William M. Coleman

Characterization of organic fractions in solvent-refined coal by quantitative n.m.r. spectroscopy

Abstract A solvent-refined coal product obtained from Pittsburgh No. 8 coal has been preparatively separated into four sized fractions by gel permeation chromatography. Quantitative 1 H and 13 C Fourier-transform nuclear-magnetic-resonance results for the separated fractions are reported along with elemental and molecular weight analysis data. Observed trends for several average molecular parameters for these fractions (e.g. ( H C ) alp , ( H C ) aro , etc.) are discussed. The absence of certain organic functional groups, such as carbonyls, is also noted.

Inferences regarding the nature of solvent-refined coal (SRC)

Abstract Solvent-refined coal product has been subjected to numerous analytical techniques in an effort to ascertain its chemical nature. Electron spin resonance, 13C and 1H nuclear magnetic resonance, and mass spectroscopy along with elemental and molecular weight analyses have been employed. High-performance liquid chromatography via gel permeation separates tetrahydrofuran-soluble SRC into several size fractions. Nuclearmagnetic-resonance data strongly suggest that hexamethylphosphoramide-soluble SRC is approximately 95% aromatic in character.

Trace-element distribution in various solvent refined-coal fractions as a function of the feed coal

Abstract Solvent-refined coal (SRC), a tetrahydrofuran soluble and insoluble SRC derived from five different feed coals have been analysed for twelve metallic elements via flameless atomic absorption spectroscopy. Correlations of metal content in the SRC and pilot-plant processing conditions are discussed. A comparison of these data with previously reported metal analyses via energy-dispersive X-ray fluorescence analysis of similar SRC solid products is discussed. Three of the coals have been separated according to effective molecular size by gel-permeation chromatography and metal analyses have been performed on selected fractions. The possibility that some of the metals may be organically bonded is discussed.

Minor and trace metal analysis of a solvent-refined coal by flameless atomic absorption

Abstract Solvent-refined coal (SRC), THF ∗ -insoluble SRC, THF-soluble SRC and three of its ‘size-separated’ fractions have been analysed for eleven metallic elements via flameless atomic absorption spectroscopy. Prior to analysis each sample was wet ashed with equal quantities of concentrated H 2 SO 4 and 30% H 2 O 2 . Matrix effects were compensated for by the method of standard additions and deuterium-arc background correction. Mg, Al, K and Fe were found in greatest concentration in all samples. The concentration of Pb and Cd was measurable only in THF-insoluble SRC.

HPLC-MS Determination of Acrolein and Acetone Generated from 13C3 -Labeled Glycerol Added to Cigarette Tobacco Using Two Machine-Smoking Regimes

Abstract The extent of blend glycerol degradation in a burning cigarette to form acrolein and acetone has been quantitatively determined by the addition of glycerol-13C3 to three styles of a leading commercial cigarette brand. Multiple Cambridge pads soaked with a solution of 2,4-dinitrophenylhydrazine (DNPH) were employed to trap hydrazone derivatives of low molecular weight carbonyl compounds in both mainstream and sidestream smoke. High performance liquid chromatography coupled with negative ion mass spectrometry was used to isolate DNPH derivatives of the volatile carbonyl products of combustion and to ascertain their concentration. Acrolein, acetone, and propionaldehyde were the principal compounds of interest. The DNPH derivatives of acrolein-13C3 and acetone-13C3 were independently synthesized, and they served as external standards for absolute quantitation. The cost of fully labeled propionaldehyde precluded its use in this study. The brand styles selected for study represent the cigarette design features that are most prevalent in the U.S. market today and afford a representative range of standardized “tar” yields (14, 10, and 5 mg/cig, respectively by the Cambridge Filter Method). The brand styles studied are part of a commercial cigarette brand family that does not contain additives to the tobacco blend, including glycerol. Mainstream smoke was generated by an automated smoking machine employing the standard Cambridge Filter Smoking Regime and a more intense regime requiring larger, more frequent puffs and 100% vent blocking that is specified for regulatory purposes by the Canadian federal government. The research indicated that only a small fraction of added glycerol (~0.25%-0.30%, w/w) was converted to the two compounds of interest, with the larger portion generally observed in sidestream smoke. Less than 0.1% of the added glycerol was converted to acrolein in mainstream smoke for all cigarette designs and smoking regimes studied.

