US3451545A - Method for separating micro-organisms from earth samples - Google Patents
Method for separating micro-organisms from earth samples Download PDFInfo
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- US3451545A US3451545A US653011A US3451545DA US3451545A US 3451545 A US3451545 A US 3451545A US 653011 A US653011 A US 653011A US 3451545D A US3451545D A US 3451545DA US 3451545 A US3451545 A US 3451545A
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- earth samples
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- 238000000034 method Methods 0.000 title description 21
- 244000005700 microbiome Species 0.000 title description 14
- 241001147665 Foraminifera Species 0.000 description 37
- 239000000243 solution Substances 0.000 description 23
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 22
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 21
- 150000003839 salts Chemical class 0.000 description 18
- 239000011248 coating agent Substances 0.000 description 12
- 238000000576 coating method Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 11
- 229910052742 iron Inorganic materials 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 8
- 238000005755 formation reaction Methods 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 8
- 239000002184 metal Substances 0.000 description 8
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 230000002378 acidificating effect Effects 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 6
- 238000000151 deposition Methods 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- OFOBLEOULBTSOW-UHFFFAOYSA-L Malonate Chemical compound [O-]C(=O)CC([O-])=O OFOBLEOULBTSOW-UHFFFAOYSA-L 0.000 description 4
- 150000007513 acids Chemical class 0.000 description 4
- 229910052783 alkali metal Inorganic materials 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- -1 etc. Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000007885 magnetic separation Methods 0.000 description 4
- 241000894007 species Species 0.000 description 4
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 239000003929 acidic solution Substances 0.000 description 3
- 150000001340 alkali metals Chemical class 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 239000000080 wetting agent Substances 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 150000003863 ammonium salts Chemical class 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- DIKBFYAXUHHXCS-UHFFFAOYSA-N bromoform Chemical compound BrC(Br)Br DIKBFYAXUHHXCS-UHFFFAOYSA-N 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 230000000536 complexating effect Effects 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 235000014413 iron hydroxide Nutrition 0.000 description 2
- 235000013980 iron oxide Nutrition 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 2
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical class [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 2
- 239000006148 magnetic separator Substances 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 2
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 235000015076 Shorea robusta Nutrition 0.000 description 1
- 244000166071 Shorea robusta Species 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 150000001413 amino acids Chemical class 0.000 description 1
- 239000000908 ammonium hydroxide Substances 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 229950005228 bromoform Drugs 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 235000015165 citric acid Nutrition 0.000 description 1
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid group Chemical class C(CC(O)(C(=O)O)CC(=O)O)(=O)O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229960004887 ferric hydroxide Drugs 0.000 description 1
- 229910001447 ferric ion Inorganic materials 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 150000002334 glycols Chemical class 0.000 description 1
- 150000001261 hydroxy acids Chemical class 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- 159000000014 iron salts Chemical group 0.000 description 1
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- BDJRBEYXGGNYIS-UHFFFAOYSA-N nonanedioic acid Chemical compound OC(=O)CCCCCCCC(O)=O BDJRBEYXGGNYIS-UHFFFAOYSA-N 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- G01N33/24—Earth materials
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
- E21B49/005—Testing the nature of borehole walls or the formation by using drilling mud or cutting data
Definitions
- the invention relates to an improved method for isolating micro-organisms such as foraminifera from earth samples; more particularly, it relates to an improved method for coating the foraminifera with magnetic material so that the foraminifera can be separated from the remaining earth samples by magnetic separating means.
- Micropaleontological analysis is an especial tool of the geologist by which he establishes stratigraphic correlations and maps subsurface structures. These analyses furnish information about the nature of the formations traversed, the quality of the fluids contained therein, their pressure, temperature and other bottom hole data. Such information is of great value in many phases of petroleum engineering-exploration, exploitation and reservoir operations.
- the paleontologist can determine the stratigraphical horizon of the scattered material.
