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gases are not needed to find their solubility. T h e method assumes the applicability of the Clausius-Clapeyron equation, Henry’s law, and the perfect gas laws. Eigenson and Ivchenko (11H) gave equations for the calculation of yields, viscosities, densities, and molecular weight of distillates based on the petroleum properties. Kajikawa et al. (31H) used a displacement chromatograph and mass spectrometer to analyze distillates for hydrocarbon types. A regression analysis of the data were then made and equations for estimating smoke point, aniline point, and specific gravity were derived. Gel permeation chromatography was used by Hodgin e t al. (26H) to obtain molecular weight distribution profiles of petroleum crudes, pitches, and asphaltenes; and Melikov (46H)described a method for determining the critical Reynolds number in the flow of liquids through porous rock strata. The flammabilities of aviation kerosene, gasolines, and other liquid fuels under simulated impact conditions was studied by Ford (13H). The fuel was atomized in a jet of moving air, contacted with an ignition source, and the duration and intensity of the resulting intermittent combustion was monitored with a light-sensitive device connected to a recording system. Ferrero and Panetti ( 1 2 H ) reported on the separation of olefins from paraffins and of linear branched olefins with macroreticular ion-exchange resins in silver (ion) form. Dynamic mass measurement of natural gas liquids under flowing conditions were made and reported by Templeton (72H). Peterman et al. (55H) reported a spectroscopic method for studying the adsorption of gas in liquid films. Kaerger (30H) reported on the interpretation and correlation of zeolitic diffusibilities obtained from nuclear magnetic resonance and sorption experiments, and Romavacek (59H) described a method for determining the volatility of pitch based on the diffusion of hydrocarbon vapors emanating from a large sample a t 200 OC through a small orifice into a stream of nitrogen; the response of a flame-ionization detector to the hydrocarbon was measured.
Hydrocarbons M. P. T. Bradley Spectra - Physics, Santa Clara, California
T h e analysis of hydrocarbons in petroleum fractions continues to follow the pattern established in previous years, with gas chromatography the most used technique, although the use of liquid chromatography, particularly for aromatic compounds, continues to grow rapidly. Review. A number of review articles covering various aspects of hydrocarbon analyses have appeared recently, ranging from the chromatography of hydrocarbons by Desty (590, through a review with 212 references on the analysis of commercial C, fractions by Schoellner et al. (2161). More eneral reviews, such as the review of petroleum hydrocarbons y Sanin (2030,on modern methods of analysis by Kalmutchi (1301), the analysis and testing of hydrocarbons, catalysts, pollution control, and products by Tomii and Futami (2660, are well supported by other reviews which are more directed in nature, such as that by Vercier and Cahuzac (2750, which is focused on the views of the French Refining industry, and those by Sauerland et al. (20511, Stadelhofer et al. (2471), Altgelt and Gouw ( 6 4 , and others (1261, 7721, 2001), who focused on polynuclear aromatics in heavy fractions. Reviews of the developments in mass spectroscopy by Nishishita (1650, in liquid chromatography by Thoms and Zander (261Z), and Matsuzaki (15411, and in gas chromatography by Takeuchi and Tsuge (256n. extensively cover petroleum hydrocarbon applications. Two publications of particular note for the quantitative aspects of hydrocarbon analyses are the ASTM manual on Hydrocarbon Analysis (81),and a publication by the National Bureau of Standards on Interlaboratory comparisons for trace level petroleum hydrocarbon determinations in marine sediments (1151). Novel Methods of Analysis. In such an established field as hydrocarbon analysis, the emergence of new and novel techniques is not frequent; however, some interesting developments have occurred. Sub-part-per-trillion analyses of
