EP0815426A2 - Ameliorations se rapportant a la preparation d'echantillons destines a une analyse palynologique - Google Patents

Ameliorations se rapportant a la preparation d'echantillons destines a une analyse palynologique

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Publication number
EP0815426A2
EP0815426A2 EP96904813A EP96904813A EP0815426A2 EP 0815426 A2 EP0815426 A2 EP 0815426A2 EP 96904813 A EP96904813 A EP 96904813A EP 96904813 A EP96904813 A EP 96904813A EP 0815426 A2 EP0815426 A2 EP 0815426A2
Authority
EP
European Patent Office
Prior art keywords
sample
hydrofluoric acid
reaction medium
acid
digestion
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.)
Withdrawn
Application number
EP96904813A
Other languages
German (de)
English (en)
Inventor
Rae Anthony Jones
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Sheffield
Original Assignee
University of Sheffield
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from GBGB9502913.8A external-priority patent/GB9502913D0/en
Application filed by University of Sheffield filed Critical University of Sheffield
Publication of EP0815426A2 publication Critical patent/EP0815426A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/60—Compositions for stimulating production by acting on the underground formation
    • C09K8/62—Compositions for forming crevices or fractures
    • C09K8/72—Eroding chemicals, e.g. acids
    • C09K8/74—Eroding chemicals, e.g. acids combined with additives added for specific purposes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/44—Sample treatment involving radiation, e.g. heat
    • 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