- Micropaleontology is very largely concerned with the study of classification of foraminifera (or forams), microscopic one-celled organisms which have left their minute tests buried in the rocks as a record of their former existence. Their little shells are most likely to be found in muds, clays and shales, that is, in the finer sediments which were deposited in water that was not too violently agitated nor too swiftly flowing.
- Formations may sometimes be recognized and distinguished by a characteristic species, or more often by a particular assemblage of species, different from the species in other associated formations.
- forams are separated from earth sam- 3,451,545 Patented June 24, 1969 ples by treating the earth samples with a 2 to 5 percent solution of ferric chloride.
- a coating of an iron oxide hydrate is thus deposited on the foram samples. This coating, although extremely thin, is sufficient to allow magnetic separation of the coated foram samples by magnetic separation means.
- the ferric chloride solution is a relatively strong acidic solution that severely attacks the carbonate fossils and can damage the fragile foraminifera.
- the invention is an improvement in the method of soaking foraminifera obtained from earth formations, such as a well borehole, in ferric chloride solution to deposit magnetic iron compounds on the forams.
- the improved method herein disclosed rapidly deposits iron hydroxides on the carbonate shells of the forams while dissolving only very small amounts of carbonate.
- the improvement comprises contacting the forams with an aqueous solution containing a soluble salt of a complex of at least one magnetizable metal and a polyfunctional acidic material at a pH of incipient precipitation of hydrated oxides of the metal.
- a solution having a molar concentration of .1 mole of ferric salt and about .3 mole of malonic acid and neutralized to a pH of 5.5 to 6.0 was found to give the best results in terms of a relatively high iron deposition rate and a relatively low rate of carbonate dissolution.
- the present invention utilizes selected chelating materials that keep magnetizable metal ions, such as ferric ions, in solution as complexes in mildly acidic solutions that do not damage foraminifera.
- Earth samples containing micro-organisms as foraminifera are first obtained from an underground formation, as, for example, from a well borehole by substantially any sampling means, of Which many are known.
- the method of separating the forams from earth samples is accomplished by treating the earth samples with a solvent solution containing weak complexes resulting from the reaction of salts of elements susceptible to magnetization, e.g., Fe, Ni, Co, rare earths, etc., and a polyfunctional acidic compound capable of weakly complexing with the salt.
- the weak complexes become instable in the local increases in pH in the portions of the solutions in contact with the surfaces of the forams. This releases the magnetizable elements and causes magnetizable materials to be deposited on the forams.
- the samples thus treated are removed from the solution, Washed, and dried and the coated forams are separated from the remainder of the sample by suitable means such as magnetization.
- the earth samples are preferably first treated with a wetting agent, such as one or more alcohols, glycols, etc.
- a wetting agent such as one or more alcohols, glycols, etc.
- Useful magnetizable metal salts are iron, nickel, cobalt, rare earth, chloride, nitrate, sulfate, acetate, etc., as well as mixtures of one or more of such salts.
- the complexing polar compounds include polyfunctional acidic compounds of dibasic acids such as oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebasic acids;
- hydroxy acids e.g., hydroxy acetic, hydroxy propionic, hydroxy butyric, malic, tartaric, citric acids; amino acids and mixtures thereof.
- Particularly useful complexes result from the reaction in an aqueous medium of a ferric salt and malonic acid to which suflicient sodium hydroxide or other alkali metal or ammonium hydroxide is added to form an alkali metal salt of a ferric malonate complex.
- suflicient sodium hydroxide or other alkali metal or ammonium hydroxide is added to form an alkali metal salt of a ferric malonate complex.
- three parts of malonic acid are mixed with one part of an aqueous solution of a ferric salt. This ratio is preferred as giving optimum results; however, ratios in the range of one part ferric salt and two parts malonic acid to one part ferric salt and four parts malonic acid have been used with varying degrees of success.
- the pH of the aqueous solution containing the ferric malonate complex is adjusted, as, for example, by adding a sufl'lcient amount of a caustic alkali such as sodium hydroxide to the point of incipient precipitation of ferric hydroxide.
- a solution having a pH of 5.5 to 6. is preferably used to give the best results in terms of high iron deposition rate and low rate of carbonate dissolution.