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polynuclear aromatics by means of a laser induced fluorescence technique (1951),and the work of Van Gee1 and Winefordner (2741), promise increasing laser applications, whereas the concentration technique developed by Twibell and Home (2711), has the benefit of simplifying an existing analysis technique. Masini et al. (153n,reported on the use of Stark modulated microwave analysis of czs-but-2-ene in but-1-ene with high accuracy. Thuemmel et al. (2641).applied multicomponent analysis with electron and 3 radiation. Zhukhovitskii et al. (2911) developed a technique they call chromadistillation, Coetzee et al. (471),applied anodic differential pulse voltametry to the analysis of polynuclear aromatics. Templeton (26.91), reported on the application of mass measurement techniques to natural gas liquids. and Annino et al. ( I O Z ) , described a totally pneumatic gas chromatograph. New detectors, particular those designed to give selectivity and specificity were reported for gas chromatographic systems (381,671, 1311, 1831) and liquid chromatography (1821). Petroleum Origins. The iise of C2-C7 hydrocarbons as indicaters for petroleum and natural gas was reported by Leythaeuser et al. (143Z);Faber, Stahl, and Carey (781)used isotope methods, in particular, the 13C/12Cratio to determine the origins and correlate and explore the boreholes during exploration. The analysis of steranes and triterpanes in a wide range of USSR crude oils was reported by Petrov, Pusti1’nikova et al. (1751). Petrov et al. (2741), and Orcova et al. ( I 701) also examined isoprenoid hydrocarbons. Shimanskii et al. extensively examined the Cs-Clo arenes from disperse organic matter in upper Jvrassic argillite (2290. The dispersed matter and petroleum from that region was similar in nature indicating that changes in composition were due to transformation of the dispersed organic material and not subsequent secondary processes in the petroleum deposits. Group Analysis. The analysis of petroleum hydrocarbns by functional group has always been important. An extension of the Bureau of Mines procedure to heavy tar sand bitumens was reported by Haines (1031), and a modification of the original procedure to shorten the analysis time was the subject of a publication by Sawatzky et al. (2071). Other group separations were reported (371,721, 1671.234I). Schulte et al. (2710,applied similar techniques to the analysis of coke oven effluents. Chemical Methods. Chemical methods are infrequently used for hydrocarbon analysis; however, methods were reported for the direct titration of olefines in propylene carbonate (1351);the colorimetric determinate of total aromatics in refinery and petrochemical waste streams (273I),based on reaction with formaldehyde and sulfuric acid. Wyganowski (2881)applied the technique of ion pairing to titrate unsaturated hydrocarbons with permanganate in nonaqueous media, and Gabriec-Koska et al. (97T)developed a colorimetric procedure for indene in naphthalene. Spectroscopic Techniques. A wide range of spectroscopic techniques have been applied to hydrocarbon analysis ranging from Ranian spectroscopy (931, 1 I ) , to photodissociation spectroscopy (70I). The most popular techniques are infrared and UV spectroscopy. Berthold et al. (241-261) continue their work on infrared structural group analysis methods. Corbett and Scullion (510 reported a simple statistical technique for the detection of specific minor impurities by IR. Egorova (720 used infrared to follow the oxidation of hydrocarbon mixtures. Proskuryakova et al. (1841) followed the selective absorption of components when petroleum filtered through clay minerals. Hellmann ( I 100 compared polycyclic compounds produced by biological and combustion processes. Improvements to the normal infrared procedures brought about by cooling (861) and Fourier transform techniques ( 2 5 In were also reported. Ultraciolet spectroscopic techniques range from the direct determination of aromatic compounds by UV absorption (1671, 1771. 1851) to second derivatiLe techniques (2081) to fluorescence systems with ITV excitation. Several authors (1111, 2671, 2821) used fluorescence to analyze polycyclic compounds in natural sediments. Hurtubise et al. (2221) characterized the fluorescence from shale oil. Heinrich and Guesten (1091) used the technique for the analysis of air borne polycyclic aromatic hydrocarbons. A low temperature technique using matrix isolation was applied to coal-derived liquids by Stroupe et al. (2.511). Schwartz and Wasik (2200 determined several polycyclic aromatics in water.
