Rapid and quantitative extraction and analysis of trace organics using directly coupled SFE-GC

Supercritical fluid extraction can be coupled with capillary gas chromatography (SFE-GC) using commercially-available on-column or split/splitless injection ports. While liquid solvent extractions require several hours or even days to perform, SFC-GC analyses can be completed in ≤ 1 hour including extraction, analyte concentration, and GC separation. SFE-GC yields chromatographic peak shapes that compare favorably with those obtained using conventional liquid solvent injections. Quantitative extraction and recovery of analytes is usually achieved in 10 minutes, and maximum sensitivity is obtained since the extracted analytes can be quantitatively transferred into the GC column for cryogenic focusing prior to GC analysis. SFE-GC analysis of a variety of organic pollutants from environmental solids and sorbent resins, and flavor and fragrance compounds from food products will be discussed.     

Characterization of gasolines using on-line multidimensional supercritical fluid chromatography/ capillary gas chromatography

Summary Using packed column supercritical fluid chromatography on-line with capillary gas chromatography, gasolines have been characterized with respect to the separation of hydrocarbon classes as a group as well as a detailed fingerprinting of individual components within the classes. Using selective heartcutting, specific gasoline peaks were transferred to the capillary gas chromatograph as they eluted from the supercritical fluid chromatograph. Quantitative information was collected simultaneously from the flame ionization detectors that were used on both chromatographs. This report will describe the operational chromatographic conditions that were used for gasoline separations as well as provide results of quantitative heartcut reproducibility experiments of gasolines and hydrocarbon standards.

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Charakterisierung von Benzinen durch on-line-Kombination von multidimensionaler Chromatographie mit überkritischen fluiden Phasen und Capillar-Gas-Chromatographie

     

The use of alternative fluids in on-line supercritical fluid extraction – capillary gas chromatography

A key feature differentiating analytical supercritical fluid extraction (SFE) from conventional liquid extraction is the possibility of varying the solvent strength of a supercritical fluid to achieve selective extractions of specific target compounds, or functional classes of compound, from complex matrices. This can be accomplished by using supercritical fluids other than carbon dioxide, for example, sulfur hexafluoride, nitrous oxide, or sulfur hexafluoride-modified carbon dioxide. The use of these fluids will be demonstrated by the characterization of complex environmental and petroleum matrices by directly coupled SFE – capillary GC. On-line SFE-GC involves the decompression of pressurized extraction fluid directly into the heated, unmodified capillary split injection port of the chromatograph. This paper will also show how, by adjustment of the extraction temperature and pressure, SFE selectivity may be further enhanced.     

Solvent extraction of mercury using Alamine 304

Summary A study has been undertaken to develop a solvent extraction system for mercury using Alamine 304 in aqueous chloride medium. The parameters investigated included reagent concentration, acid concentration, pH, aqueous to organic phase ratio, and rate of extraction and stripping. The study shows that mercury can be extracted rapidly and efficiently from aqueous chloride solutions. A number of aqueous stripping reagents removed more than 90% of the mercury from the organic phase with only one equilibrium. These include HNO₃, NaOH and EDTA.

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Extraktion von Quecksilber mit Alamin 304

Zusammenfassung Die Extraktion von Quecksilber aus der wäßrigen Lösung des Chlorids mit Alamin 304 wurde untersucht. Die Konzentration des Reagens, der Säure, das pH, das Verhältnis der wäßrigen zur organischen Phase sowie das Extraktionsverhältnis wurden geprüft. Die Extraktion verläuft rasch und wirkungsvoll. Eine Reihe wäßriger Reagenzien entzieht mehr als 90% des Quecksilbers aus der organischen Phase. Dazu gehören Salpetersäure, Natronlauge und EDTA.

     

Gas chromatographic determination of gallopamil and norgallopamil in human plasma

A highly sensitive gas chromatographic assay is described for the simultaneous determination of gallopamil, a calcium channel blocking agent, and its major metabolite, norgallopamil. A multi-step extraction procedure is employed followed by on-column capillary gas chromatographic analysis using nitrogen-selective detection. Acetylation of norgallopamil is performed to enable accurate quantification of the metabolite. Linearity was achieved over the range 1-50 ng/ml for both analytes. Assay specificity, precision and accuracy were investigated.     

Determination of gallium by extraction and atomic absorption measurement

Summary Gallium can satisfactorily be determined by atomic absorption in organic solvents using air-acetylene or nitrous oxide-acetylene flame. It is recommandable to extract it as chloride complex. By employing MIBK and nitrous oxide-acetylene flame a considerable increase of absorption signal and sensitivity and elimination of the interference effect of a large number of metal ions was achieved.