- the concentration of the aqueous solution containing the ferric malonate complex is not critical since rapid deposition of iron salts occurs over a range of iron concentrations from .05 to 0.5 M. Solutions of high concentration, as, for example, .5 M FeCl with 1.5 M malonic acid, however, tend to float the foraminifera. A solution of about 0.1 molar concentration of iron is thus preferred with the pH of the .l molar concentration solution preferably maintained at least as high as 5.5 to minimize dissolution of the carbonate. The pH of the solution is also maintained below 6.0 to obtain rapid deposition of iron hydroxides on the foram samples.
- the pH at which initial precipitation of Fe(OH) occurs depends largely on the molar ratio of Fe/malonic acid, and only to a small extent on the actual concentration of the solution.
- the earth samples containing the foraminifera are contacted with the aqueous solution that contains a sodium salt of the ferric malonate complex by any known means.
- Foram-containing earth samples are preferably first wetted with a preferentially water-wetting agent, e.g., Cellosolve or alcohol, and then treated with a solution containing a complex of a magnetizable element, as noted above.
- a preferentially water-wetting agent e.g., Cellosolve or alcohol
- the Wetting agent prevents some forams" from floating on top of the solution and also aids in uniformly coating the forams with the magnetizable compound that is released from the complex.
- the earth samples are heated at approximately 80 C. for five to ten minutes, in order to produce a proper coating. After the forams have been coated, the earth samples are washed and dried, as, for example, by heating them at 110 to 120 C., and the dried earth samples are ready for magnetic separation.
- the coated forams can be removed from the dried earth sample by use of a strong magnetic field such as that used in a Frantz Iso-dynamic Magnetic Separator.
- a strong magnetic field such as that used in a Frantz Iso-dynamic Magnetic Separator.
- This reduction treatment does not damage the coated forams for examination by micropaleontologists for study under light microscopes, scanning electron microscopes, photographic means and the like.
- Magnetic separators which are well known in the art, are used to separate the coated foraminifera from the remainder of the earth samples. There is very little damage to the forams since the iron-containing complexes were dissolved in a mildly acidic solution that dissolves only insignificant amounts of carbonate from the forams.
- a solution having a molar ratio of iron to malonic acid of 1:3 is preferred; however, varying degrees of success have been obtained with molar ratios from 1:2 to 1:4 with iron molar concentrations from .1 to .4 grams and pH factors from 2.4 to 6.6.
- the mixtures of the forams and such a solution of a complex of at least one magnetizable metal and a polyfunctional acidic material are preferably heated at about C. for from about 2 to 10 minutes, although lower temperatures and longer times or higher temperatures and shorter times can be used.
- An improved method for coating micro-organisms disposed in earth samples with magnetic material so that the micro-organisms can be isolated by magnetic separating means comprising treating the earth samples containing micro-organisms in a solution containing a soluble salt of a complex of a magnetizable metal and a polyfunctional acidic material, the magnetizable metal being selected from the group consisting of iron, cobalt, nickel, and rare earths, the polyfunctional acidic material being a dibasic acid and the soluble salt being selected from the group consisting of alkali metal and ammonium salts.
- An improved method for coating micro-organisms disposed in earth samples with magnetic material so that the micro-organisms can be isolated by magnetic separating means comprising treating the earth samples containing micro-organisms in a solution containing a soluble salt of a complex of a magnetizable metal and a polyfunctional acidic material, the soluble salt being selected from the group consisting of alkali metal and ammonium salts and the complex being derived from the reaction of a ferric salt, malonic acid and an alkali hydroxide and the pH of the solution being between 5.5 and 6.0.
- the method of claim 2 including the step of establishing a molecular ratio of substantially one part of ferric salt to three parts of malonic acid.
- the method of claim 3 including the step of heating the samples with the complex solution at a temperature of approximately 80 C. for approximately 5 to 10 minutes to produce proper coating.
- the method of claim 4 including the step of pretreating the earth samples with a water-wettable agent.
