Cherylyn W. Wright

Comparative chemical composition and biological activity of single- and two-stage coal liquefaction process streams

Abstract Samples from several integrated two-stage coal liquefaction (ITSL) process streams were collected under both normal and off-normal operating conditions. Selected crude materials were tested for their ability to initiate tumorigenicity in the initiation/promotion assay in mouse skin. Crude materials and their chemical class fractions were assayed for microbial mutagenic activity in the standard Ames test with S. typhimurium TA98, and selected samples were also subjected to the Chinese hamster ovary mammalian cell assay for mutagenicity. Mass spectral and gas chromatographic—mass spectral (g.c.—m.s.) analyses were carried out on these materials. Results were compared with those for analogous materials from solvent refined coal (SRC) single stage liquefaction processes. In general, the ITSL distillates were of higher molecular weight, higher hydroaromatic content, lower nitrogen content and were somewhat less alkylated than the analogous SRC materials. Compared to the SRC coal liquefaction materials, the ITSL distillates and bottoms materials collected under normal run conditions were substantially less active in both the microbial and mammalian cell mutagenicity assays. These same materials were also less active than ITSL samples collected under off-normal conditions. G.c.—m.s. analyses showed that ITSL materials collected under normal operating conditions were substantially reduced in amino polycyclic aromatic hydrocarbon content when compared to both the off-normal ITSL, and SRC materials. Activity of the ITSL materials as initiators of tumorigenesis was greater than expected, based on results from the in vitro assays and not significantly different than that of the SRC materials. The higher initial boiling point of the ITSL distillates probably accounts for much of their greater than expected initiating activity compared to the SRC materials.

Chromatographic chemical characterization of solvent refined coal I and II liquids for toxicological testing

SummaryHigh resolution gas chromatography and gas chromatography/mass spectrometry were employed to determine the components in samples of solvent refined coal (SRC) II naphtha, middle distillate, heavy distillate, and fuel oil blend and SRC-I light oil, wash solvent, and process solvent in concentrations higher than approximately 0.5%. Quantitation was based on the addition of n-alkane internal standards and peak area response of a flame ionization detector with the use of fused silica and glass capillary columns coated with SE-52 and SF-96. The major differences in the SRC-I and II materials were the molecular weight ranges and sizes of the chemical components found in the products, an effect of the differences in the nominal boiling ranges of the materials. Alkanes, alkenes, hydroxylated aromatics, hydrogenated and polycyclic aromatic hydrocarbon ring systems, and alkylated derivatives of the above were found in greatest concentration in the unfractionated materials. Sulfur and nitrogen heteroatomic species were in greates concentration in the higher nominal boiling range materials. A major purpose of these investigations was to develop a method to obtain data on the composition of these complex sample matrices for use in designing studies for toxicological evaluation of these materials.

Effect of process distillation on mutagenicity and cell-transformation activity of solvent-refined, coal-derived liquids

Abstract Blended SRC-II process streams, representing a full boiling range distillate material, were fractionally distilled into non-overlapping 50 °F cuts with boiling points between 300 and 850 °F. Another set of 18 distillate cuts were obtained with boiling points ranging between 138 and 1055 °F. Distillate cuts were assayed for mutagenic activity using the histidine reversion assay with Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, as well as for mammalian-cell transformation activity in the Syrian hamster embryo test, and DNA damage in the prophage induction assay. Samples were also separated into chemical class fractions by alumina column chromatography and analysed by high resolution gas chromatography so that the chemical composition of the cuts could be related to their relative activity in the different assays. In the mammalian cell transformation and microbial mutagenicity assays, significant activity was found almost exclusively in distillate cuts with components boiling > 700 °F, with the highest activity in the transformation assay observed for cuts > 800 °F. All of the distillate cuts showed increased levels of DNA damage as expressed by lambda prophage induction in Escherichia coli 8177. However, the greatest activity was associated with distillate cuts with boiling points in the 800 °F + range. Chemical analysis of the 50 °F distillate cuts showed a variety of polycyclic aromatic hydrocarbons (PAH) and amino-PAH compounds to be present in the distillate cuts boiling > 700 °F and essentially absent from cuts boiling