Definitions

  • This invention relates to the preparation of kerogen samples for palynological analysis.
  • siliclastic rock samples for palynology involves mainly dissolution of silicate and carbonate minerals followed by preparative treatment of the organic residue or kerogen, for example, for microscopic analysis.
  • Dissolution of silicates, achieved using hydrofluoric acid (HF) is a time-consuming, expensive and extremely hazardous part of this process requiring the use of protective clothing and ventilated laboratory space and stringent waste disposal control.
  • a further problem which arises in the conventional treatment process is the necessity to dilute the reaction medium after HF digestion, neutralise excess HF, and sieve the sample to remove any fines and/or insoluble fluorides. This provides a further time-consuming step which impedes the automation of the procedure.
  • a method for the preparation of kerogen for palynological analysis in which a kerogen-containing particulate rock sample is treated by HF digestion, which comprises adding an inhibitor which is soluble in the HF reaction medium and inhibits the formation of an insoluble non-reactive layer on the particles of the sample.
  • the inhibitor can be, for example, a metal salt having a cation that is soluble in hydrochloric acid, and in either hydrofluoric acid, or aqueous hydrofluoric acid, or both.
  • Suitable soluble metal salts include, for example, salts of Group I and Group II metals, and transition metals, more particularly salts of alkali metals such as, for example, sodium and lithium.
  • the anion of the metal salt is preferably a halogen anion and more preferably a fluoride.
  • Other anions which may be used include chloride, bromide, nitrate and sulphate.
  • the soluble metal cations interfere with the deposition of insoluble fluorides on the particles of the sample by disrupting the lattice formation and thereby exposing the surfaces of the particles to further HF digestion.
  • Excellent results have been obtained using sodium fluoride and sodium chloride, and these are the preferred inhibitors for use in the present invention.
  • the inhibitor may be a fluoroboric acid, for example, tetrafluoroboric acid HBF 4 , which may be used in addition to, or instead of, the soluble metal salt inhibitor.
  • fluoroboric acid for example, tetrafluoroboric acid HBF 4
  • HBF 4 tetrafluoroboric acid
  • the action of the fluoroboric acid is to form soluble complex fluoroborates, with, for example, calcium ions, and thereby interfering with the deposition of insoluble calcium fluoride on the particles of the sample.
  • the sample is washed, crushed and sieved to remove larger particles and small fines, leaving particles having an average diameter of from typically 1 to 3mm and preferably from about 0.71 to 1.70mm. This may optimise acid percolation and allow a larger surface area for acid attack.
  • the particles of the sample generally contain clasts (which may also contain palynomorphs) and palynomorphs held in a silicate/carbonate cement matrix of variable composition.
  • a soluble metal salt preferably sodium fluoride, or sodium chloride.
  • the sample is then treated with HC1, of concentration preferably up to approximately 35 - 40%, (in a preferred embodiment 37% is used) at a temperature of from 20°C up to the boiling point of the reaction medium for a time of from 1 to 60 minutes in order to break up the cement and release the clasts and the palynomorphs.
  • tetrafluoroboric acid HBF 4 may be used instead of hydrochloric acid in an amount of from, for example, 20 to 50% by weight, based on the weight of the sample.
  • the HBF 4 may also function as an inhibitor.
  • the sample is then preferably evaporated to reduce the volume so that further acid may be added, and in one embodiment it may be evaporated to near dryness, and subjected to HF digestion using hydrofluoric acid, for example, at a concentration of up to about 60% but preferably in the range 40-60%, at a temperature of from 20°C to 120°C and for a time of from 1 to 220 minutes.
  • hydrofluoric acid for example, at a concentration of up to about 60% but preferably in the range 40-60%, at a temperature of from 20°C to 120°C and for a time of from 1 to 220 minutes.
  • a selective oxidising agent to further aid the digestion of carbonate and silicate materials such as, for example, sodium permanganate.
  • the HF digestion is preferably carried out in a microwave heating apparatus.
  • a suitable pressurised system microwave oven is described in Ellin & McLean, Palynology, 18 (1994): 23-31, the entire disclosure of which is incorporated herein by reference for all purposes.
  • the reaction medium is preferably contained in a microwave transparent vessel and the microwaves are directed toward a lower part of the vessel, allowing a reflux action to take place in an upper part thereof.
  • a focused microwave system of this type operates at atmospheric pressure, thus eliminating the need for a pressure relief vessel to contain the reaction medium.
  • Suitable focused microwave heating systems are available from Prolabo and sold under the trade marks Microdigest 301 and Microdigest 401.
  • the heating may be carried out under reflux for about 5 to 120 minutes at about 10-99%, and preferably 10 to 40%, power of a 400 watt focused microwave heating apparatus.
  • the sample is situated at a position at which the focused microwave energy is greatest and, in a still further aspect of the invention, the sample is raised above the floor of the microwave transparent reaction vessel on a novel support.
  • the support may comprise a platform which may comprise a horizontal grating which has holes of a size sufficient to allow palynomorphs released from the sample to fall through.
  • the grating may, for example, be supported by a surrounding microwave transparent support member, for example, a hollow tube having a foot, or feet, adapted to rest on the floor of the reaction vessel, and a shoulder or projection by means of which the platform may be raised or lowered into the vessel.
  • the sample support may comprise a bag or container, having a permeable wall permitting ingress of the reaction medium and retention of the palynomorphs released from the sample.
  • Such a bag may comprise, for example, a flexible
  • sock formed from PTFE of mesh size 12 microns or less, preferably 10 microns or less, with a diameter of about
  • 40mm and length 50 to 150mm preferably about 90 to 100mm.
  • the bag may be formed from one piece of PTFE mesh folded to shape, but is preferably formed from two sheets of PTFE mesh cut to size and stitched, or preferably glued or welded around their edges.
  • the adhesive or welded joint is preferably able to withstand a temperature of at least 120°C.
  • the support is a container or capsule having a permeable wall, for example, a permeable-walled tube, such as, for example, a sintered PTFE tube.
