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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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separation of mercury from environmental samples. Lower limits of detection were given for mercury in air, water, soil, rocks, flour, milk, sawdust, oil, and biological material. May and Presley ( 4 2 4 used y-ray activation to determine chromium and iron in crude oil. Sciuti (574 discussed portable instrumentation for neutron activation, neutron transmission, and X-ray fluorescence with an application of nondestructive analysis of paintings, silver coins, minerals, and oils. X-Ray Fluorescence Spectrometry. Energy dispersive X-ray fluorescence was used by Kubo and Bernthal (284to analyze NRS fuel oil for vanadium, iron, nickel, and molybdenum; and shale oil for iron, nickel, zinc, arsenic, and selenium. Spiked solutions were used for calibration. I t also enabled Yousif and AI-Shahristani ( 7 3 4 to determine sulfur and vanadium in crude oil. They claimed rapid simultaneous analyses with no significant effect of sulfur on the vanadium count rates. Rare earths in misch metal and steel were reported by Alota and Bartoli ( 2 J . T h e samples were oxidized, mixed with lithiiim borate -lithium carbonate flux, and cast in homogeneous buttons. A direct method was also described. Levinson and DePablo (354 reported elements heavier than iron, in particular thorium, niobium, tantalum, and tungsten, with lower limits of detection in the 2C-50 ppm range. Plesch (514 discussed the inherent errors in X-ray spectrometry and estimated them by simulation of standards. He also (525) used standard addition and standard-sample mixing procedures to suppress matrix effects. Barium and zinc were reported in crude oil. Krishnan ( 2 7 4 claimed analyses of samples in any matrix with standards in any convenient form by normalization involving corrections for scattering from the sample cell. Results were reported for zinc, iron, and lead in petroleum using solid or liquid standards. He recommended the addition of glycerol to avoid radiation damage to samples of tetraethyllead in gasoline. He also mentioned a technique for sulfur and chloride without a need for helium atmosphere. New methods for the analysis of lead, vanadium, sulfur, phosphorus, and chloride were reviewed by Kajikawa ( 2 2 4 . Emission Spectroscopy. Wear metals in jet lubricating oils were detected by Grampurohit and Rao ( 1 5 4 using dc arc emission spectrometry. The sample, mixed with gallium oxide, was charred and ashed. A lithium-graphite buffer provided smooth burning and recoveries of 75-122% were obtained for silver, aluminum, chromium, copper, iron, molybdenum, nickel, lead, tin, and titanium. Kapoor ( 2 4 4 reported results for cobalt and molybdenum in aluminumbased catalysts with the sample suspended in motor oil base stock and analyzed by rotating disk. Dutta and Guha (115) detailed a rapid, accurate means of estimating the vanadium content of fuel. They mixed the sample ash with copper oxide and graphite powder. Vanadium and nickel were studied by Katchenkov (25.4 to indicate the genetic relationship of petroleum-bearing rocks. Vanadium-nickel ratios were also compiled by Zul’fugarly and Babaev ( 7 5 4 as they analyzed for trace elements in Bahar Sea and Peschanyi deposits. Ohls ( 4 9 4 used rotrode spectroscopy in a carbon dioxide atmosphere and inductively coupled plasma to determine elements in oils. Detection limits were comparable to those obtained by pressed electrodes. One hundred references on the use of hollow-cathodedischarge tubes were reviewed by Krasil’shchik (264. Mosesco e t al. (455, 4 6 4 used atomic emission to determine sodium in gasoline, kerosene, and fuel oils. They described ashing and dilution techniques using sodium sulfonate for standardization. Electron Spin Resonance. Yamada et al. ( 7 1 4 investigated vanadium porphyrin chelates in Gach Saran residue and Nasirov et al. (47J) determined vanadium porphyrin complexes in various petroleums. Yamada and Sanada ( 7 0 4 followed the structure of vanadium compounds during heat treatment of a Gach Saran residuum and Athabasca tar sand bitumen. Quantitative results on quadrivalent vanadium were determined in distillation residues by Nikishenko et al. ( 4 8 4 . Results at the 0 . 5 5 - ~ glevel were in good agreement with those of atomic absorption or X-ray fluorescence. Miscellaneous. Vanadium in petroleum was determined by Sosnina and Rarsukova ( 6 3 4 using a colorimetric finish. Funk and Gomez ( 2 3 4 also used visible spectrometry to determine vanadium in toluene. Long-time centrifugation at
