Method for detecting and quantifying oxygen in oxidizable compounds by oxidizing a sample with an isotopic oxygen composition different from natural abundance

Patent metadata

Field	Value
Publication number	US-11740212-B2
Application number	US-201616063605-A
Country	US
Kind code	B2
Filing date	Dec 14, 2016
Priority date	Dec 29, 2015
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

The present invention concerns an analytical method that makes use of an oxygen-containing source having a predetermined content of an isotope of oxygen ZO, which is not the same as natural composition and distribution of oxygen isotopes, to detect and/or quantify oxygen in oxidizable compound(s).The analytical method allows detecting and/or quantification with relatively high precision and accuracy oxygen in oxidizable compound(s), even at low content. The method is easy to implement and can be used for in-line analysis.

First claim

The invention claimed is:

1. A method for oxygen analysis in an oxidizable compound or in a mixture of oxidizable compounds, said oxidizable compound(s) being organic compound(s), comprising:
(a) providing a test sample containing at least one oxidizable compound and a reference sample containing at least one oxidizable reference compound which contains at least one chemical element present in the test sample,
(b) submitting separately the test sample and the reference sample to the following steps under the same conditions:
(i) a step of complete oxidative reaction, in which the sample is submitted to an oxidizing medium containing at least one oxidizing agent under conditions efficient to completely oxidize the sample into gaseous oxidized species A a O o , where A is any chemical element different from O present in the sample, a is the number of A atoms, o is the number of O atoms, said oxidizing medium containing a predetermined content of an isotope of oxygen Z O that is not the same as natural composition and distribution of oxygen isotopes, where z is the mass number of the atom,
(ii) a step of detection, in which all the gaseous oxidized species A a O o formed in step (i) are detected by means of a detector device adapted to detect gaseous oxidized species containing different isotopes of oxygen and to generate, for each detected gaseous species, a signal representative of the quantity of said detected gaseous species, the signals obtained for the test sample and for the reference sample being further treated and compared for at least one action chosen from determination of the presence of oxygen and quantification of oxygen,
and prior to step (i), the test sample is introduced into a liquid or gas chromatography device to separate oxidizable compounds having different retention times, which are then submitted separately to steps (i) and (ii).

2. The method according to claim 1 , wherein in step (b), the test sample and the reference sample are volatilized prior to be submitted to step (i) by using a gas chromatography device.

3. The method according to claim 1 , comprising a further step of determination of the chemical formula of said at least one oxidizable compound contained in the test sample.

4. The method according to claim 3 , wherein said step of determination of the chemical formula comprises analyzing said compound(s) using a gas or liquid chromatography device.

5. The method according to claim 1 , where the reference sample does not contain oxygen, further comprises a step (c) for each separated oxidizable compounds having different retention times, this step (c) including, for each gaseous oxidized species A a O o , or for some predetermined gaseous oxidized species A a O o , obtained from complete oxidation step (i):
extracting compound test values from treatment of the signals generated by the detector device at step (ii) for said separated oxidizable compound, said compound test values being the values of each isotopic ratio A a 16 O/A a Z O i 16 O o-i , where indicia i is an integer taking all the values from zero to o, obtained from the corresponding oxidized species A a O o ,
extracting reference values from treatment of the signals generated by the detector device at step (ii) for the reference sample, said reference values being the values of each isotopic ratio A a 16 O/A a Z O i 16 O o-i for which a compound test value has been determined,
determining if the separated oxidizable compound contains oxygen by checking if at least one of its compound test values differs from the corresponding reference value.

6. The method according to claim 5 , wherein
in step a), the reference sample contains at least one reference compound in a known amount and the at least one reference compound contains at least one chemical element different from O present in said at least one oxidizable compound contained in, or consisting, the test sample,
and wherein, when step (c) has determined that a separated oxidizable compound contains oxygen, the analytical method further comprises, for each separated oxidizable compound containing oxygen:
a quantification step (d) comprising:
extracting from treatment of the signals generated by the detector device at step (ii) for this oxygen-containing separated oxidizable compound, values representative of intensities of the signals generated at step (ii) for all the isotopes of a predetermined species A a O o , where element A is present in both the separated oxidizable compound and reference sample, and summing these intensity values,
extracting from treatment of the signals generated by the detector device at step (ii) for the reference sample, values representative of intensities of the signals generated at step (ii) for all the isotopes of the predetermined species A a O o , and summing these intensity values,
from the known amount of A contained in the reference sample and from the above sums, calculating the amount of A in the oxygen-containing separated oxidizable compound, and calculating the amount of O in the oxygen-containing separated oxidizable compound or the amount of the oxygen-containing separated oxidizable compound by means of the chemical formula of the oxygen-containing separated oxidizable compound determined in a previous step.

7. The method according to claim 6 , where the reference sample does not contain oxygen and further comprising a step (c′) including, for each gaseous oxidized species A a O o , or for some predetermined gaseous oxidized species A a O o , obtained from complete oxidation step (i):
extracting test values from treatment of the signals generated by the detector device at step (ii) for the test sample, said test values being the values of each isotopic ratio A a 16 O/A a Z O i 16 O o-i where indicia i is an integer taking all the values from 0 to o,
extracting reference values from treatment of the signals generated by the detector device at step (ii) for the reference sample, said reference values being the values of each isotopic ratio A a 16 O/A a Z O i 16 O o-i for which a test value has been determined,
determining if the test sample contains oxygen by checking if at least one of the test values differs from the corresponding reference value.

8. The method according to claim 5 , wherein:
in step (a), the reference sample contains at least one reference compound in a known amount and the at least one reference-compound contains at least one chemical element different from O present in said at least one oxidizable compound contained in, or consisting, the test sample,
step (c) or (c′) is performed for all the gaseous oxidized species A a O o obtained from complete oxidation step (i) and detected in step (ii),
and wherein the analytical method further comprises:
a step (d′) for determining the quantity of oxygen in the test sample, including, for each gaseous oxidized species A a O o for which it has been determined at step (c) or (c′) that the isotopic ratio value of the test sample, optionally the isotopic ratio value of a separated oxidizable compound, differs from the value of the same isotopic ratio of the reference sample, showing the presence of oxygen originating from the test sample, optionally from the separated oxidizable compound:
extracting from treatment of the signals generated by the detector device at step (ii) for the test sample, optionally for the separated oxidizable compound, values representative of intensities of the signals generated at step (ii) for all the isotopes of this A a O o species, and summing these intensity values,
extracting from treatment of the signals generated by the detector device at step (ii) for the reference sample, values representative of intensities of the signals gener

Assignees

• Totalenergies Onetech
• Univ Oviedo
• Univ De Pau Et Du Pays De Ladour
• Centre Nat Rech Scient
• Univ De Pau Et Des Pays De Ladour
• Centre Nat Rech Scient

Inventors

• Giusti Pierre
• Ruiz Encinar Jorge
• Moldovan Mariella
• Bouyssiere Brice

Classifications

• G01N31/005 Primary

  investigating the presence of an element by oxidation (G01N31/12 takes precedence) · CPC title

• G01N31/12 Primary

  using combustion (G01N25/20 takes precedence) · CPC title

• G01N30/72

  Mass spectrometers {(mass spectrometers per se H01J49/00)} · CPC title

• G01N30/8679

  Target compound analysis, i.e. whereby a limited number of peaks is analysed · CPC title

• G01N33/2841

  Gas in oils, e.g. hydrogen in insulating oils · CPC title