New Methodologies for Qualitative and Semi-Quantitative Determination of Carbon-Centered Free Radicals in Cigarette Smoke Using Liquid ChromatographyTandem Mass Spectrometry and Gas Chromatography-Mass Selective Detection

Abstract Several approaches were explored to develop a high throughput procedure for relative determination of 14 different carbon-centered free radicals, both acyl and alkylaminocarbonyl type, in cigarette smoke. Two trapping procedures using 3-cyano-2,2,5,5-tetramethyl-1-pyrrolidinyloxy, or 3-cyanoproxyl radical (3-CNP) were designed for this study: a) trapping in solution and b) trapping on a solid support which was a Cambridge filter pad. Fresh whole smoke and vapor phase smoke from mainstream cigarette smoke from Kentucky Reference Cigarettes 2R4F, as partitioned via an unadulterated Cambridge filter pad, were transferred into each trapping system in separate experiments. The 3-CNP coated Cambridge filter pad approach was shown to be superior to the impinger procedure as described in this study. Gas chromatography coupled with mass selective detection (GC-MS) was employed for the first time as an alternate means of detecting several relatively highly concentrated radical adducts. Liquid chromatography tandem mass spectrometry (LC-MS/MS) with precursor ion monitoring and selected ion monitoring (SIM) was used for detecting the large array of radicals, including several not previously reported: formyl, crotonyl, acrolein, aminocarbonyl, and anilinocarbonyl radicals. Relative quantitation was achieved using as external calibration standards of 4-(1-pyrrolidino)benzaldehyde and nicotine. It was determined that the yield of carbon-centered free radicals by reference cigarette 2R4F was approximately 265 nmoles/cigarette at 35 mL puff/60 sec interval/2 sec duration smoking conditions.

Synthesis, Purification, and Quantification of Fatty Acid Ethyl Esters After trans-Esterification of Large Batches of Tobacco Seed Oil