Effects of subchronic inhalation exposure of mice to a high-boiling coal liquid

Mice (CD-1) were exposed to aerosol concentrations of 0.0, 0.03, 0.14, or 0.69 mg/liter of heavy distillate (HD), a high-boiling coal liquid from the solvent-refined coal (SRC)-II process. Exposures were for 6 hr/day, 5 days/week for 13 weeks. Particle sizes ranged between 1.6 and 1.8 micron, mass median aerodynamic diameter, with a geometric standard deviation range of 1.9-2.5. Growth for high-dose males was significantly less than that of the control group. Compared to controls, weights of liver were significantly higher and those of ovaries and thymus significantly lower; these changes were significant on both absolute and relative weight bases. The number of red blood cells, volume of packed red cells, and hemoglobin concentration for animals from the high-dose group were significantly lower than those of controls. Microscopic examination of organ sections showed focal hepatic necrosis and nonspecific hepatopathy. Additionally, olfactory epithelial degeneration occurred in a dose-dependent manner. Results from this study indicated that exposure to HD caused adverse effects at the high dose and that these changes were either less severe or absent in middle-dose group mice. Comparison of these results with those for rats indicated that with rats the biological effects were more severe and present at lower doses than was observed for mice.

Fate of N-containing polycyclic aromatic compounds and microbial mutagenicity in SRC-II products on storage

Abstract Samples of a solvent refined coal II fuel oil blend were stored at 100 °C in air for 16 weeks, at room temperature, both diluted in methylene chloride and undiluted, for one year, and under nitrogen, diluted in methylene chloride, for three years. These conditions were chosen to increase the rates of the reactions producing chemical changes, and to mimic worst case storage conditions for samples subjected to microbial mutagenicity and other bioassay test systems. The samples kept at 100 °C were fractionated by neutral alumina column chromatography to obtain nitrogen-containing polycyclic aromatic compound fraction to determine the fate of nitrogen species on storage under these conditions. The test samples after storage were compared by high resolution gas chromatography to samples which had been stored at −20 °C under nitrogen for the same length of time. The amino-substituted polycyclic aromatic hydrocarbons and indole concentrations were found to have significantly decreased in the materials stored at 100 °C. There was a corresponding significant decrease in the mutagenicity of these samples as measured in a histidine reversion bioassay. The samples stored at room temperature and diluted at −20 °C also showed significant decreases in microbial mutagenicity believed to be caused by a decrease in amino-PAH concentration after storage. A sample of SRC-II heavy distillate was sub-sampled from varying levels of an undisturbed 60 dm 3 Teflon-lined stainless steel drum after storage for four years at 4 °C under nitrogen. A sludge had formed on the bottom of the container with the major chemical constituent being carbazole. Microbial mutagenicity analysis showed no significant mutagenicity differences in the samples taken from varying levels of the drum.

Detection of hazardous chemicals using field-portable Raman spectroscopy

A major challenge confronting emergency response, border control, and other security-related functions is the accurate, rapid, and safe identification of potentially hazardous chemicals outside a laboratory environment. Raman spectroscopy is a rapid, non-intrusive technique that can be used to confidently identify many classes of hazardous and potentially explosive compounds based on molecular vibration information. Advances in instrumentation now allow reliable field - portable measurements to be made. Before the Raman technique can be effectively applied and be accepted within the scientific community, realistic studies must be performed to develop methods, define limitations, and rigorously evaluate its effectiveness. Examples of a variety of chemicals (including neat and diluted chemical warfare [CW] agents, a CW agent precursor, a biological warfare (BW)-related compound, an illicit drug, and explosives) identified using Raman spectroscopy in various types of containers and on surfaces are given, as well as results from a blind field test of 29 unknown samples which included CW agent precursors and/or degradation products, solvents associated with CW agent production, pesticides, explosives, and BW toxins (mostly mycotoxins). Additionally, results of experimental studies to evaluate the analysis of flammable organic solvents, propellants, military explosives, mixtures containing military explosives, shock-sensitive explosives, and gun powders are described with safety guidelines. Spectral masks for screening unknown samples for explosives and nerve agents are given.