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They report that the method suffices for heavily polluted, deoxy enated water, b u t is not sensitive enough for grounfwater . Chemiluminescence was used for the analysis of reactive hydrocarbons by Van Heusden and Hoogeveen (1140 and by Fontijn and Ellison (830. Tuan Vo Dinh et al. (2700 studied the effect of heavy atom solvents on the phosphrescence of pyrene and phenanthrene. Luminscence spectroscopy was applied by Kirkbright e t al. (4111, 790 and D'Silva (690 and Tuan Vo Dinh (2691). Nuclear Magnetic Resonance. The use of NMR for hydrocarbon analyses appears to be shifting to carbon-13 systems. Surprenant and Reilley (2541) reported on the carbon-13 spectra of acyclic saturated hydrocarbons, whereas Sheshadri e t al. (2210 studied model hydroaromatic compounds. Shoolery and Budde (2310 used natural abundance carbon-13 to measure aromatics in crude oil. Hajek et al. (1040 applied Fourier transform techniques to the carbon-13 spectra to determine both aromatic and aliphatic carbon in crude oil residues. They report that the relative amounts are different from those determined by 'H NMR. Pugmire, Grant, et al. (1860 studied the spectra obtained from the hydrogenation of coal. Dorn and Wooton (6610 used both carbon-13 and 'H NMR with a reference material, 1,4-dioxane to obtain high precision for carbon-hydrogen ratio measurements. Ford and Friswell(840 determined the hydrogen content of aviation fuels by means of low resolution NMR. The method is rapid, and gives results that agree favorably with the ASTTM combustion method. Yamamoto e t al. (2891) used computer deconvoluting techniques to quantitatively analyze mixtures of olefinic compounds by proton N.M.R. Mass Spectroscopy. Meyerson (1564 reviewed the history of mass spectrometric analysis of organic compounds including correlations to the physical properties of petroleum fractions. Brodskii et al. (351) also focused on the physicochemical properties of petroleum fractions and their mass spectra. Young et al. (2900 used selected ion monitoring using both accelerating voltage and magnetic field variations. Gallegos (880 analyzed terpanes and steranes by means of metastable transition spectra. Shen and Bradley (2280 described a mass spectrometric inlet system usable for a very large range of samples from volatile liquids to polymers. Severin (2230 reported on a low voltage ionization for the analysis of nonvolatile hydrocarbon mixtures. Blumer (301) also used low voltage techniques in conjunction with probe distillation. Schiller (214Z) used low voltage methods for methylated polycyclic aromatics. Severin (2220 used photoionization a t 510.19 eV for the analysis of complex mixtures. Scheppele et al. (2120 and Karas et al. (1390 both applied field ionization and discussed the variations in sensitivity with structure. Sovob et al. (2551) compared the mass spectrometric degradation patterns of alkyl benzenes with those obtained by pyrolysis gas chromatography. Classical mass spectra determinations of known compounds were reported by Denisov e t al. (561-581) and Brodskii, Lukashenko, et al. (361). Quantitative aspects were covered by Jansky (1250 and Pfeifer et al. (1760,and Malinowski and McCue (1490, and Herzschuh e t al. (1131). The use of factor analysis for the classification of compounds was reported by Ritter et al. (1960 and Rozett et al. (1970. T h e popular technique of MS-GC was used by Albaigas et al. ( 2 0 to identify a series of C25to Cd0acyclic isoprenoids in crude oil. Tomi et al. (2651) applied the technique to the identification of cycloplentadiene and isoprene dimers and co-dimers. Hatch and Munson (1071) used reactant ion monitoring for selective detection in gas chromatography-mass spectroscopy. Other selective methods used were that by Iida and Shizuko (1221) who analyzed for trace impurities in benzene, and that by Hodges and Beauchamp (1180, who used lithium ions for chemical ionization. Spivakovskii et al. (2464 used GC-MS data t o calculate the Kovats indices of compounds from structural group information. Thin-Layer Chromatography. The dominant analysis technique for hydrocarbon analysis is undoubtedly the chromatographic separation systems. Thin-layer is the least used of these methods; however, particularly with fluorescing compounds, some interesting work has been published.