- the method of claim 2 including the step of establishing a solution of approximately .1 moles of ferric salt to .3 mole of malonic acid.
- the method of claim 1 including the step of applying magnetic separating means to the earth samples for segregating the coated micro-organisms from the remainder of the earth samples.
- the method of claim 1 including the step of heating the coated micro-organisms at approximately 400 C. in the presence of hydrogen so as to convert the coating to magnetizable lower iron oxides.
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- Health & Medical Sciences (AREA)
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- Environmental & Geological Engineering (AREA)
- Mining & Mineral Resources (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Food Science & Technology (AREA)
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- Geochemistry & Mineralogy (AREA)
- Fluid Mechanics (AREA)
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Description
United States Patent 3,451,545 METHOD FOR SEPARATING MICRO-ORGANISMS FROM EARTH SAMPLES Heinz P. Studer, Bellaire, Tex., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed July 13, 1967, Ser. No. 653,011
Int. Cl. B03c 1/00; A01n 1/00; C23c 17/00 U.S. Cl. 209-8 9 Claims ABSTRACT OF THE DISCLOSURE A method for coating micro-organisms such as foraminifera in earth samples with a magnetizable compound by treating the foraminifera with an aqueous solution containing a soluble salt of a complex of a magnetizable metal and a polyfunctional acidic material and thereby depositing a magnetic compound on the foraminifera. The foraminifera can then be separated from the remaining earth samples by magnetic separating means.
BACKGROUND OF THE INVENTION Field of the invention The invention relates to an improved method for isolating micro-organisms such as foraminifera from earth samples; more particularly, it relates to an improved method for coating the foraminifera with magnetic material so that the foraminifera can be separated from the remaining earth samples by magnetic separating means.
Description of the prior art Micropaleontological analysis is an especial tool of the geologist by which he establishes stratigraphic correlations and maps subsurface structures. These analyses furnish information about the nature of the formations traversed, the quality of the fluids contained therein, their pressure, temperature and other bottom hole data. Such information is of great value in many phases of petroleum engineering-exploration, exploitation and reservoir operations.
By obtaining foraminifera samples from close and regular intervals from the earth, as, for example, from a well, so as to give as nearly a continuous stratigraphical sequence as possible, the paleontologist can determine the stratigraphical horizon of the scattered material. Micropaleontology is very largely concerned with the study of classification of foraminifera (or forams), microscopic one-celled organisms which have left their minute tests buried in the rocks as a record of their former existence. Their little shells are most likely to be found in muds, clays and shales, that is, in the finer sediments which were deposited in water that was not too violently agitated nor too swiftly flowing. Like all fossils, some species are found ranging through several or many geologic formations, whereas others are more narrowly limited. Formations may sometimes be recognized and distinguished by a characteristic species, or more often by a particular assemblage of species, different from the species in other associated formations.
It is very important to obtain foram samples that are as nearly perfect as possible. One of the most time-consuming operations in routine micropaleontology is the separation of microfossils from the washed residue of a sample of an earth formation. When hollow and filled with air, forams may be concentrated with heavy liquids, such as carbon tetrachloride or bromoform. Unfortunately, in most cases it has been necessary to pick out the forams by hand.
In one method, forams are separated from earth sam- 3,451,545 Patented June 24, 1969 ples by treating the earth samples with a 2 to 5 percent solution of ferric chloride. A coating of an iron oxide hydrate is thus deposited on the foram samples. This coating, although extremely thin, is sufficient to allow magnetic separation of the coated foram samples by magnetic separation means. However, the ferric chloride solution is a relatively strong acidic solution that severely attacks the carbonate fossils and can damage the fragile foraminifera.
