Mass spectrometric determination of eicosapentaenoic acid and docosahexaenoic acid

Patent metadata

Field	Value
Publication number	US-11181537-B2
Application number	US-202016741537-A
Country	US
Kind code	B2
Filing date	Jan 13, 2020
Priority date	Sep 16, 2010
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

The invention relates to the detection of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In a particular aspect, the invention relates to methods for detecting DHA and EPA by mass spectrometry and kits for carrying out such methods.

First claim

That which is claimed is:

1. A method for determining an amount of docosahexaenoic acid (DHA) and/or eicosapentaenoic acid (EPA) in a sample by mass spectrometry, the method comprising:
(i) hydrolyzing the sample containing DHA and/or EPA with an acid;
(ii) extracting DHA and/or EPA from the sample by liquid-liquid extraction;
(iii) ionizing DHA and/or EPA from the sample to generate one or more ions detectable by mass spectrometry;
(iv) determining an amount of DHA and/or EPA ions by single mass spectrometry; and
(v) relating the amount of DHA and/or EPA ions to the amount of DHA and/or EPA in the sample, wherein a limit of detection of the method for DHA is between about 1 μmol/L and 0.25 μmol/L, and a limit of detection of the method for EPA is between about 1 μmol/L and 0.67 μmol/L.

2. The method of claim 1 , wherein said ionizing comprises atmospheric pressure chemical ionization (APCI).

3. The method of claim 2 , wherein said APCI is in negative ionization mode.

4. The method of claim 1 , wherein said ionizing comprises electrospray ionization (ESI).

5. The method of claim 1 , wherein said one or more ions comprise an ion with a mass to charge ratio (m/z) of 327.2±0.5.

6. The method of claim 1 , wherein said one or more ions comprise an ion with a mass to charge ratio (m/z) of 301.2±0.5.

7. The method of claim 1 , wherein said sample comprises human serum or plasma.

8. The method of claim 1 , wherein said acid is hydrochloric acid.

9. The method of claim 1 , wherein said DHA and/or EPA is purified by liquid chromatography prior to ionization.

10. The method of claim 9 , wherein said liquid chromatography comprises high performance liquid chromatography (HPLC).

11. The method of claim 1 , wherein said method comprises determining an amount of an internal standard.

12. The method of claim 11 , wherein said internal standard is a deuterated omega-3 fatty acid.

13. The method of claim 12 , wherein said deuterated omega-3 fatty acid is DHA- 2 H 5 .

14. The method of claim 12 , wherein said deuterated omega-3 fatty acid is EPA- 2 H 5 .

Assignees

• Quest Diagnostics Invest Inc
• Quest Diagnostics Invest Incoporated

Inventors

• Goldman Scott M
• Neidich Julie A

Classifications

• Y10T436/255

  including use of a solid sorbent, semipermeable membrane, or liquid extraction · CPC title

• G01N33/26

  Oils; Viscous liquids; Paints; Inks (G01N33/22 takes precedence) · CPC title

• Y10T436/25125

  Digestion or removing interfering materials · CPC title

• Y10T436/25375

  Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.] · CPC title

• H01J49/0031

  Step by step routines describing the use of the apparatus (H01J49/0081 takes precedence) · CPC title