Comprehensive Review of Applicable Supercritical Fluid Extraction Research

This comprehensive supercritical fluid extraction (SFE) literature review is divided into three major sections. The first section describes the electronic literature search details including the abstract service used and the different topics searched. This section also contains an overview of the seven search topics that yielded relevant references along with a brief synopsis of the most significant literature citations. These seven groupings are (1) chemical warfare agents; (2) explosives; (3) hazardous chemicals; (4) poisons, toxins and mycotoxins; (5) toxic (lethal) chemical and toxicants; (6) pesticides in soil; and (7) pesticides from plant and animal tissues. The second section contains tables of each of these groupings. Each of the seven tables contains entries for individual literature citations listed along with the specific compounds or compound classes that are addressed. The third section refers to the abstracts used in the literature search.

Chemical basis for photomutagenicity in synthetic fuels and correlation with carcinogenicity

Photomutagens (chemicals that enhance the mutagenicity of non-ionizing radiation) have been detected in experimental coal- and oil shale-derived synthetic fuel samples using Salmonella typhimurium strain TA98 and fluorescent light. In this study, photomutagenic activity was measured among distillation and chemical class fractions from a blend of direct coal liquefaction process materials. Photomutagenicity increased with increasing boiling point and was concentrated in fractions enriched in neutral polycyclic aromatic compounds (neutral PACs). The photomutagenic activities of the materials tested correlate well with the previously reported tumorigenic activities of the same samples on mouse skin, but correlate poorly with the previously reported mutagenic activities of the same samples in the Salmonella/mammalian-microsome test (using strain TA98), in which neutral PAC-enriched fractions were not active. These data suggest that relatively high boiling neutral PACs are important chemical photomutagens in synthetic fuels and suggest the potential use of the photomutation assay as an improved, relatively simple, inexpensive and short-term bioassay for detecting carcinogens as mutagens in complex mixtures such as synthetic fuels.

Analysis of fuel using the Direct LSC method determination of bio-originated fuel in the presence of quenching

A modified version of the Direct LSC method to correct for quenching effect was investigated for the determination of bio-originated fuel content in fuel samples produced from multiple biological starting materials. The modified method was found to be accurate in determining the percent bio-originated fuel to within 5% of the actual value for samples with quenching effects ≤43%. Analysis of highly quenched samples was possible when diluted with the exception of one sample with a 100% quenching effect.

New method for evaluating irreversible adsorption and stationary phase bleed in gas chromatographic capillary columns

A novel method is described for the evaluation of irreversible adsorption and column bleed in gas chromatographic (GC) columns using a tandem GC approach. This work specifically determined the degree of irreversible adsorption behavior of specific sulfur and phosphorous containing test probe compounds at levels ranging from approximately 50 picograms (pg) to 1 nanogram (ng) on selected gas chromatographic columns. This method does not replace existing evaluation methods that characterize reversible adsorption but provides an additional tool. The test compounds were selected due to their ease of adsorption and their importance in the specific trace analytical detection methodology being developed. Replicate chromatographic columns with 5% phenylmethylpolysiloxane (PMS), polyethylene glycol (wax), trifluoropropylpolysiloxane (TFP), or 78% cyanopropylpolysiloxane stationary phases from a variety of vendors were evaluated. As expected, the results demonstrate that the different chromatographic phases exhibit differing degrees of irreversible adsorption behavior. The results also indicate that all manufacturers do not produce equally inert columns nor are columns from a given manufacturer identical. The wax-coated columns for the test probes used were more inert as a group than 5% PMS coated columns, and they were more reproducibly manufactured. Both TFP and 78% cyanopropylpolysiloxane columns displayed superior inertness to the test compounds compared to either 5% PMS- or wax-coated columns. Irreversible adsorption behavior was characterized for a limited range of stationary phase film thicknesses. In addition, the method was shown effective for characterizing column bleed and methods to remove bleed components. This method is useful in screening columns for demanding applications and to obtain diagnostic information related to improved preparation methods.