SUMMARY OF THE INVENTION The invention is an improvement in the method of soaking foraminifera obtained from earth formations, such as a well borehole, in ferric chloride solution to deposit magnetic iron compounds on the forams. The improved method herein disclosed rapidly deposits iron hydroxides on the carbonate shells of the forams while dissolving only very small amounts of carbonate. The improvement comprises contacting the forams with an aqueous solution containing a soluble salt of a complex of at least one magnetizable metal and a polyfunctional acidic material at a pH of incipient precipitation of hydrated oxides of the metal. In a preferred embodiment, a solution having a molar concentration of .1 mole of ferric salt and about .3 mole of malonic acid and neutralized to a pH of 5.5 to 6.0 was found to give the best results in terms of a relatively high iron deposition rate and a relatively low rate of carbonate dissolution.
It is an object of this invention to enable large numbers of earth samples in diflicult paleontological problems, such as those arising in correlations in the Plio- Pleistocene formation of offshore Louisiana, to be easily and quickly handled.
It is a further object to materially simplify the separation of foraminifera from samples of bit cuttings from well boreholes.
DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention utilizes selected chelating materials that keep magnetizable metal ions, such as ferric ions, in solution as complexes in mildly acidic solutions that do not damage foraminifera. Earth samples containing micro-organisms as foraminifera are first obtained from an underground formation, as, for example, from a well borehole by substantially any sampling means, of Which many are known.
The method of separating the forams from earth samples is accomplished by treating the earth samples with a solvent solution containing weak complexes resulting from the reaction of salts of elements susceptible to magnetization, e.g., Fe, Ni, Co, rare earths, etc., and a polyfunctional acidic compound capable of weakly complexing with the salt. The weak complexes become instable in the local increases in pH in the portions of the solutions in contact with the surfaces of the forams. This releases the magnetizable elements and causes magnetizable materials to be deposited on the forams. The samples thus treated are removed from the solution, Washed, and dried and the coated forams are separated from the remainder of the sample by suitable means such as magnetization.
To prevent separation or losses due to the floating of the forams from the samples, the earth samples are preferably first treated with a wetting agent, such as one or more alcohols, glycols, etc.
Useful magnetizable metal salts are iron, nickel, cobalt, rare earth, chloride, nitrate, sulfate, acetate, etc., as well as mixtures of one or more of such salts. The complexing polar compounds include polyfunctional acidic compounds of dibasic acids such as oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebasic acids;
hydroxy acids, e.g., hydroxy acetic, hydroxy propionic, hydroxy butyric, malic, tartaric, citric acids; amino acids and mixtures thereof.
Particularly useful complexes result from the reaction in an aqueous medium of a ferric salt and malonic acid to which suflicient sodium hydroxide or other alkali metal or ammonium hydroxide is added to form an alkali metal salt of a ferric malonate complex. In a preferred embodiment, three parts of malonic acid are mixed with one part of an aqueous solution of a ferric salt. This ratio is preferred as giving optimum results; however, ratios in the range of one part ferric salt and two parts malonic acid to one part ferric salt and four parts malonic acid have been used with varying degrees of success. In each case, the pH of the aqueous solution containing the ferric malonate complex is adjusted, as, for example, by adding a sufl'lcient amount of a caustic alkali such as sodium hydroxide to the point of incipient precipitation of ferric hydroxide. A solution having a pH of 5.5 to 6. is preferably used to give the best results in terms of high iron deposition rate and low rate of carbonate dissolution.
The concentration of the aqueous solution containing the ferric malonate complex is not critical since rapid deposition of iron salts occurs over a range of iron concentrations from .05 to 0.5 M. Solutions of high concentration, as, for example, .5 M FeCl with 1.5 M malonic acid, however, tend to float the foraminifera. A solution of about 0.1 molar concentration of iron is thus preferred with the pH of the .l molar concentration solution preferably maintained at least as high as 5.5 to minimize dissolution of the carbonate. The pH of the solution is also maintained below 6.0 to obtain rapid deposition of iron hydroxides on the foram samples. Thus, the pH at which initial precipitation of Fe(OH) occurs depends largely on the molar ratio of Fe/malonic acid, and only to a small extent on the actual concentration of the solution. The earth samples containing the foraminifera are contacted with the aqueous solution that contains a sodium salt of the ferric malonate complex by any known means.