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Bestimmung von Gallium durch Extraktion und Atomabsorptionsmessung

Zusammenfassung Mit Hilfe der Luft/Acetylen- oder N₂O/Acetylen-Flamme kann Ga aus organischen Lösungsmitteln mit guten Ergebnissen bestimmt werden. Zu bevorzugen ist die Extraktion als Chloridkomplex, Extraktion mit MIBK und Verwendung der N₂O-Acetylen-Flamme. So kann eine wesentliche Zunahme des Absorptionssignals, eine Verbesserung der Empfindlichkeit und Ausschaltung des störenden Einflusses zahlreicher Fremdionen bewirkt werden.

     

Quantitative determination of sub-ppb traces of polychlorinated compounds and pesticides in moss samples

Summary Two methods for the determination of organic polychlorinated compounds and pesticides in moss samples are described. The techniques are suited to determine sub-ppb concentrations. Different homogenisation and extraction methods are used followed by column chromatography clean-up. High-resolution gas chromatography combined with electron capture detection or negative-ion chemical ionization mass spectrometry is employed for quantification. Recovery results, blank values and a comparison of both methods are presented. The techniques have been successfully used for the analysis of moss samples collected from Middle Europe to the Subarctic.

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Quantitative Bestimmung von Sub-ppb-Spuren polychlorierter Verbindungen und Pesticide in Moosproben

Zusammenfassung Zwei Verfahren zur Bestimmung von polychlorierten organischen Verbindungen und Pesticiden in Moos werden beschrieben, die für den ppb-Bereich geeignet sind. Zur Homogenisierung und Extraktion dienen verschiedene Techniken, gefolgt von einem säulen-chromatographischen Clean-up. Zur Bestimmung dient die hochauflösende Gas-Chromatographie in Kombination mit Electron-capture-Detektion oder Massenspektrometrie durch chemische Ionisation mit negativen Ionen. Ein Vergleich beider Methoden wird gegeben sowie Wiederfindungsraten und Blindwerte für die verschiedenen Substanzen. Die Verfahren wurden erfolgreich auf Moosproben angewendet, die aus einem Gebiet von Mitteleuropa bis zur subarktischen Region gesammelt wurden.

     

Solvent extraction of tetravalent selenium

Summary A systematic study has been carried out on the extraction of SeI₄, by various water-immiscible organic solvents. Extraction has been investigated as a function of H₂SO₄ and KI concentrations. It has been found that the Se(IV) extraction is appreciably increased by addition of iodide ion to sulphuric acid solutions. In addition, the presence of water-miscible alcohols and acetone was found to enhance Se(IV) extraction from H₂SO₄-KI solutions. In the light of the obtained results an extraction mechanism is suggested.

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Untersuchungen zur Extraktion von vierwertigem Selen

Zusammenfassung Es wurde eine systematische Untersuchung zur Extraktion von SeI₄ mittels verschiedener mit Wasser nicht mischbarer organischer Lösungsmittel unternommen. Es wurde die Abhängigkeit der Extraktion von der Konzentration an H₂SO₄ und KI untersucht, wobei sich zeigte, daß die Se(IV)-Extraktion durch Zusatz von Iodid-Ionen zur schwefelsauren Lösung beträchtlich zu steigern ist. Weiters wurde gefunden, daß der Zusatz von wassermischbaren Alkoholen oder Aceton ebenfalls die Extraktion aus H₂SO₄-KI-Lösungen verbessert. Auf Basis dieser Resultate wird ein Extraktionsmechanismus vorgeschlagen.

     

Feasibility of on-line supercritical fluid extraction of steroids from aqueous-based matrices with analysis via gas chromatography-mass spectrometry

The solubility of testosterone, boldenone, androstenone, etiocholanolone, and epitestosterone are measured in pure supercritical CO2. Testosterone exhibited the highest solubility in supercritical CO2. The solubility of all steroids except epitestosterone increased by one order of magnitude with increasing pressure from 100 to 400 atm. Epitestosterone had the lowest solubility in supercritical CO2 and its solubility was not affected by pressure. The extraction efficiency of steroids from an aqueous saline environment exceeded 95%. Because of the partial solubility of water in supercritical CO2, the addition of a moisture trap after the aqueous vessel is necessary to prevent the plugging and deterioration of the gas chromatographic (GC) column. It is demonstrated that on-line supercritical fluid extraction-GC-mass spectrometry is feasible for the quantitative extraction and analysis of steroids from both saline and urine solutions. However, it is determined that the adsorbent vessel filled with Hydromatrix is not sufficient to trap all the moisture, and after 3 to 4 extractions, the GC column efficiency lowered.     