Summary The goal of the study was to quantify fatty acid ethyl esters (FAEE’s) produced from two large batches of tobacco seed oil after trans-esterification by heating in ethanol with sulfuric acid catalyst. Purification of the combined ethyl ester reaction products by removing as much of the color and odor from the final product as possible was achieved via conventional column chromatography with amorphous silica and tandem elution of first hexane and then ethyl alcohol as the mobile phase. Gas chromatography was used to quantify specific FAEE’s in the purified material. Recovery of pure FAEEs in batch #1 was near 87%; while, recovery of FAEE’s in batch #2 was greater than 89% with mass yields greater than 400 g of ethyl esters per esterification trial. The FAEE’s possessed no detectable aroma and only a slight yellow color after this chromatographic treatment. Supercritical fluid chromatography with a mobile phase of methanol/acetonitrile modified carbon dioxide and an octadecyl bonded silica stationary phase were used to characterize the purity of each batch of fatty acid ethyl ester product. No free fatty acids nor glycerolrelated impurities were detected in the purified transesterified product.This is the first report describing the optimized trans-esterification of tobacco seed oil on a relatively large scale coupled with subsequent purification and isolation of the resultant ethyl esters. [Beitr. Tabakforsch. Int. 26 (2015) 205-213] Zusammenfassung Ziel der Studie war die Quantifizierung der aus zwei großen Ansätzen Tabaksamenöl nach trans-Veresterung durch Erhitzen in Ethanol mit Schwefelsäure-Katalysator erhaltenen Fettsäureethylestern (FAEE). Die Reinigung der kombinierten Ethylester-Reaktionsprodukte durch Entfernen von so viel Farbe und Geruch vom Endprodukt wie möglich wurde mittels konventioneller Säulenchromatographie mit amorpher Kieselsäure und Tandem-Elution von zunächst Hexan und dann Ethylalkohol als mobile Phase erreicht. Es wurde Gaschromatographie verwendet, um spezifische FAEE im gereinigten Material zu quantifizieren. Die Wiederfindung von reinen FAEE in Ansatz 1 betrug knapp 87%; während die Wiederfindung von FAEE in Ansatz 2 größer als 89% war, mit Massenausbeuten von über 400 g Ethylestern pro Veresterungsversuch. Die FAEE besaßen nach dieser chromatographischen Behandlung keinen nachweisbaren Geruch und nur eine leicht gelbe Farbe. Es wurde Chromatographie mit überkritischen Fluiden mit einer mobilen Phase aus Methanol/ Acetonitril-modifiziertem Kohlendioxid und einer stationären Phase aus Octadecyl-gebundener Kieselsäure angewendet, um die Reinheit jedes Ansatzes des Fettsäureethylesterprodukts zu charakterisieren. Es wurden weder freie Fettsäuren noch glycerin-bedingte Verunreinigungen in dem gereinigten trans-veresterten Produkt nachgewiesen. Dies ist der erste Bericht, der die optimierte trans-Veresterung von Tabaksamenöl in relativ großem Maßstab zusammen mit anschließender Reinigung und Isolierung der entstandenen Ethylester beschreibt. [Beitr. Tabakforsch. Int. 26 (2015) 205-213] Resume Lobjectif de la présente étude était de quantifier les esters éthyliques dacides gras (FAEE) produits à partir de deux grands lots dhuile de graines de tabac soumis à une transéstérification éthanolique en présence dun catalyseur dacide sulfurique. La purification des produits combinés de la réaction des esters éthyliques visait la suppression, autant que faire se peut, de la couleur et de lodeur du produit final et fut accomplie via une chromatographie sur colonne conventionnelle avec silice sublimée et une élution en tandem de lhexane, dans un premier temps et de lalcool éthylique, dans un deuxième temps, en guise de phase mobile. La chromatographie en phase gazeuse fut utilisée afin de quantifier les esters éthyliques des acides gras spécifiques dans la matière purifiée. Le pourcentage desters éthyliques dacides gras purs récupérés dans le lot n°1 séleva à près de 87% tandis que le pourcentage desters éthyliques dacides gras purs récupérés dans le lot n°2 fut supérieur à 89% avec des rendements à la préparation supérieurs à 400 g desters éthyliques par essai destérification. Les esters éthyliques dacides gras ne possédaient pas darome détectable et ne présentaient quune légère coloration jaune à lissue de ce traitement chromatographique. Pour caractériser la pureté de chaque lot desters éthyliques dacides gras produits, une chromatographie en phase supercritique dont la phase mobile était un fluide composé de dioxyde de carbone modifié au méthanol/acétonitrile et une phase fixe composée dune silice greffée avec groupement fonctionnel octadécyle furent utilisées. Aucune impureté liée au glycérol ou à des acides gras libres ne fut détectée dans le produit transestérifié purifié. Notre article est le premier rapport décrivant la transestérification optimisée de lhuile de graines de tabac à une échelle relativement grande, ladite transestérification fut couplée à une purification et un isolement ultérieurs des esters éthyliques produits. [Beitr. Tabakforsch. Int. 26 (2015) 205-213]

Enhancement of volatile aglycone recovery facilitated by acid hydrolysis of glucosides from Nicotiana flower species.