Foram-containing earth samples are preferably first wetted with a preferentially water-wetting agent, e.g., Cellosolve or alcohol, and then treated with a solution containing a complex of a magnetizable element, as noted above. The Wetting agent prevents some forams" from floating on top of the solution and also aids in uniformly coating the forams with the magnetizable compound that is released from the complex. The earth samples are heated at approximately 80 C. for five to ten minutes, in order to produce a proper coating. After the forams have been coated, the earth samples are washed and dried, as, for example, by heating them at 110 to 120 C., and the dried earth samples are ready for magnetic separation.
In the case of the above illustrative example, the coated forams can be removed from the dried earth sample by use of a strong magnetic field such as that used in a Frantz Iso-dynamic Magnetic Separator. However, it is preferable to subject the dried material to a reduction process by heating it at about 400 C. in the presence of hydrogen so as to convert the coating material to more readily magnetizable lower iron oxides and in this form magnetic separation techniques are more effective. This reduction treatment does not damage the coated forams for examination by micropaleontologists for study under light microscopes, scanning electron microscopes, photographic means and the like.
Magnetic separators, which are well known in the art, are used to separate the coated foraminifera from the remainder of the earth samples. There is very little damage to the forams since the iron-containing complexes were dissolved in a mildly acidic solution that dissolves only insignificant amounts of carbonate from the forams.
4 A solution having a molar ratio of iron to malonic acid of 1:3 is preferred; however, varying degrees of success have been obtained with molar ratios from 1:2 to 1:4 with iron molar concentrations from .1 to .4 grams and pH factors from 2.4 to 6.6. The mixtures of the forams and such a solution of a complex of at least one magnetizable metal and a polyfunctional acidic material are preferably heated at about C. for from about 2 to 10 minutes, although lower temperatures and longer times or higher temperatures and shorter times can be used.
I claim:
1. An improved method for coating micro-organisms disposed in earth samples with magnetic material so that the micro-organisms can be isolated by magnetic separating means, the method comprising treating the earth samples containing micro-organisms in a solution containing a soluble salt of a complex of a magnetizable metal and a polyfunctional acidic material, the magnetizable metal being selected from the group consisting of iron, cobalt, nickel, and rare earths, the polyfunctional acidic material being a dibasic acid and the soluble salt being selected from the group consisting of alkali metal and ammonium salts.
2. An improved method for coating micro-organisms disposed in earth samples with magnetic material so that the micro-organisms can be isolated by magnetic separating means, the method comprising treating the earth samples containing micro-organisms in a solution containing a soluble salt of a complex of a magnetizable metal and a polyfunctional acidic material, the soluble salt being selected from the group consisting of alkali metal and ammonium salts and the complex being derived from the reaction of a ferric salt, malonic acid and an alkali hydroxide and the pH of the solution being between 5.5 and 6.0.
3. The method of claim 2 including the step of establishing a molecular ratio of substantially one part of ferric salt to three parts of malonic acid.
4. The method of claim 3 including the step of heating the samples with the complex solution at a temperature of approximately 80 C. for approximately 5 to 10 minutes to produce proper coating.
5. The method of claim 4 including the step of pretreating the earth samples with a water-wettable agent.
6. The method of claim 2 including the step of establishing a solution of approximately .1 moles of ferric salt to .3 mole of malonic acid.
7. The method of claim 1 including the step of applying magnetic separating means to the earth samples for segregating the coated micro-organisms from the remainder of the earth samples.
8. The method of claim 2 including the steps of drying the coated earth samples and reducing the coating on the micro-organisms.
9. The method of claim 1 including the step of heating the coated micro-organisms at approximately 400 C. in the presence of hydrogen so as to convert the coating to magnetizable lower iron oxides.
References Cited UNITED STATES PATENTS 519,902 5/1-894 Barton 209-8 1,405,690 2/1922 Herr 209-8 2,460,188 1/ 1949 OKane 117-3 2,971,9 16 2/ 196 1 Schleicher.
HARRY B. THORNTON, Primary Examiner.
ROBERT HALPER, Assistant Examiner.
