US 12,282,032 B2
Vitamin D metabolite determination utilizing mass spectrometry following derivatization
Brett Holmquist, West Hills, CA (US); Nigel J. Clarke, Oceanside, CA (US); and Richard E Reitz, San Clemente, CA (US)
Assigned to Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed by Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed on Dec. 11, 2023, as Appl. No. 18/535,618.
Application 18/535,618 is a continuation of application No. 17/408,298, filed on Aug. 20, 2021, granted, now 11,885,820.
Application 17/408,298 is a continuation of application No. 16/588,709, filed on Sep. 30, 2019, granted, now 11,105,821.
Application 16/588,709 is a continuation of application No. 15/489,551, filed on Apr. 17, 2017, granted, now 10,429,398.
Application 15/489,551 is a continuation of application No. 13/287,012, filed on Nov. 1, 2011, granted, now 9,625,477.
Application 13/287,012 is a continuation of application No. 13/115,935, filed on May 25, 2011, granted, now 8,076,157.
Application 13/115,935 is a continuation of application No. 12/630,790, filed on Dec. 3, 2009, granted, now 7,977,117.
Prior Publication US 2024/0103022 A1, Mar. 28, 2024
This patent is subject to a terminal disclaimer.
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)] 4 Claims
OG exemplary drawing
 
1. A method for determining an amount of 1α,25-dihydroxyvitamin D2 (1α,25(OH)2D2) in a sample by mass spectrometry, the method comprising:
adding an internal standard to the sample;
precipitating 1α,25(OH)2D2 and the internal standard with acetonitrile;
subjecting the 1α,25(OH)2D2 and the internal standard to 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) derivatization to form PTAD derivatized 1α,25(OH)2D2 and PTAD derivatized internal standard;
subjecting the PTAD derivatized 1α,25(OH)2D2 and the PTAD derivatized internal standard to solid phase extraction;
purifying the PTAD derivatized 1α,25(OH)2D2 and the PTAD derivatized internal standard by turbulent flow liquid chromatography;
ionizing the PTAD-derivatized 1α,25(OH)2D2 and the PTAD derivatized internal standard to produce ions of PTAD derivatized 1α,25(OH)2D2 comprising ions with a m/z ratio of 550.4, 568.4, and 586.4, and ions of PTAD derivatized internal standard comprising ions with a m/z ratio of 556.3, 574.4, and 592.4; and
determining an amount of the PTAD-derivatized 1α,25(OH)2D2 ions and the PTAD-derivatized internal standard ions by mass spectrometry.