GB2309782A - Oxygen isotopic analysis in water samples - Google Patents
Oxygen isotopic analysis in water samples Download PDFInfo
- Publication number
- GB2309782A GB2309782A GB9701901A GB9701901A GB2309782A GB 2309782 A GB2309782 A GB 2309782A GB 9701901 A GB9701901 A GB 9701901A GB 9701901 A GB9701901 A GB 9701901A GB 2309782 A GB2309782 A GB 2309782A
- Authority
- GB
- United Kingdom
- Prior art keywords
- oxygen
- water
- bed
- gas
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 38
- 239000001301 oxygen Substances 0.000 title claims abstract description 26
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 26
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 25
- 238000004458 analytical method Methods 0.000 title claims abstract description 21
- 230000000155 isotopic effect Effects 0.000 title claims description 12
- 239000000463 material Substances 0.000 claims abstract description 17
- 229910021583 Cobalt(III) fluoride Inorganic materials 0.000 claims abstract description 15
- WZJQNLGQTOCWDS-UHFFFAOYSA-K cobalt(iii) fluoride Chemical compound F[Co](F)F WZJQNLGQTOCWDS-UHFFFAOYSA-K 0.000 claims abstract description 15
- 239000012159 carrier gas Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 21
- 239000007789 gas Substances 0.000 claims description 18
- 239000001307 helium Substances 0.000 claims description 4
- 229910052734 helium Inorganic materials 0.000 claims description 4
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical group [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 4
- 239000006227 byproduct Substances 0.000 claims description 3
- 238000004611 spectroscopical analysis Methods 0.000 claims description 2
- 239000000284 extract Substances 0.000 claims 1
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 230000037353 metabolic pathway Effects 0.000 description 1
- 230000037323 metabolic rate Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/04—Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components
- H01J49/0431—Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components for liquid samples
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/18—Water
- G01N33/1806—Biological oxygen demand [BOD] or chemical oxygen demand [COD]
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Food Science & Technology (AREA)
- Molecular Biology (AREA)
- Emergency Medicine (AREA)
- Biomedical Technology (AREA)
- Medicinal Chemistry (AREA)
- Physics & Mathematics (AREA)
- Biodiversity & Conservation Biology (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
A water sample and gaseous carrier are fed to an oxygen liberating reactive material e.g. a bed of cobalt trifluoride. The carrier gas containing the liberated oxygen is then supplied at a controlled rate to a spectrometer for oxygen isotope analysis. Rapid repeat analysis can be carried out, typically once every 100 seconds.
Description
ISOTOPIC ANALYSTS OF WATER
This invention relates to methods of and apparatus for the oxygen isotopic analysis of water.
Currently, water samples are customarily analysed by exchange methods which can take 24 hours for acquisition of the necessary data. A further disadvantage of the exchange method is that the size of the water sample required for the analysis is relatively large.
It is one object of the present invention to provide a method of and apparatus for the oxygen isotopic analysis of water by means of which rapid repeat analyses can be performed, for example as rapidly as once every 100 seconds.
A further object of the present invention is to provide a method of and apparatus for the oxygen isotopic analysis of water in which the sample size required for the analysis is substantially smaller than is required for an exchange method, typically 1000 times smaller.
The method and apparatus according to the invention have many potential applications. These include for example the rapid monitoring of geological, hydrological and environmental samples. A further application is to the study of medical specimens, particularly those used in the determination of metabolic pathways and rates.
In order to carry out the oxygen isotopic analysis of water in accordance with the invention it is necessary to use a material which will liberate oxygen from the water sample.
Cobalt trifluoride (CoF3) is one compound which can be used to liberate oxygen from water under static reaction conditions and which is also readily adaptable to dynamic flow-through systems. Cobalt trifluoride is a compound which is very stable under normal laboratory conditions but which becomes reactive at elevated temperatures.
In accordance with one aspect of the present invention there is provided a method of carrying out an oxygen isotopic analysis of water, which comprises delivering a water sample and a gaseous carrier to an oxygen-liberating material to liberate oxygen from the water, and controlling the flow of the oxygen-carrying gas therefrom so that it is suitable for analysis by spectrometry.
The oxygen-liberating material is preferably cobalt trifluoride.
In one preferred embodiment, a stream of helium as carrier gas is passed through a bed of cobalt trifluoride at a temperature of the order of 350"C, and water samples of the order of 0.2y1 in size are delivered directly to the bed.