  • the tube can, for example, have a permeable wall with a pore size of from 5 to 20 microns, preferably about 10 microns.
  • the bag or container may be supported, for example, by a support ring or lid secured to the top edge of the bag or container.
  • FIG. 1 and 2 of the accompanying Drawings show, in side elevation, partly in section, respectively a platform and a container, the latter being illustrated in position in a microwave vessel.
  • Figure 3 shows a side cross-sectional view of a reaction vessel, a sample support in the form of a sock or bag and a tube for providing gas flow near the sample suppor .
  • the platform illustrated generally at 1, comprises a horizontal grating 2 of 2mm thickness, having a plurality of vertically directed holes 3 of 0.5mm diameter therein.
  • the grating 2 is supported around its periphery by a tube 4, of length 6cm, internal diameter 29mm and wall thickness 6mm.
  • the tube 4 has a base 5 which rests on the floor of the reaction vessel and a shoulder 6 by which it can be raised or lowered into the vessel.
  • Both the grating 2 and the tube 4 are preferably made from a suitable microwave transparent material, for example, Teflon.
  • the sample In use, the sample is placed on the grating 2, and the reaction medium heated by focused microwaves. As the palynomorphs are released by the HF digestion, they fall through the holes 3 to the floor of the reaction vessel.
  • reaction medium may be diluted, neutralised, and the sample sieved and treated in accordance with further procedures as detailed below.
  • FIG. 2 there is shown diagrammatically the relevant portion of a microwave digestion apparatus, illustrated generally at 11, which comprises a digestion vessel 12, and a reflux head 13.
  • the digestion vessel 12 and reflux head 13 are connected by a tubular passage 14 which terminates in an opening 15 in the lid 16 of the vessel.
  • Passing through the passage 14 and into the vessel 12 are reagent feed tube 17, and exhaust tube 18, connected respectively to a reagent entry hole 19 and a reflux head component 20.
  • the reagent feed tube 17 is the smaller of the two tubes, and the exhaust tube 18 is the larger.
  • the reagent feed tube 17 passes through and supports the top location block 21 of the digestion capsule 22, the body of which comprises a permeable PTFE tube 23.
  • the tube 23 is formed from sintered PTFE and has an average pore size of 10 microns.
  • the sample 24 is placed in the capsule 22, and the focused microwaves applied. As the reaction proceeds the palynomorphs are released and retained in the tube 23. After HF digestion, the sample can be treated as described hereinafter.
  • AOM amorphous organic matter
  • AOM occurs in two forms, dispersed and clumped. Dispersed AOM can be simply removed by washing it through a suitable sized sieve, while clumped AOM cannot and often incorporates palynomorphs. In order to remove clumped AOM and release any palynomorphs which may be present, extended and frequently repeated treatment is usually required. This can take up to four days in some cases to obtain clean samples which can be identified using a microscope. The treatment is conventionally carried out using strong oxidising agents since oxidative treatment enables unwanted AOM to be selectively removed by virtue of the fact that the majority of AOM is more susceptible to oxidation than sporopollenin which forms the walls of many palynomorphs.
  • the kerogen liberated by HF digestion is treated by a method which involves subjecting the kerogen to microwave heating in the presence of a suitable reaction medium for a period of time sufficient to bleach the palynomorphs and/or to reduce the level of any unwanted kerogen present.
  • the reaction medium can, for example, comprise nitric acid, and can be an oxidising medium if the nitric acid is present in a strength of greater than 50% concentration.
  • a complexing agent can be added to the reaction medium to complex any free HF still present.
  • the complexing agent solution may then be used as the reaction medium or solvent for the subsequent treatment step with nitric acid, or with an oxidising agent, or both.
  • suitable complexing agents include boric acid H 3 BO 3 and aluminium chloride A1C1 3 .6H 2 0.
  • the complexing agent is added as a saturated or near saturated solution. In the case of boric acid, a 5% solution or greater is preferred.
  • the preferred complexing agent is, however, aluminium chloride, which has a higher solubility (greater than 25%) and can also dissolve insoluble fluorides.
  • the treated kerogen sample may be quenched, diluted with water, and neutralised, for example, with potassium hydroxide KOH, before being stained and mounted on microscope slides.
  • the steps can be as follows:
  • HC1 of strength up to 35% with, as an inhibitor, NaCl, NaF, and/or HBF 4 of strength up to 50%, is added to the sample, which has been manually sieved to give a particle diameter range of from 0.71mm to 1.70mm, and the reaction medium heated to an elevated temperature for a period of up to 60 minutes;
  • reaction medium is evaporated to near dryness; 3. Hydrofluoric acid at a concentration of up to 60% is added and the reaction medium heated at an elevated temperature for up to 120 minutes;
  • Nitric acid is added to give a nitric acid concentration in the reaction medium of 50% or greater, and the sample heated at an elevated temperature for a period of up to 30 minutes;
  • reaction medium is quenched, diluted with water and neutralised with 2% KOH;
  • All the above method steps can, and preferably are, carried out in a focused microwave heating system equipped with, for example, a carousel for handling a plurality of samples, and with automated reagent dispensing and handling equipment.
  • the microwave system can be enclosed in a suitable fume extraction enclosure thereby reducing the risk of exposure of the operator to the fumes or to the reagents involved in the procedure.
  • the invention is illustrated by the following Examples:
  • Carbonate rich bituminous mudstone (carboniferous in age) is scrubbed, crushed and sieved to a particle size of 0.71 to 1.70mm average diameter.
  • the sample is evaporated to near dryness at less than 60% power for 2 minutes.
  • Example 1 The procedure of Example 1 is repeated to prepare the sample for HF digestion, except that in this case only 5g of sample is required, and the digestion vessel of Figure 2 is used.
  • the insoluble palynomorphs still contained in the PTFE sock, are rinsed with water, removed and subjected to microscopic analysis.