Direct continuous supercritical fluid extraction as a novel method of wine analysis. Comparison with conventional indirect extraction and implications for wine variety identification

Direct supercritical fluid extraction (SFE) of wines with carbon dioxide was compared to SFE of the sorbent used for solid-phase extraction of the same wine samples (SPE-SFE). Compared to SPE-SFE, the direct SFE results in amore specific and representative gas chromatographic fingerprint of the wine sample. The multivariate statistical processing of the direct SFE-GC data provides a clear-cut and sharp discrimination among the individual wine varieties while the discrimination based on the SPE-SFE-GC data is relatively poor. This finding reflects the adverse effects of additional analyte-sorbent interactions and sorption/desorption steps involved in SPE-SFE.     

Some tendencies of the synergistic extraction of lanthanides with mixtures of thenoyltrifluoroacetone and trioctylamine

Solvent extraction of Pr, Gd and Yb with mixtures of HTTA andTOA has been investigated. The values of the synergistic equilibrium constant have been calculated. Some tendencies of the synergistic extraction of lanthanides have been discussed.

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Einige Tendenzen in der synergistischen Extraktion von Lanthaniden mit einer Mischung aus Thenoyltrifluoraceton und Trioctylamin (Kurze Mitteilung)

Zusammenfassung Es wurde die synergistische Extraktion von Pr, Gd und Yb mit einer Mischung aus HTTA undTOA untersucht. Die synergistishcen Gleichgewichtskonstanten wurden berechnet und die Auswirkungen spezifischer Versuchsbedingungen auf das Extraktionsgleichgewicht diskutiert.

     

Apparatur zur automatischen quantitativen Extraktion von Wirkstoffen aus Arzneiformen

Zusammenfassung Es wird eine Apparatur zur schnellen quantitativen Extraktion von Wirkstoffen aus Arzneiformen beschrieben. In dieser Apparatur laufen alle für die Extraktion erforderlichen ArbeitsvorgÄnge, wie Extraktionsmittelzugabe, Rühren, ErwÄrmen, Abkühlen und Filtrieren, mittels eines elektronischen SteuergerÄtes vollautomatisch ab. Die Extraktionsdauer wird gegenüber der bisher verwendeten Methode wesentlich verkürzt. Die Eignung dieser Apparatur in der Arneimittelanalytik wird am Beispiel der Extraktion von Wirkstoffen aus zwei Emulsionen aufgezeigt.

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Apparatus for the automatic quantitative extraction of active ingredients from pharmaceutical preparations

An apparatus for rapid, quantitative extractions is described. In this apparatus all operations required for extraction, such as addition of extracting agent, stirring, heating, cooling, and filtration are fully automatic and are controlled by an electronic device. By comparison with the method employed hitherto the extraction time is considerably reduced. The utility of the apparatus in drug analysis is illustrated for the extraction of active ingredients from two emulsions.

     

Optimization of supercritical fluid extraction of volatile constituents from a model plant matrix

-Cellulose has been used as a model plant matrix to investigate the conditions required to optimize the supercritical fluid extraction of typical plant constituents, limonene, caryophyllene, carvone, eugenol and santonin, using carbon dioxide as the extraction medium. The conditions required for the successful recovery of the analytes were monitored by gas-liquid chromatography. Timed recovery studies enabled differences in the rates of extraction to be determined to ensure that sufficiently long extraction runs were used. Subcritical and supercritical extractions over the ranges −10 to 80°C and 50–250 bar were examined and 250 bar and 40°C were chosen as the optimum conditions. The effects of the addition of modifiers to the supercritical fluid were also examined. The work also demonstrated that increased selectivity for polar analytes such as lactones could be obtained by trapping the extract on a silica column coupled with selective elution.     

