McClennen, WH

1996

Roving GC/MS: Mapping VOC Gradients and Trends in Space and Time

McClennen, W.H.; Vaughn, C.L.; Cole, P.A.; Sheya, S.A.N.; Wager, D.J.; Mott, T.J.; Dworzanski, J.P.; Meuzelaar, H.L.C. and Arnold, N.S.
Field Analytical Chemistry and Technology, 1(2):109-116, 1996. Funded by Hewlett Packard and ACERC.

Obtaining representative VOC (volatile organic compound) measurements in ambient environments that exhibit complex concentration gradients and/or trends is difficult when relying upon limited numbers of analyses obtained by simple pooling or averaging techniques. A more effective approach is to perform large numbers of analyses over a period of time to permit detailed mapping of profiling of local gradients and trends. Until recently, use of GC/MS (gas chromatography/mass spectrometry) techniques for rapid profiling or mapping operations was not feasible because of sample speed limitations. This article describes a roving GC/MS system based on the combination of a Hewlett-Packard model 5972 MSD (mass selective detector), a FemtoScan Enviroprobe repetitive vapor sampling inlet with short capillary GC column, and Alcatel Micro HV oil-less vacuum pump stack and a Pentium notebook PC running under Windows 95. The roving system is further equipped with differential GPS (global positioning system) and radio transceiver capabilities thereby permitting remote tracking of vehicle location and local VOC concentrations. Laboratory tests demonstrate lower detection limits of approx 4 ppb for BTX (benzene, toluene, and zylene), corresponding to minimum detectable quantities of a mixture of volatile ketones. Demonstrated outdoor performance, using a zero-emission electric vehicle, includes measurement of low ppb BTX levels along a 6 km urban route at 15 s (~ 150 m) intervals while moving at an estimated average speed of 35 km/hr. Indoor measurements of toluene concentrations in the low to mid ppm range at 6 s (~5 cm) intervals along a 6 m long path reveal a high degree of spatial and temporal variability in VOC concentrations. Mobility, specificity, sensitivity and speed of the roving GC/MS method make this a promising candidate method for rapid outdoor and indoor screening, monitoring and mapping of VOCs.

Field Evaluation of a Prototype Man-Portable GC/MS

Arnold, N.S.; Du, W.H.; Sheya, S.A.N.; Mihamou, H.; Dworzanski, J.P.; Hall, D.L.; McClennen, W.H. and Meuzelaar, H.L.C.
Proceedings of the Ninth International Symposium On Field Screening Methods for Hazardous Wastes and Toxic Chemicals, 2:903-910, 1996. Funded by ACERC, US Army Electrical Research Development and Engineering Center.

In recent years, a man-portable gas chromatography/mass spectrometry (GC/MS) system has been developed based on a Hewlett-Packard 5971 MSD and a unique automated vapor sampling (AVS) transfer-line (TL) GC system for direct sampling of ambient chemical vapors [1,2]. The vacuum system and power supplies were replaced to facilitate operation on 24 V DC batteries for up to 4 hours after startup on a transportable docking station. The gas chromatography was performed on a short (2 m) capillary column under isothermal conditions in a small oven to minimize power usage. Repetitive samples were taken at 10 to 60 s intervals using an automated vapor-sampling inlet.

In initial testing, the prototype system has been used for monitoring of gasoline vapors. Ambient levels of 6.0 ppm benzene, 4.1 ppm toluene, 0.22 ppm ethylbenzene, 1.1 ppm m-and p-xylene and 0.25 ppm 0-xylene were measured near a busy gas station. The gradient mapping or source tracking capabilities of the backpack-mounted system have also been demonstrated in tests with a simulated gasoline leak.

This paper will describe recent work to further evaluate the capabilities and limitations of the prototype system. Results will be described in terms of the practical utility of portable GC.NS for identification and quantification of unknown vapors.

Design Considerations for a Novel Miniaturized Tandem GC Method for Field Screening Applications

Sheya, S.A.N.; Dworzanski, J.P.; McClennen, W.H.; Meuzelaar, H.L.C. and Arnold, N.S.
Proceedings of the Ninth International Symposium On Field Screening Methods for Hazardous Wastes and Toxic Chemicals, 1:213-220, 1996. Funded by ACERC.

Development of a potentially field-portable tandem GC (GC/GC) method involving a novel, dynamic coupling between two short capillary GC columns-each of which is independently optimizable with regard to temperature and flow-is described. The relatively slow (5-25 sec wide), GC peaks eluting from the first (1.2 m x 530 µm) column are sampled repetitively at 1-5 sec. Intervals into the second (0.8 m x 100 µm) column. Dynamic coupling by means of fluidic AVS (Automated Vapor Sampling) technology, rater than through trap-and-desorb interfaces, reduces power requirements. Further power reduction is achieved by isothermal operation of both columns. If properly designed and optimized the sensitivity of dynamic GC/GC techniques should approach that of one-dimensional GC, depending on the type of detector used. Since a universally responsive, subambient pressure, low weight and low power detector for field-portable GC/GC has not yet been found, a Hewlett Packard MSC (Mass Selective Detector) was used throughout the present study. At a maximum scan rate of 35 spectra (over 5 amu mass range), the minimum practical GC peak width eluting from the second column is limited to approximately 100 msec. The feasibility of producing comprehensive, two-dimensional chromatograms of multicomponent mixtures, volatile compounds, including C3-C6 ketones, is demonstrated.