Shanfield et al. (2240 report that electrically activated gases can be used t o give fluorescence visualization of a variety of compounds. The determination of polycyclic aromatic compounds was reported by Candeli et al. (390,Jaraslov (854, Hornyak (1201), kogan and Gagarinov (1340, and Smeral (2361). The use of reversed phase TLC was reported by Shiraishi et al. (2300. Bergman et al. (210 impregnated silica plates with tetraalkylammonium salts, and Saxena and Bhattacharyya (2080 determined diolefines in olefinic cracked stocks by use of mercuric ion impregnated TLC plates, Saner and Fitzgerald (2011) applied TLC t o the analysis of water-borne petroleum oils. Liquid Chromatography. The use of liquid chromatography for the analysis of petroleum and coal products was discussed by Engelhardt (730. Bakalyar et al. (140 examined solvent selectively effects with particular emphasis on reversed phase systems. The effect of the mobile phase in adsorption chromatography was reviewed by Sasaki et al. (2040. Siouffi e t al. (2330 attempted to correlate the TLC separations of polycyclic aromatics with the LC separations. Hesse and Hagel (1120 used inclusion chromatography for the separation of substituted benzenes. Popl e t al. (1781) studied the influence of molecular structure on the adsorptivity of aromatic hydrocarbons on silica gel. Saner et al. (2020 used liquid chromatography for the identification of oil spill samples, whereas Whittle (2840 was concerned with the separation and quantitation of solvent red 24 and quinizarin markers in oil polluted waters. Vespalec (2760 studied the effects of liquid phase loading on modifed silica gels, Hansen et al. ( 6 3 0 used cation-exchange resins containing silver or copper for the separation of unsaturated compounds from liquid hydrocarbon mixtures. Lam and Grushka (1401) also used silver loaded columns to separate unsaturated geometric isomers. Wise et al. (2861) reported that chemically bonded aminosilane materials can be used for the normal phase separation of aliphatic and polycyclic aromatic hydrocarbons. Jahangir and Samuelson (1230 chromatographed aromatic compounds on sulfonated cation-exchange resins in aqueous media. Ordemann and Walton (1690 used ion-exchange resins with calcium and ferric ions as counter ions. Gvozdovich et al. (1011) demonstrated that a melamine polymer is usable for both gas and liquid separations of hydrocarbons. Goldstein (951) used cross-linked poly(vinylpyrro1idone) and polar solvents to separate aromatics by ring structure. The use of carbon modified silica gel was reported by Bebris et al. (170 and Colin and Guichon (481-501). Cowan (521) used a picric acid column to obtain 1,2,3,4tetrahydroanthracene free from other hydrogenation products. Alessi and Kikic ( 4 0 determined the partition coefficients of 20 hydrocarbons with both polar and nonpolar solvents. Jentoft and Gouw (1270 used Vydac reverse phase packing and carbon dioxide as mobile phase under supercritical conditions to quantitatively determine benzo[a]pyrene and benz[a]anthracene in automobile exhaust. Other authors who concentrated on the analysis of polycyclic aromatics in a variety of samples were Kaschani (1320, Thoms and Zander (2621),Berthold (231),Dong et al. (650, Boden (311),and Grant and Meiris (961). Methods for the analysis of heavy fractions were reported by several authors (181,341,681,811,2091,and 2150. Skinner and Smith (2350 reported that selective polycyclic aromatics can be analyzed rapidly in food grade mineral oils with close agreement to the FDA method. The use of liquid chromatography for the group separation of hydrocarbons was reported by Sautoni et al. (2521) for analytical systems and by the same group (2531) for preparative scale separations. Size exclusion systems were also applied to petroleum fractions by several authors (1161, 1171, 1601, 1641, 1791). Krishen and Tucker (1361) showed that n-alkanes, aromatic and cyclic aromatics, in the region 100-2000 molecular weight range can be separated by GPC. Popl e t al. (1801) studied the use of GPC materials for the reversed phase separation of aromatic hydrocarbons. A later publication (1814 suggested a method of predicting the retention indices of polysubstituted solutes. Gas Chromatography. The premier hydrocarbon analysis technique is still gas chromatography. In this year's review an interesting resurgance in gas-solid chromatography was noticed, particularly with surfaces modified with complexing
