489,551, filed on Apr. 17, 2017, granted, now 10,429,398, issued on Oct. 1, 2019.
Application 15/489,551 is a continuation of application No. 13/287,012, filed on Nov. 1, 2011, granted, now 9,625,477, issued on Apr. 18, 2017.
Application 13/287,012 is a continuation of application No. 13/115,935, filed on May 25, 2011, granted, now 8,076,157, issued on Dec. 13, 2011.
Application 13/115,935 is a continuation of application No. 12/630,790, filed on Dec. 3, 2009, granted, now 7,977,117, issued on Jul. 12, 2011.
Prior Publication US 2022/0043011 A1, Feb. 10, 2022
Int. Cl. G01N 33/82 (2006.01); G01N 30/72 (2006.01); G01N 30/88 (2006.01); H01J 49/00 (2006.01)
CPC G01N 33/82 (2013.01) [G01N 30/7233 (2013.01); G01N 30/88 (2013.01); G01N 2030/8813 (2013.01); H01J 49/0031 (2013.01); H01J 49/0045 (2013.01); Y10T 436/203332 (2015.01); Y10T 436/24 (2015.01)] 7 Claims
OG exemplary drawing
 
1. A method for determining an amount of one or more vitamin D metabolites in a sample by mass spectrometry, the method comprising:
(i) adding one or more internal standards to a sample;
(ii) precipitating one or more vitamin D metabolites and one or more internal standards with acetonitrile;
(iii) subjecting the one or more vitamin D metabolites and one or more internal standards to 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) derivatization,
(iv) subjecting the one or more PTAD derivatized vitamin D metabolites and one or more PTAD derivatized internal standards to solid phase extraction (SPE),
(v) purifying the one or more PTAD derivatized vitamin D metabolites and one or more internal standards by turbulent flow liquid chromatography (TFLC);
(vi) ionizing the one or more PTAD-derivatized vitamin D metabolites derivatives and the one or more PTAD-derivatized internal standards to produce one or more ions comprising a mass/charge (m/z) ratio selected from the group consisting of 550.4, and 568.4, and which are detectable by mass spectrometry; and
(vii) determining an amount of the one or more PTAD-derivatized vitamin D metabolites. ions and the one or more PTAD-derivatized internal standards ions by mass spectrometry, wherein the amount of the one or more PTAD-derivatized vitamin D metabolites is determined from the amount of ions.