Analysis of organic pollutants in sewage by supercritical fluid extraction

Summary Analytical methods have been developed for the determination of organic pollutants of intermediate polarity in sewage. Water samples are first passed through a solid phase adsorption cartridge. The analytes are then extracted from the absorbent with supercritical CO₂ into a small volume of trapping solvent. Finally, the extracts are analyzed directly by capillary gas chromatography and gas chromatography-mass spectrometer. The various parameters (pressure, temperature, type and concentration of modifiers, trapping solvent, flow rate and volume of supercritical fluid and equilibrium time) influencing the efficiency of extraction were studied. Extraction efficiencies for the test compounds are >70%, and relative standard deviations are <4.6% (n=3). The methods established were applied to the analysis of sewage at the Lanzhou Wastewater Treatment Plant, China. 66 organic pollutants were detected, of which 15 compounds appeared in the list of priority pollutants suggested by the US EPA.     

Selektive Extraktion von Tellur mit Di-n-oktylsulfoxid

Zusammenfassung Über die Ergebnisse der Extraktion von Tellur und Selen aus stark salzsauren Lösungen mit Tri-n-butylphosphat, Tri-n-oktylphosphinoxid, Dibenzylsulfoxid und Di-n-oktylsulfoxid wurde berichtet. Von diesen stark solvatisierenden Reagenzien ist das Di-n-oktylsulfoxid zur Extraktion von Te(IV) und dessen Trennung von Se(IV) sowie von vielen anderen Elementen am besten geeignet. Eine Vorextraktion mit Diisopropyläther und der Einsatz von Fluorid als Maskierungsmittel ergeben in Kombination mit der Extraktion durch Di-n-oktylsulfoxid einen sehr selektiven Trenngang zur Anreicherung von Tellur durch Extraktion aus stark salzsaurer Lösung.

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Selective extraction of tellurium with Di-n-octylsulfoxide

Summary The results of extraction of tellurium and selenium from strong hydrochloric acid solutions with tri-n-butylphosphate, tri-n-octylphosphineoxide, dibenzylsulfoxide and di-n-octylsulfoxide were reported. Of these highly solvatizing reagents, di-n-octylsulfoxide is most suitable for extraction of Te(IV) and its separation from Se(IV) as well as from many other elements. A pre-extraction with di-isopropyl ether and the use of fluoride as masking agent give rise to a highly selective separation for enrichment of tellurium by extraction from a strong hydrochloric acid solution in combination with extraction by di-n-octylsulfoxide.

     

The separation of In,Sn, and Sb by liquid-liquid extraction

Summary The extraction behaviour of In, Sn and Sb in HI and HCl media has been investigated and several separation procedures have been developed. Removal of Sb(V) from Sn(IV) is accomplished by extraction of Sb(V) from 7M HCl solution with isoamylacetate. Selective removal of Sn(IV) or In(III), or both, from Sb(V) is effected by extraction with benzene or isopropylether from HI solutions. The extractions are quite simple, rapid and efficient and therefore useful in the study of short-lived fission products.

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Zusammenfassung Das Verhalten von In, Sn und Sb bei Extraktion aus Jodwasserstoffsaurem bzw. salzsaurem Milieu wurde untersucht und einzelne Trennungsverfahren ausgearbeitet. Die Trennung von Sb(V) und Sn(IV) erfolgt durch Extraktion des Antimons aus 7-m Salzsäure mit Isoamylacetat. Die selektive oder gemeinsame Trennung der Ionen Sn(IV) und In(III) von Sb(V) gelingt durch Extraktion mit Benzol oder Isopropyläther aus jodwasserstoffsaurer Lösung. Diese Extraktionen sind einfach, rasch durchführbar und wirksam und daher geeignet für die Untersuchung kurzlebiger Spaltprodukte.

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Résumé On a étudié le comportement vis-à-vis de l'extraction de In, Sn et Sb dans les milieux HI et HCl et l'on a développé plusieurs procédés de séparation. On a réalisé la séparation de Sb(V) d'avec Sn(IV) par extraction de Sb(V) par l'acétate d'isoamyle à partir d'une solution HCl 7M. On a effectué la séparation sélective de Sn(IV) ou de In(III), ou des deux, d'avec Sb(V), par extraction par le benzène ou l'éther isopropylique à partir des solutions HI. Les extractions sont très simples, rapides et efficaces, et par conséquent d'une grande utilité dans l'étude des produits de fission à courte durée de vie.

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On leave from Natron Maglaj-Yugoslavia. This author wishes to acknowledge his gratitude to the C. E. N., Mol-Donk, for having made possible this radiochemical study.     