ANALYTICAL CHEMISTRY, VOL. 51, NO. 5, APRIL 1979
agents. In contrast, capillary chromatography has decreased, possibly because of the increasingly routine use of this technique. Gas-Solid Chromatography. Snowdon and Peake (2400 used inorganic salt eutectics for the analysis of environmental spill and petroleum geochemistry samples. Sawatzky, George, et al. (2061, 2071) used lithium chloride for high boiling petroleum distillates. Stepukhovich et al. (2491) used cobalt(I1) hydroxide for the separation of C1-C7 alkane, alkene mixtures. Wolf e t al. (2870 used modified porous glass for the separation of propane/propylene and similar mixtures. A comprehensive analytical procedure for saturated and unsaturated hydrocarbons was reported by Schulz (2181). Smolkova-Keulemansova (2381) used a urea-n-hexadecane clathrate for a variety of compounds that could be chromatographed below 90 OC. Acetylene black was compared to graphite by Li, Kim, and Kim (1440. DiCorcia and Samperi (600 reported separating 19 C4-C5 hydrocarbns on Carbopack C modified with 1,3,5-trinitrobenzene. Tanaka e t al. (2570 studied a series of vitreous carbons for the analysis of light hydrocarbons. The same authors also examined the precursors of these materials (2580. DiCorcia et al. (620 used 2,4,5,7-tetranitrofluorenone modified Carbon black for the separation of alkanes and alkenes. T h e separation of hydrocarbons on zeolites was reported by several authors (31, 1461, 1551). Allulli et al. (51) used synthetic inorganic ion-exchangers of the Zr(KP0,) type. Compleximetric Systems. The compleximetric separation of deuterated ethylenes by means of capillary chromatography on dicarbonyl[3-trifluoroacetylcamphoroto] Rhodium I was reported by Schurig (2191). Gavrilina et al. ( 9 2 n used cobalt phthalocyanines, whereas several authors concentrated on silver systems. Wasik and Brown (2831) used AgNO, supported on glass beads, Dautzenberg and Knoezinger (530 used tetraethylene glycol and naphthyl-1-acetonitrile to support the silver nitrate. Maier and Schriewer (1481) and Oelert e t al. (1681) preferred silver tetrafluoroborate. Norell and Gardner (1660 used silver trifluoromethanesulfonate. Galtieri and Crespi (891) used pyromellitic dianhydride to form charge transfer complexes with a variety of aromatic compounds, and for the determination of indane in naphtha solvents as in an identification of coal derived naphthas. Gas Chromatography Phases. Liquid crystal technology has been applied to chromatographic separations by Janini et al. (1240 and Vigalok et al. (2771). Kuchhal et al. (1371) worked with cyanoethylated polyols for the selective retention of aromatics. Stancher and Cerma (2481) compared poly(m-phenyl ether) and methyl silicones for the high temperature analysis of higher alkanes. Boksanyi and Kovats (321) introduced a synthetic CSi hydrocarbon phase. Banerjee et al. (150 evaluated 3-isoalkoxypropionitrilesfor the analysis of light hydrocarbons. Ravey (1920 preferred mixed bislactams. Ryba (1981) tabulated retention data for 70 hydrocarbons on dibutyltetrachlorophthalate. Martynyuk and Vigderguaz (1520 used colloid systems for the separation of both polar and nonpolar compounds. Lysyuk (1470 compared several phases for the resolution of polycyclic aromatic hydrocarbons. Kulikov e t al. (1381) synthesized a series of polyimides which were effective for hydrocarbon separation. Felscher and Sachse (821) compared several macroporous cross-linked copolymers. Millen and Hawkes (1591)studied the diffusion of linear alkanes in methyl silicone staticnary phases. Nabivach (1630 reported on the dependence of hydrocarbon retention parameters on the physicochemical properties of the supported stationary phase. Castello and D’Amato (401) correlated the retention volumes of a series of nonanes to the vapor pressure, activity coefficient, and structure of the compounds. Voorhees e t al. (2801) proposed the pyrolysis of dodecane or polyethylene for the generation of retention index standards. Kalashnikova et al. (2291) evaluated the thermodynamic significance of the Kovats indices of n-alkanes on carbon black. Dimov ( 6 4 a proposed an equation for the exact calculation of the retention indices of isoalkanes on squalane. Chre’tien and Dubois ( 4 6 0 reported the topological analysis of Kovats indices of an alkene sample analyzed on five different phases. Quantitation. Farrington e t al. (801) reported the intercalibration and analysis by three laboratories or petroleum