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high acceleration enabled Marek et al. (394to concentrate vanadium and nickel in crude oil. The distribution of vanadium and nickel porphyrins in rocks and petroleum was studied by Vinnikovskii et al. ( 6 8 4 using a photometric technique. Sebor et al. (594 separated vanadium and nickel porphyrins in crude oil by gel chromatography. Skostakovskii et al. ( 6 2 4 complexed the vanadium porphyrins with metal halides, regenerated in water, and extracted with chloroform. Serebrennikova et al. ( 6 0 4 used thin-layer chromatography and mass spectrography to identify two main types of vanadylporphyrins in petroleum. The mass spectra of metastable ions of synthetic and petroleum vanadylporphyrins were compared by Suboch et al. ( 6 4 4 . Anipenko et al. (34 described a method of solvent extraction, removal of pigmented impurities, and spectrometric analysis to study the nickel and vanadium porphyrin complexes in crudes. Yotsuyanagi et al., ( 7 2 4 extracted the ternary complex of nickel with 4-(2-pyridylazo)resorcinol and benzyldimethyltetradecyl ammonium chloride into chloroform. The addition of EDTA before extraction reduced metal ion interference. Interference from cobalt was masked by 3-methylglyoxime. High pressure liquid chromatography and atomic absorption were combined by Botre et al. ( 6 4 to determine the alkyllead compounds in gasoline. Shome et al. (614 used amperometric titration to detect lead in gasoline. They found that aluminum, zinc, arsenic, tin, fluoride, and cyanide do not interfere but iron, manganese, and copper need to be masked. Ratovskaya et al. ( 5 4 4 used a similar method for iron and vanadium in petroleum cokes. Fouad and .4min (124reported a new method for lead in gasoline and lube oils where the lead is extracted by nitric acid plus potassium chlorate and titrated with EDTA using xylenol orange indicator. The procedure is claimed to be fast and in good agreement with atomic absorption and ASTM D 526. A spectrophotometric technique enabled Hulanicki and Karwowska (184to determine iron, vanadium, copper, and lead in petrochemicals. The structural group composition of organosulfur compounds in petroleum were studied by Parfenova et al. (504 using mass spectrometry, paramagnetic resonance, and infrared spectroscopy. Sulfur compounds were also studied by Certkov et al. ( 9 4 by adsorption percolation with activated fine-spherical aluminosilicate. Techniques for isolation and characterization of sulfur compounds were developed by Jewel1 and Swansiger ( 2 0 4 . They obtained pure sulfur compounds and separated them by charge transfer and gradient elution chromatography. Goderdzishvili (24-Aformed sulfur photolysis products from the metal-containing sulfur compounds of petroleum products by irradiation with ultraviolet light. An improved Wickbold combustion technique was used by Kunkel (294to determine trace chlorine, arsenic, selenium, calcium, cadmium, lead, and zinc in various organic materials. Copper in gasoline was detected by Mori et al. ( 4 4 4 by chelation with o-hydroxyquinolphthalein and spectrophotometric measurement of absorbance a t 565 nm. Ugarkovic and Legin (664found that dry-transformation was more accurate and reproducible than wet oxidation and that burning time influenced accuracy in the determinations of sodium, potassium, and calcium in diesel and heavy fuel oil. Turina and Turina ( 6 5 4 detected lead from 0.002 and 0.1 ppm by thin-layer chromatography. Interference from sulfate ions was removed with barium chloride. A review of techniques for analysis of antimony, arsenic, beryllium. cadmium, chromium, cobalt. lead, manganese, mercury. molybdenum, nickel, vanadium, and selenium in trace amounts was presented by Davis et al. ( 1 0 4 .
Nonmetal Elements and Compounds W. E. Haines and D. R. Latham Lararnie Energy Technology Center, Lararnie Wyoming ~
Sulfur. Methods for the determination of total sulfur were the subject of many papers. The English (13K)and French (76K) versions of European Standard E N 41 (determination of the sulfur content of petroleum products by the Wickhold combustion method) have been published as BS 5379/EN 41 and N F T 60-142, respectively. Ehrenberger ( 4 1 K ) published