Preferably, the water samples are injected directly into the reagent in the bed.
In accordance with another aspect of the invention there is provided apparatus for the oxygen isotopic analysis of water, comprising a bed of material which is reactive to water to liberate oxygen therefrom, means for delivering samples of water to said bed, means for generating a stream of carrier gas and for directing said carrier gas over or through said bed, a spectrometer to which the oxygen-carrying gas from said bed is directed, and control means to adapt the flow of said oxygen-carrying gas to the spectrometer.
Preferably, the bed is of heated cobalt trifluoride.
A capillary device may be used to obtain a sample of the gas from the output side of the bed for onward transmission to the spectrometer.
One embodiment of a method and apparatus in accordance with the invention will now be described by way of example and with reference to the accompanying drawing which is a schematic illustration of the analysis system.
The method as illustrated in the drawing is based upon the use of a bed 10 of cobalt trifluoride. This bed may comprise for example 50mg of CoF3 contained within a nickel tube having a 4mm outside diameter. Means indicated by arrows 11 are provided to heat the bed 10. A stream of helium gas indicated at 12 is directed to flow through or over the bed 10 and an injector 13 is arranged to inject water samples directly onto the reagent CoF3 in the bed by means of a needle 14. The water samples can be 0.2p1 (200yg) for example. The cobalt trifluoride bed is heated to a temperature of the order of 350"C, at which temperature the CoF3 is reactive. It would alternatively be possible to inject the water samples into the helium gas stream, but injection directly onto the reagent is preferred.
After the gas leaves the bed 10 it is fed through a filter 15 containing potassium bromide (KBr) or sodium fluoride (NaF) to remove by-products containing fluorine. It then passes through a liquid nitrogen Dewar vessel, indicated generally at 16, which removes any traces of liquid from the sample.Then it is fed to a flow dividing device 17. The sample size referred to above provides oxygen from the water as a 70 second wide pulse. The flow of oxygen under such circumstances is too great to be handled by a mass spectrometer. Therefore, the flow dividing device, indicated generally at 17 and based upon a capillary splitting device, allows only a small proportion of the gas to be directed to a mass spectrometer 18, with the remaining gas passing to waste as indicated by arrow 20. The mass spectrometer 18 is therefore allowed to "sniff" the gas generated from each sample. An approximately 50:1 capillary split, i.e. of the order of 2%, has been found to be satisfactory.
With a water sample of 0. 281 as referred to above, the actual amount of 02 entering the mass spectrometer 18 is 1 x 10-8 mole, assuming quantitative yield. From this size of sample, values of 5170 = -0.1 + 0.25%o; 618 O = -0.2 i 0.2who have been obtained for SMOW (standard mean ocean water) run against a pure laboratory standard. A source of reference oxygen is indicated by the arrow 22 in the drawing, feeding into the mass spectrometer 18 via a split capillary device 23 which enables a small gas sample to be taken from the supply.
This oxygen sample is used for comparison purposes.
Because with the sample size from the bed 10 referred to above one obtains oxygen as a 70 second wide pulse, H20 samples can therefore be introduced by the injector 13 on a 100 second duty cycle, so that rapid repeat analyses can be performed. This is of very considerable benefit. Water samples differing by up to 60who can be run consecutively with only negligible memory effect on the first sample which follows a change of material.
Although the invention has been described above in terms of specific materials and specific operating parameters, these are given by way of example only. Variations in materials, sample sizes, temperatures, etc can be effected without exceeding the scope of the invention.
Claims (19)
1. A method of carrying out an oxygen isotopic analysis of water, which comprises delivering a water sample and a gaseous carrier to an oxygen-liberating material to liberate oxygen from the water, and controlling the flow of the oxygencarrying gas therefrom so that it is suitable for analysis by spectrometry.
2. A method as claimed in claim 1, in which the oxygenliberating material is cobalt trifluoride.
3. A method as claimed in claim 2, in which the cobalt trifluoride is heated to a temperature of the order of 350"C.
4. A method as claimed in any preceding claim, in which the gaseous carrier is arranged to flow over or through a bed of the oxygen-liberating material, and the water sample is delivered directly to the material in the bed.
5. A method as claimed in any of claims 1 to 4, in which the water sample is injected into the oxygen-liberating material.