Supercritical fluid extraction / capillary supercritical fluid chromatography / Fourier transform infrared microspectrometry of polycyclic aromatic compounds in a coal tar pitch

The combination of supercritical fluid extraction, high resolution capillary supercritical fluid chromatography, and Fourier transform infrared microspectrometry is described for the separation and identification of polycyclic aromatic hydrocarbons in a coal tar pitch. The variable solvating power of the supercritical fluid was utilized to selectively fractionate the sample. The fluid extract was decompressed through a frit restrictor into the sample cavity of a cooled microvalve injector, where the analytes were deposited and concentrated for subsequent chromatographic analysis. Several of the analytes separated in the chromatograph were collected on a potassium bromide disc at a solvent elimination inter-face for subsequent infrared analysis involving the use of an infra-red microscope accessory. The spectra obtained show the power of this detection technique for distinguishing between isomers.     

Universal 5-min on-line method for extracting and isolating pesticide residues and industrial chemicals

Summary A new method for the extraction of pesticide residues and industrial chemicals with acetone is discussed. The extraction and partition steps are combined into one step by saturating the extraction solvent with NaCl and simultaneously driving away the water by dichloromethane. The organic phase, the volume of which is now independent of the original water content, is further dried with Na₂SO₄ and evaporated for GC- and LC-analysis.

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Universelle 5-Min-On-Line-Methode zur Extraktion und Isolierung von Pesticidrückständen und Industriechemikalien

Zusammenfassung Eine neue Methode zur Extraktion von Pesticidrückständen und Industriechemikalien wird beschrieben. Die Extraktion mit Aceton, die Verteilung dieser Verbindungen in die wässerige organische Phase durch Natriumchlorid und das Entfernen des Wassers aus der wässerigen organischen Phase durch Dichlormethan erfolgen in einem Schritt. Die organische Phase, deren Volumen nun vom Wassergehalt der Probe unabhängig ist, wird mit Na₂SO₄ getrocknet und zur GC- und LC-Analyse eingeengt.

     

Extraction and separation of bismuth(III) from steel and bismuth-base alloys

Summary Separation of bismuth(III) from iron(III), molybdenum(VI), vanadium(V), chromium(VI), titanium(IV), antimony(III), lead(II), beryllium(II), uranium(VI), hafnium(IV), indium(III) and zirconium (IV) is achieved by solvent extraction with high molecular weight amines from sodium succinate solution adjusted to suitable pH. Bismuth(III) is stripped from the organic phase and determined spectrophotometrically. The method is shown to be applicable to bismuth alloys.

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Extraktion und Trennung von Wismut(III) aus Stahl und wismuthältigen Legierungen

Zusammenfassung Wismut(III) läßt sich von Fe(III), Mo(VI), V(V), Cr(VI), Ti(IV), Sb(III), Pb(II), Be(II), U(VI), Hf(IV), In(III) und Zr(IV) durch Extraktion mit hochmolekularen Aminen aus Natriumsuccinat bei geeignetem pH trennen. Bi(III) wird dann von der organischen Phase getrennt und spektralphotometrisch bestimmt. Das Verfahren eignet sich für Wismutlegierungen.

     

Fluorometric determination of non-fluorescent amines by ion-pair extraction

Summary An ion pair extraction method is described for quantitative fluorometric determination in the ng/ml range of non-fluorescent amines used as drugs. As counter ion, reagent, anthracene-2-sulphonate was used. Its extracting ability of ion pairs with amines was studied by determination of extraction constants and its fluorescence properties by determination of quantum yield of fluorescence. The properties of a suitable organic solvent is discussed and methylene chloride was found to be advantageous. Conditions for quantitative extraction and determination are given and the method was applied to determination of amitriptyline in the range 10–100 ng/ml giving an extraction degree of 100% and a precision of 5%.

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Fluorimetrische Bestimmung nicht fluorescierender Amine durch Ionenpaarextraktion

Zusammenfassung Die untersuchten Amine finden Verwendung als Arzneimittel und können in Mengen von ng/ml bestimmt werden. Anthracen-2-sulfonat dient als Gegenion. Die Eignung zur Ionenpaarextraktion wird durch Bestimmung der Extraktionskonstanten geprüft. Die Fluorescenzeigenschaften werden durch Messung der Quantenausbeuten der Fluorescenz bestimmt. Die erforderlichen Eigenschaften eines Lösungsmittels werden diskutiert. Methylenchlorid erweist sich dabei als gut geeignet. Die Bedingungen für quantitative Extraktion und Bestimmung werden angegeben. Die Methode wurde für die Bestimmung von Amitriptyline im Bereich 10–100 ng/ml ausgearbeitet, wobei sich ein Extraktionsgrad von 100% und eine Präzision von 5% ergaben.