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hydrocarbons spiked in cod liver oil. Middleditch and Basile (1571) used deuterated analogues for the quantitation of environmental alkanes. Vitenberg et al. (2780 described a device for the injection of a gas in equilibrium with a liquid. Gaspar et al. (910 used a fluid logic gate for the injection of narrow sample plugs. Stolyarov (2501) described a modification of the internal normalization method for use with sample splitting. Environmental Analysis. Bartle, Lee. and Novtny (160 proposed an integrated method for the analysis of air pollutant polycyclic aromatic hydrocarbons. Black et al. (270 described a direct analysis method for nonreactive hydrocarbons in air. Cudney et al. (5311) described a rapid gas chromatographic method of analysis for C,-C, alkanes and alkenes in air. Esposito and Jacobs (771) concentrated on aromatic compounds, in particular those from solvents. Berry and Stein ( 2 2 0 focused on water soluble gasoline fractions, and used a radioisotopic standard for quantitation. Vitenberg et al. (2790 used an equilibrium vapor method for aromatics in water. Golden et al. (941) used solvent extraction to concentrate hydrocarbons prior to analysis. A similar procedure was used by Chaigneau and Chastagnier (431). Capillary Chromatography. Berezkin et al. (201) reviewed the use of packed capillary columns. Schieke and Pretorius (2130 described the separation of hydrocarbons on whisker-walled open tubular glass columns. Rang et al. (1901) reported the capillary gas chromatographic separation of C6-Cl,n-alkenes on polyphenyl ether. The same authors (1871-1890 also published a series of studies on n-alkynes, and monosubstituted cycloalkanes (1911). Engewald and Wennrich (751) determined the retention indices of a series of alkylbenzenes on several stationary phases. Sojak and his co-workers (2421-2451) also studied alkylbenzenes extensively. Kodama (1331) analyzed mixed alkylnaphthalenes used as encapsulating solvents in pressure sensitive copying paper. Tesarik et al. (2600 determined the optimum conditions for the gas chromatographic separation of naphthalene and biphenyl homologues. Oshima et al. (1714 determined monomethyl paraffins in n-paraffins. Block e t al. ( 2 8 0 developed methods for the analysis of hydrocarbon products from methanol conversion. Pankova et al. (1731) separated and identified bicyclic aromatic compounds in kerosine. Miscellaneous. Wilson (2851) reported on a unified scheme of analysis for the analysis of light petroleum products used as fire accelerants. Kajikawa et al. (1280 compared the relationship between the hydrocarbon composition and properties of several kerosines. Engewald et al. (741, 761) compared the molecular structure to chromatographic behavior of certain cycloalkanes. Greco (981) characterized ethylene feedstocks with microscale pyrolysis gas chromatography. Al-Thamir et al. ( 7 0 separated all the C1-C4 hydrocarbons by a combination of gas-solid-liquid chromatography. Complex esters of dian and hydrocinnamic acid were used for hydrocarbon analysis by Andreikova et al. ( 9 0 . Anosova ( 2 2 0 determined propane in turbine oil. Berezkin et al. (190 separated cyclic hydrocarbons with a squalane-carbon black system. Coal-carbonization by-products were analyzed (331) as were some pyrolysis tars (120. Funk (871) used inverse phase chromatography for the characterization of tar sand asphaltenes. Chizhkov et al. (440 used circulation chromatography in water vapor for the separation of isomeric pairs. Choubey et al. ( 4 5 0 described the elution behavior on unsaturated hydrocarbons. Deaconeasa e t al. (551) determined polycyclic aromatics with and without hetero atoms. Grenier-Loustalot et al. (991)studied the influence of conformations and structures on the retention volumes of cycloalkanes. Two-stage chromatography was used by Shefter and his co-workers (2261,2270. Telles et al. (2590 reported the composition of heavy aromatic fractions from the Minatatlan (Mexico) Refinery. Ashumov et al. (131) determined the hydrocarbon composition of some medical petroleum fractions. Langmaack and Sucker (1411) also studied petroleum jelly samples (Vaselines). Simon e t al. (2321)determined dienes in hydrocarbons by reaction chromatography with maleic anhydride. Schaefer et al. (2204 used a trapping technique for the analysis of C2-C5 hydrocarbons in rocks. Hartung et al. (1061)studied the analysis of C, fractions.