6. A method as claimed in any preceding claim, in which the gaseous carrier is helium.
7. A method as claimed in any preceding claim, in which the oxygen-carrying gas is passed through filter means to remove by-products introduced by the oxygen-liberating material.
8. A method as claimed in any preceding claim, in which the samples are each of the order of 0.2y1 in size.
9. A method as claimed in any preceding claim, in which water samples are introduced at intervals of the order of 100 seconds.
10. A method as claimed in any preceding claim, in which of the order of 2W of the oxygen-carrying gas coming from the oxygen-liberating material is fed to a spectrometer for analysis.
11. A method of carrying out an oxygen isotopic analysis of water substantially as hereinbefore described with reference to the accompanying drawing.
12. Apparatus for the oxygen isotopic analysis of water, comprising a bed of material which is reactive to water to liberate oxygen therefrom, means for delivering samples of water to said bed, means for generating a stream of carrier gas and for directing said carrier gas over or through said bed, a spectrometer to which the oxygen-carrying gas from said bed is directed, and control means to adapt the flow of said oxygen-carrying gas to the spectrometer.
13. Apparatus as claimed in claim 12, in which the bed is of heated cobalt trifluoride.
14. Apparatus as claimed in claim 12 or 13, in which said water delivery means comprises a sample injector.
15. Apparatus as claimed in any of claims 12 to 14, in which said control means comprises a capillary device arranged to sample the gas from the output side of the bed.
16. Apparatus as claimed in any of claims 12 to 15, in which the capillary device extracts a sample which is approximately 2k of the gas at its input.
17. Apparatus as claimed in any of claims 12 to 16, which includes filter means at the output of the bed to remove byproducts introduced by the oxygen-liberating material.
18. Apparatus as claimed in any of claims 12 to 17, which includes means to provide reference samples of oxygen to the spectrometer.
19. Apparatus for the oxygen isotopic analysis of water, substantially as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9701901A GB2309782B (en) | 1996-02-03 | 1997-01-30 | Isotopic analysis of water |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9602209.0A GB9602209D0 (en) | 1996-02-03 | 1996-02-03 | Isotopic analysis of water |
| GB9701901A GB2309782B (en) | 1996-02-03 | 1997-01-30 | Isotopic analysis of water |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9701901D0 GB9701901D0 (en) | 1997-03-19 |
| GB2309782A true GB2309782A (en) | 1997-08-06 |
| GB2309782B GB2309782B (en) | 1999-05-19 |
Family
ID=26308598
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9701901A Expired - Fee Related GB2309782B (en) | 1996-02-03 | 1997-01-30 | Isotopic analysis of water |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2309782B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2389903A (en) * | 2002-04-16 | 2003-12-24 | Univ Bern | Providing a gaseous product for analysis |
| US7213443B2 (en) | 2002-04-16 | 2007-05-08 | University Of Bern | Process and apparatus for providing gas for isotopic ratio analysis |
| DE10256009B4 (en) * | 2002-04-16 | 2008-05-29 | Universitaet Bern | Method and apparatus for providing a gaseous substance for the analysis of chemical elements or compounds |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108593835A (en) * | 2018-06-28 | 2018-09-28 | 南京信息工程大学 | The assay method of the oxygen isotope ratio of nitrate granules object in a kind of atmospheric aerosol |
-
1997
- 1997-01-30 GB GB9701901A patent/GB2309782B/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2389903A (en) * | 2002-04-16 | 2003-12-24 | Univ Bern | Providing a gaseous product for analysis |
| GB2389903B (en) * | 2002-04-16 | 2006-06-07 | Univ Bern | Process and apparatus for providing a gaseous substance for the analysis of chemical elements or compounds |
| US7213443B2 (en) | 2002-04-16 | 2007-05-08 | University Of Bern | Process and apparatus for providing gas for isotopic ratio analysis |
| DE10256009B4 (en) * | 2002-04-16 | 2008-05-29 | Universitaet Bern | Method and apparatus for providing a gaseous substance for the analysis of chemical elements or compounds |
| US7985597B2 (en) | 2002-04-16 | 2011-07-26 | Universitat Bern | Process and apparatus for providing a gaseous substance for the analysis of chemical elements or compounds |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2309782B (en) | 1999-05-19 |
| GB9701901D0 (en) | 1997-03-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20010130 |