  • the rocks to be tested are crushed and sieved to a particle size of l-3mm in diameter. Whilst samples of up to about 1cm in particle size can be examined, it may be preferable to restrict the average diameter to 0.71 to 1.7mm average diameter. Typically particles of this size are produced during drilling through rock for oil exploration at the required depth of most interest such that palynology can be used to determine the age. Sieving eliminates fines, optimises acid percolation and provides a large surface area for acid attack. The sample may be weighed prior to testing to four decimal places and analyzed under the microscope to determine how many polynomorphs per gram are present. The sample is pre-treated with HCl and an inhibitor such as NaCl and/or HBF 4 .
  • This may be carried out by: a) placing the sample in an acid-proof micron rated sieve mesh (eg 5-20 microns in size) tied with, for example, PTFE thread such as that seen in Figure 3; or b) placing the sample in a sample support such as those illustrated in Figures 1 or 2, for example, a sintered PTFE tube with a stopper.
  • an acid-proof micron rated sieve mesh eg 5-20 microns in size
  • PTFE thread such as that seen in Figure 3
  • a sample support such as those illustrated in Figures 1 or 2, for example, a sintered PTFE tube with a stopper.
  • a 5g rock sample which may contain from 100% quartz to 100% CaC0 3
  • 10ml to 50ml of HCl and/or HBF 4 are added.
  • 20ml of HCl or HBF 4 or a combination of 10ml of HCl and 10ml of HBF 4 are used in combination.
  • sufficient acid in the form of HCl or HBF 4 is provided to ensure substantial removal of C0 3 minerals (eg CaC0 3 , MgC0 3 , FeC0 3 ) . Though not essential, this is a preferred feature of the method of the invention.
  • HBF 4 forms a complex with the C0 3 minerals and retains them in solution for subsequent removal.
  • HBF 4 can be added first onto a sample and HCl acts as a buffer to prevent fluorides from precipitating out.
  • HCl acts as a buffer to prevent fluorides from precipitating out.
  • sufficient acid is provided such that, once the HCl/ HBF 4 , digestion has begun, the concentration of acid, whilst falling, is still sufficient to enable the reaction to be completed in a reasonable time.
  • 20ml of HCl and/or HBF 4 for 5g of rock will be sufficient.
  • Focused microwave heating will further reduce the reaction time and is typically provided for up to an hour.
  • the acid solution may be stirred by an air bubble stream as illustrated in Figure 3.
  • a digestion vessel 30 is provided.
  • a bag or sock 31 containing the sample is placed in vessel 30.
  • Bag 31 typically an acid-proof micron rated sieve mesh having a sieve dimension of 5-20 micrometres, is tied with a PTFE thread 32.
  • the reactive mixture 35 is stirred by a flow of air bubbles 34 which are introduced into the reaction medium towards the base of vessel 30 by tube 33.
  • the reagent medium 35 is mixed by the air flow 34, this also serves to disturb the contents of bag or sock 31 thus releasing fines from same into the surrounding reagent mixture.
  • the air flow is controlled and is relatively slow.
  • Excess acid mixture can be decanted from the tubes using a peristaltic pump, thus allowing for acid recycling.
  • the reaction vessel may be topped up with water and decanted to remove the unwanted Ca * ion or by the use of backwashing using the micromesh bag or sock to retain the sample whilst eliminating unwanted ions, which may be partially complexed following treatment with HBF 4 .
  • ions likely to precipitate with HF are removed in order to prepare the sample for treatment with HF.
  • the sample may be evaporated to reduce the volume and/or to near dryness by heating.
  • HCl typically of 37% concentration (or 12 molar) is added to the sample to solubilise the fluorides formed by HF treatment.
  • fluorides may be A1F 3 , NaF.
  • 5-50ml of HCl will be added along with 50ml to 95ml of HF to form approximately 100ml of HF digestion mixture.
  • HF typically of about 40-60% strength
  • about 25-100ml of HF may be added to digest any silicates present.
  • the salt NH 4 F may be added to the HF during the above process as this may increase the HF concentration upon heating.
  • a stream of air bubbles is substantially continuously flowed through the reaction vessel as described in the preceding paragraphs to facilitate mixing and further digestion of the sample.
  • the mixture is heated in a microwave under reflux for 5 - 120 mins at 10 - 99% power, and preferably 10 - 40% of power of 400w microwave focused in the lower 4cm of the microwave chamber.
  • the acid mixture is then decanted from the reaction vessel using a peristaltic pump. This again may allow for acid recycling.
  • the peristaltic pump may be adapted to accommodate, for example, 16 channels of acid removal at any one time. If the acid contains complexing agents such as HBF 4 then it may not be possible to recycle the acid mixture. Otherwise, the acid mixture may be mixed with fresh acid in the proportion 1:1 or 1:2 for later reuse.
  • the sample is then back-washed with warm water and, if the sample is not within a bag or sock 31 for backwashing within the sample, a holder having an acid resistant monofilament nylon sieve and running hot water may be used, though this is less preferred.
  • saturated boric acid H 3 B0 3 may be added at a concentration of 50g per litre at room temperature.
  • A1C1 3 .6H 2 0 may be added at a strength of 2 molar to complex the remaining HF and any insoluble fluorides. This acts in a molar proportion of 1:6 with respect to the HF.
  • Any other suitable complexing agent to partially or substantially neutralise or remove any HF remaining in the sample may be used. A small portion of the sample is checked under the microscope in the lab to determine whether the polynomorphs are free of amorphus organic matter (AOM), otherwise this can be removed by an oxidising agent as described in the previous examples.
  • AOM amorphus organic matter
  • the steps of a 'one shot process' include the following:
  • Fluoroboric acid in the form of 54% HBF 4 is added as an inhibitor and diluted with water. It is believed, though the invention is not limited to any particular theory, that the fluoroboric acid acts as an inhibitor by forming a complex with the calcium ions.
  • a tube such as tube 33 in Figure 3 is used to provide a gas flow, typically air, in a slow moving stream of air bubbles adjacent or below the rock sample.
  • Acetone is also added to the reaction mixture to subdue the formation of foam caused by the air flow. The mixture is heated for 5 minutes to 1 hour within a focused microwave heating apparatus until the carbonate reaction has subsided.
  • reaction mixture is then topped up with 10-15ml of HCl and 60ml of HF and subsequently heated for up to 2 hours within a microwave chamber to facilitate HF digestion.
  • the sample is washed, for example, by 800ml water over a 10-15 micron sieve, or otherwise treated for further analysis as hereinbefore described.
  • the method of the invention provides the basis for a simple and, in a preferred embodiment, almost fully automated process for preparing palynological sample in a relative quick and safe manner.