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Grob and Mathieu (1000 applied gas chromatography to the analysis of gaseous radiolysis products. Sojak et al. (2411) identified n-hexadienes in n-hexane catalytic hydrogenation products. Shcherbina e t al. (2251) used chromatographic polarity as a criteria for selecting aromatic extraction agents. Wainwright and Hoffman (2811) analyzed the oxidation products of u-xylene. Lobitz and Schmidt (1451) analyzed anthracene and its hydrogenation products. Hala et al. (1050 identified the products of cracking cumene on Ti-type zeolites by gas chromatography. Kuchhal et al. (1371) developed a rapid method for pseudocumene purity. Kuchhal (1381) also developed a method of analysis for aromatics boiling 5170 “C. Safonova et al. (1991)examined high boiling waxes. Rawat et al. (1931, 1941) used gas chromatography for the evaluation of some sulfur group solvents for the extraction of aromatics. Similarly, Murinov et al. (1621) studied sulfoxides and sulfones. Scheil and Harris (211Z) determined hydrogen-carbon ratios by post-column reaction. Uden et al. (2721) used pyrolysis techniques coupled with a gas chromatograph and computer for peak identification. Mihailescu et al. (1581) used azeotropes to separate pseudo-cumene from n-decane. Haensel (1021) used a crystalline metal alumino silicate to separate n-paraffins from hydrocarbon mixtures. Topuriya (2681) compared different methods for the determination of adamantane and l-methyl adamantane in petroleum. Garibaldi and Casalini (901) analyzed some crude gas oils by a variety of methods. Smolina et al. (2370 extracted urea deparaffination inhibitors from spent solutions with chloroform and benzene.
Metals in Oils R. E. Terrell Gulf Science and Technology Company, Pittsburgh, Pennsylvania
T h e past four years have seen a decline in the number of papers on metals in oils. The 1975 review listed 101 references, 1977 had 91, and this will cover ’75. Although this trend does make the reviewer’s task easier, it is disturbing to think that we are running out of significant approaches to the many problems with metals analyses in the petroleum field. Atomic Absorption Spectrometry. Grizzle et al., ( 1 6 d evaluated four techniques of sample preparation for the determination of nickel and vanadium in crude oils by atomic absorption. They found that direct flame analysis after dilution with an organic solvent gave erratic and inaccurate results as did direct, flameless analysis. Flame-analyzed, wet ashed methods and flameless analysis of diluted samples did yield reliable and reproducible data. Sebor and Lang (58J) confirmed the dependence of atomic absorption signals for nickel and vanadium in xylene solutions on the type of organometallic compound. The addition of halogens such as chlorine or iodine had no effect. Lang et al. ( 3 2 4 developed different calibration curves by diluting eight organometallic compounds of nickel of xylene. The differences were not reduced by a nitrous oxide -ethane flame but were less pronounced with a standard addition technique. Lange et al. (324 also found that the effect of addition of potassium or sodium on analysis for vanadium is dependent upon the particular vanadium, potassium, or sodium compounds involved and that the organic part ot the molecule or the type of metal-organic bond has more influence than potassium or sodium. They recommend against the addition of these compounds. Nickel a t the 0.1-ppm level was determined by Labrecque e t al., (3OJ) using a carbon-rod atomizer and samples dissolved in tetrahydrofuran stabilized with 0.1‘70 hydroquinone. After a background correction, the results agreed with those obtained by neutron activation. Marek et al. ( 3 8 4 determined nickel, vanadium, iron, sodium, magnesium, potassium, and calcium in petroleum in aqueous sulfuric acid. Interferences from any excess of these elements were studied. Russell and Campbell (55-4 were successful in developing a rapid, sensitive method for lead in gasoline. Applicable over the range 1-1000 mg lead per liter, the technique requires