Four different Nicotiana flowers (Nicotiana alata (alata), Nicotiana sylvestris (Sy), Nicotiana suaveolens (Su), and Nicotiana tabacum cv. Flue-Cured (FC)) from farms in Virginia and North Carolina were harvested and promptly quenched with liquid nitrogen and hand-ground prior to analysis. Each Nicotiana flower was pre-extracted with hexane to remove unbound volatiles. Fifteen standard compounds that were thought to be in the pre-extract were employed to aid in GC-MS identification and quantification. Glucosides were then chromatographically isolated and next hydrolyzed via 2 M sulfuric acid for 24 h at 75 °C. For each flower, the products of hydrolysis were extracted in tandem with hexane and dichloromethane (DCM) prior to analysis by GC-MS. The mixture of hexane and DCM extracts of the flowers after hydrolysis were then analyzed for each of 15 external standards via GC-MS to determine the concentration of any isolated flower-derived aglycone. Quantitative results for each of the possible 15 free volatile compounds extracted before and after hydrolysis were compared. Benzyl alcohol, phenethyl alcohol, and cis-3-hexenol were found in all Nicotiana both before and after acid hydrolysis. Enormous increases in the mass of benzyl alcohol and phenethyl alcohol were obtained with all flowers as a result of acid hydrolysis. With selected Nicotiana flowers, significant increases were observed for eugenol and cinnamaldehyde. The significant increases observed in cinnamaldehyde and eugenol upon mild acid hydrolysis strongly indicate that this approach could be a viable alternative process for the production scale isolation of these important natural flavor compounds.

Isolation, Fractionation, and Identification of Sucrose Esters from Various Oriental Tobaccos Employing Supercritical Fluids

Abstract Isolation, fractionation, and identification of sucrose esters from aged oriental tobacco employing supercritical fluids have been completed. Underivatized sucrose ester-rich extracts were obtained using supercritical CO2 at densities greater than 0.73 g/mL. Lower density CO2 provided extracts with notable amounts of tobacco derived material; yet, no detectable sucrose ester content. Preparative supercritical fluid chromatography (SFC) provided for an additional purification of the sucrose ester-enriched fraction after column optimization. Structural assignments of the SFC fractions were facilitated using gas chromatography/mass spectrometry (GC/MS) accompanied by N, O-bis(trimethylsilyl)trifluoroacetamide-dimethylformamide (BSTFA-DMF) derivatization of the free hydroxyl groups and high performance-liquid chromatography/mass spectrometry (HPLC/MS). From a relative quantitative perspective regardless of tobacco type, sucrose esters having an acetyl group on C6 of the glucose function (Group III) were in higher concentration compared to both the concentration observed for sucrose ester of Group I (acetyl group on C3 of fructose) and sucrose ester of Group II (no acetyl group on either glucose or fructose). Saturated fatty acid constituents were found to range from a maximum total of 18 carbons to a minimum total of 13 carbons. Unsaturated and isomeric fatty acid homologues were detected within the Group II sucrose ester.

Alkyl Pyrazine Synthesis via an Open Heated Bath with Variable Sugars, Ammonia, and Various Amino Acids

BACKGROUNDnSemi-quantitative characteristics of headspace volatile pyrazines which constituted around 1% by weight of the final product have been previously described. The influence of reactant concentration, reaction temperature, and reaction time on both the yield of total alkyl pyrazines and the distribution pattern of specific identified pyrazines has not been reported.nnnRESULTSnThe optimum synthetic conditions were 5 mol L-1 NH4 OH, 2 mol L-1 rhamnose, 0.5 mol L-1 leucine at 110°C for 2 h. The greatest total amount of pyrazines obtained was 17 280 µg of extracted product which translated into 31% 2,6-dimethyl pyrazine, 17% 2-methyl pyrazine, 15% 2-ethyl-6-methyl pyrazine, and 16% 2-isoamyl-6-methyl pyrazine.nnnCONCLUSIONnThe yield of synthesized pyrazines increased at higher temperatures. Quantitative total and specific pyrazine results as opposed to analysis of only headspace volatiles are more representative of pyrazine synthesis.