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  • Life Sciences & Earth Sciences (AREA)
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  • Medicinal Chemistry (AREA)
  • Remote Sensing (AREA)
  • Food Science & Technology (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
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  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
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Abstract

On décrit un procédé de préparation de kérogène destiné à une analyse palynologique, ce procédé consistant à traiter l'échantillon de roche particulaire contenant le kérogène à l'aide d'une digestion par l'acide fluorhydrique, laquelle comprend l'ajout d'un inhibiteur qui est soluble dans le milieu de réaction de l'acide fluorhydrique et inhibe la formation d'une couche de fluorure insoluble sur les particules de l'échantillon.
EP96904813A 1995-02-15 1996-02-15 Ameliorations se rapportant a la preparation d'echantillons destines a une analyse palynologique Withdrawn EP0815426A2 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB9502913 1995-02-15
GBGB9502913.8A GB9502913D0 (en) 1995-02-15 1995-02-15 Improvements in or relating to the preparation of samples for palynological analysis
GBGB9523328.4A GB9523328D0 (en) 1995-02-15 1995-11-15 Improvements in or relating to the preparation of samples for palynological analysis
GB9523328 1995-11-15
PCT/EP1996/000680 WO1996025652A2 (fr) 1995-02-15 1996-02-15 Ameliorations se rapportant a la preparation d'echantillons destines a une analyse palynologique