US. 01. X.R.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US65301167A | 1967-07-13 | 1967-07-13 |
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US3451545A true US3451545A (en) | 1969-06-24 |
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US653011A Expired - Lifetime US3451545A (en) | 1967-07-13 | 1967-07-13 | Method for separating micro-organisms from earth samples |
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Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
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US4070505A (en) * | 1974-03-04 | 1978-01-24 | The United States Of America As Represented By The Secretary Of Agriculture | Method of imparting paramagnetic susceptibility to cotton fibers |
US4219408A (en) * | 1978-04-27 | 1980-08-26 | Anglo-American Clays Corporation | Magnetic separation of minerals utilizing magnetic particulates |
US4225425A (en) * | 1975-10-01 | 1980-09-30 | Anglo-American Clays Corporation | Method for separating metallic minerals utilizing magnetic seeding |
US4225426A (en) * | 1975-10-01 | 1980-09-30 | Anglo-American Clays Corporation | Magnetic beneficiation of clays utilizing magnetic particulates |
US4738773A (en) * | 1985-06-22 | 1988-04-19 | Bayer Aktiengesellschaft | Separator for magnetic particles from liquid phase |
US4765486A (en) * | 1983-06-21 | 1988-08-23 | The United States Of America As Represented By The Secretary Of Agriculture | Method for obtaining a purified fraction from a mixture using a magnetic fluid |
US20080230158A1 (en) * | 2007-03-20 | 2008-09-25 | Michelle Romero | Systems and methods for customizing handbags |
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US519902A (en) * | 1894-05-15 | Process of refining iron | ||
US1405690A (en) * | 1920-12-03 | 1922-02-07 | Crawfordsville Seed Company | Seed-reclaiming process |
US2460188A (en) * | 1945-05-02 | 1949-01-25 | Commercial Solvents Corp | Fungicidal compositions |
US2971916A (en) * | 1957-01-30 | 1961-02-14 | Ncr Co | Microscopic capsules containing magnetizable material |
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Patent Citations (4)
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US519902A (en) * | 1894-05-15 | Process of refining iron | ||
US1405690A (en) * | 1920-12-03 | 1922-02-07 | Crawfordsville Seed Company | Seed-reclaiming process |
US2460188A (en) * | 1945-05-02 | 1949-01-25 | Commercial Solvents Corp | Fungicidal compositions |
US2971916A (en) * | 1957-01-30 | 1961-02-14 | Ncr Co | Microscopic capsules containing magnetizable material |
Cited By (20)
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US4070505A (en) * | 1974-03-04 | 1978-01-24 | The United States Of America As Represented By The Secretary Of Agriculture | Method of imparting paramagnetic susceptibility to cotton fibers |
US4225425A (en) * | 1975-10-01 | 1980-09-30 | Anglo-American Clays Corporation | Method for separating metallic minerals utilizing magnetic seeding |
US4225426A (en) * | 1975-10-01 | 1980-09-30 | Anglo-American Clays Corporation | Magnetic beneficiation of clays utilizing magnetic particulates |
US4219408A (en) * | 1978-04-27 | 1980-08-26 | Anglo-American Clays Corporation | Magnetic separation of minerals utilizing magnetic particulates |
US4765486A (en) * | 1983-06-21 | 1988-08-23 | The United States Of America As Represented By The Secretary Of Agriculture | Method for obtaining a purified fraction from a mixture using a magnetic fluid |
US4738773A (en) * | 1985-06-22 | 1988-04-19 | Bayer Aktiengesellschaft | Separator for magnetic particles from liquid phase |
US20080230158A1 (en) * | 2007-03-20 | 2008-09-25 | Michelle Romero | Systems and methods for customizing handbags |
US20100218863A1 (en) * | 2007-03-20 | 2010-09-02 | Miche Bag, Llc | Handbags with interchangeable covers and methods for customizing handbags |
US9198489B2 (en) | 2007-03-20 | 2015-12-01 | Miche Properties, Llc | Systems and methods for customizing handbags |
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