dilution with methyl isobutyl ketone, shaking with a PhMe solution of iodine, and stabilization with methyltrioctyl ammonium chloride. Standards were prepared from lead chloride and extensive round-robin testing showed a reproducibility of 6 mg lead per liter and good agreement with results obtained by the IP270 method. Lead was detected in naphtha by Madec and LaVilla ( 3 6 4 by an extraction and complexing technique. The procedure is relatively long ( 3 h), but gave a precision better than 30% a t 10 ppb. LaVilla and Queraud ( 3 4 4 used 1% nitric acid to extract arsenic from naphtha treated with iodine in PhMe. The addition of magnesium nitrate permitted evaporation to a clear solution. LaVilla and Pean (334 measured mercury in natural gas by either wet or dry extraction followed by flameless atomic absorption. T h e method is simple enough for use a t the sample site. Acid digestion under reflux enabled Walker et al. ( 6 9 4 to determine trace selenium in petroleum. The selenium is measured above 10 ng g by hydrogen selenide generation followed by atomic a sorption with either n flame-heated vycor furnace or a hydrogen--argon---airflame. Experienced operators may achieve a precision of 8 to 30 ng g. A novel procedure for analysis of titanium in aircraft ubricating oils was offered by Saba and Eisentraut (66J). They diluted the sample with 4-methyl-2-pentene and shook for a few seconds with a mixture of hydrochloric and hydrofluoric acids. A total analysis time of 1-2 niin permitted a detection limit of 0.03 ppm. Difficult samples were placed in a pyrolytically coated graphite microboat and pyrolyzed in an air-ethane flame by Hwang et al. ( 1 9 4 prior to insertion into the cuvette of a flameless atomizer. The graphite atomizer was described and used to determine vanadium in crude oil, iron in pitch, and titanium in polypropylene. Kapoor et al. ( 2 3 4 showed that zinc enhances the absorhance of magnesium, lead, and silver; and that barium enhances magnesium and lead when analyzing for wear metals in used lubricating oils by atomic absorption. Improved water cooling to the electrode holders eliminated hot spots and permitted Alder e t al. ( 1 4 to determine elements in new or used iuhricating oils. Values for sensitivity, limits of detection, and rectilinear ranges were reported for calcium, magnesium, antimony. tin, and lead. Methods for the determination of metals in coal and petroleum were described by Pradhan ( * 5 ; M ) ~ Kaegler (215) gave detection limits of’ ilnrneless atomic absorption as compared to atomic absorption with flame. Sodium and vanadium in fuel oils, lead in gasoline, copper in feedstocks, and additive elements in lubricating oils were singled out. Since several factors complicate the direct determination from organic matrices by the flameless technique, aqueous solutions are often better. May and Presley i 4 N ) compared flameless atomic absorption with nelitron activation analysis for iron and nickel in crude oil residues. They found nickel results by atomic absorption high and iron low. Hofstader et al. (17 4 compared determinations of 13 elements by atomic absorpt,ion, neutron activation, and three other methods emphasizing detection of nanogram qualities. Neutron Activation Analysis (NAA). Mancini ( 3 7 4 reported a sensitivity of 0.35 ppm vanadium in fuel with no interference from sulfur, nickel, iron, or sodium when excited by a californium-252 source. Meier et al. C4UJ). using a small source (24 pg), found a limit of detection of about 1 ppm vanadium in oil with negligible interference from sodium and chlorine. On-stream analysis for vanadium was possihle with the californium-252 sources and cells described by Braun (7-A. Thermal-neutron activation was used by May and Presley ( 4 1 4 to “fingerprint” samples of beach asphalts h y determining the concentrations of antimony, bromine, chromium, cobalt, scandium, zinc, and the vanadium-to-nickel ratio. Buenafama and Lubkowitz ( 8 4 determined 17 trace elements by NAA to study heavy crude oils and asphaltenes. Over a 7-month period. the crudes lost homogeneity hut the asphaltenes remained stable and were used for st,andards. Computer-assisted data reduction of NAA spectra enabled Block and Dams (54to determine 22 elements in liquid fuels. Organometallic standards were used and standard deviations were calculated from counting statistics. Herkutova and Yakubson (45)used NAA to detect trace elements in petroleum from the Anastasier-Ttroitsk fold. In particular, they studied cobalt, gadolinium, arsenic, bromine, and copper. Zmijewska (745) reviewed problems with determinations as well as sample preparation methods for the radiochemical
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