Publications (1)

Publication Number Publication Date
EP0815426A2 true EP0815426A2 (fr) 1998-01-07

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EP96904813A Withdrawn EP0815426A2 (fr) 1995-02-15 1996-02-15 Ameliorations se rapportant a la preparation d'echantillons destines a une analyse palynologique

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EP (1) EP0815426A2 (fr)
AU (1) AU4877996A (fr)
WO (1) WO1996025652A2 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2003599A (en) * 1997-12-23 1999-07-12 Cem Corporation Gas agitation of microwave assisted chemical processes
CN103063505A (zh) * 2012-06-04 2013-04-24 上海出入境检验检疫局工业品与原材料检测技术中心 一种低hf用量的汽车催化剂微波消解方法
CN103245553A (zh) * 2013-05-24 2013-08-14 中国热带农业科学院分析测试中心 酸回流积液式环保高效元素分析样品消解方法
US12385896B2 (en) * 2022-03-01 2025-08-12 Saudi Arabian Oil Company Transporting clastic rock samples for palynomorph analysis

Family Cites Families (7)

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Publication number Priority date Publication date Assignee Title
US2663689A (en) * 1950-12-26 1953-12-22 Independent Eastern Torpedo Co Well treating solution
US4304676A (en) * 1980-03-11 1981-12-08 Halliburton Company Methods and compositions for dissolving silicates in subterranean formations
US4753033A (en) * 1985-03-24 1988-06-28 Williams Technologies, Inc. Process for producing a clean hydrocarbon fuel from high calcium coal
US5135871A (en) * 1990-01-02 1992-08-04 Texaco Inc. Method for isolating kerogen from a mineral sample in a pressurized reaction cell
FR2673118B1 (fr) * 1991-02-27 1994-03-04 Prolabo Dispositif adaptable a un recipient, notamment pour reactions chimiques, reacteur comportant ledit dispositif et utilisation dudit reacteur.
DE4223116A1 (de) * 1992-04-30 1993-11-04 Mikrowellen Labor Systeme Vorrichtung zur verdampfungsbehandlung von vorzugsweise fluessigen stoffen, insbesondere reagenzstoffen, oder zum aufbereiten oder analysieren von probenmaterial
GB2286671B (en) * 1994-02-18 1997-08-06 Univ Sheffield Preparation of samples for kerogen analysis

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9625652A3 *

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WO1996025652A3 (fr) 1996-11-21
WO1996025652A2 (fr) 1996-08-22
AU4877996A (en) 1996-09-04

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