1994

Field Portable Hyphenated Instrumentation: The Birth of the Tri-Corder?

McClennen, W.H.; Arnold, N.S. and Meuzelaar, H.L.C.
Trends in Analytical Chemistry, 13(7):286-293, 1994. Funded by Hewlett Packard and US Army.

The "tricorder," the tiny universal sensor of "Star Trek" science fiction fame, might be the ultimate objective for developers of field-portable instrumentation. The advantages of multi-dimensional ("hyphenated") analytical methods over one-dimensional techniques in working toward such a goal are based upon the degree of correlation of the information from the combined analytical techniques. With appropriately selected techniques that yield complementary (orthogonal) information, the actual resolution of the hyphenated technique is the product of the resolution of the two techniques. In effect, the whole of a suitable hyphenated system is greater than the sum of its parts.

The most widely used hyphenated method, combined gas chromatography-mass spectrometry (GC-MS), is regarded as the definitive method for certain applications and has become the officially required procedure for numerous environmental, clinical and occupational health or safety related tests. In fact, in most laboratories GC-MS has all but replaced the use of one-dimensional GC and MS techniques. Consequently, results based on characterization of complex environmental samples by GC or MS alone would tend to be disregarded or seen as tentative, at best. Yet, the use of one-dimensional GC and MS techniques represents the present state-of-the-art in field screening methods. The demonstration of hyphenated analytical techniques in field application via the use of mobile laboratories has been established in the last 10 years by a number of researchers using MS-MS or GC-MS techniques. However, it is appropriate to consider whether a field laboratory constitutes a truly field-portable analytical technique.

In-situ applications are an area of field portability where the use of hyphenated methods is a recent phenomenon that can be expected to continue due to the considerable power of these approaches. However, the large-scale acceptance of these techniques in the field will depend upon overcoming the constraints of inherent higher cost, complexity, size, weight and power requirements.

On the other hand, hyphenated techniques should certainly not be seen as a panacea for every analytical problem, whether in the laboratory or in the field. Although the information provided by a multi-dimensional method is often much greater than the summed information obtainable from the component techniques, a poorly designed hyphenated experiment may end up amplifying the characteristic weaknesses and shortcomings of the component methods and provide little or no useful information. In effect, the use of sophisticated hyphenated methods is certainly not a satisfactory way to compensate for a poor analytical technique!

1993

Development of a Laser Devolatilization Gas Chromatography/Mass Spectrometry Technique for Single Coal Particles

Maswadeh, W.; Arnold, N.S.; McClennen, W.H.; Tripathi, A.; DuBow, J. and Meuzelaar, H.L.C.
Energy & Fuels, 7 (6):1006-1012, 1993. Funded by ACERC.

A CO2 laser Py-GC/MS system capable of identifying substantial numbers of pyrolysis products from single coal particles in the 50-15-µm range is reported. Also, a specially designed two-wavelength radiation thermometer module with integral video microscope produces reliable temperature/time profiles of single coal particles during rapid laser heating. A novel microbeam footprint technique using thin quartz wafers in combination with videomicroscopy greatly facilitates laser beam focusing and alignment operations. Comparison of an EDB type particle levitator with an EM grid type particle support system reveals considerable advantages of the EM grid approach with regard to tar collection efficiency, particle position stability, particle visualization, and recoverability of residual char particles. However, possible cooling effects of the grid on highly thermoplastic particles require further study. The feasibility of simulating PCC conditions with regard to heating rates and final particle temperatures is demonstrated with complete devolatilization of 100 µm diameter particle being observed within 10 ms. The nature and relative abundance of major pyrolysis products observed at typical laser heating rates (>=105 K/s) are found to be closely similar to those observed with Curie-point pyrolysis techniques at heating rates in the 10²-10³ K/s range. Spherocarb particles of approximately 102-µm diameter, e.g., impregnated with suitable coal tar compounds are shown to provide useful model samples for system optimization and calibration purposes.

Microscale Simulation of High Pressure Thermal and Catalytic Conversion Processes in Coal and Waste Polymers with On-Line GC/MS

Liu, K.; Jakab, E.; McClennen, W.H. and Meuzelaar, H.L.C.
Proceedings of the 206th American Chemical Society National Meeting, ACS Preprints, Fuel Chem. Div., 38 (3): 823-830, Chicago, IL, August 1993. Funded by US Department of Energy.

Over 279 million automotive tires are discarded in the United States each year. These used tires cause serious environmental problems since they are non-biodegradable, occupy considerable landfill space, and emit noxious fumes when burned. One of the promising approaches to deal with used rubber is the co-processing of it with coal to produce hydrocarbon liquids for use as fuels and specialty chemicals. Recently there have been numerous studies on co-processing of tire rubber and coal since depolymerized rubber has good solvent properties and the carbon black which constitutes of about 20-30% of the rubber is a good catalyst for depolymerization and possibly enhanced coal liquefaction. Monitoring sample weight loss as a function of temperature with on-line analysis of the evolved products during the co-processing reactions is necessary to elucidate mechanisms and kinetics of the key conversion reactions. Due to the high pressure and high temperature required by some of the most interesting processes, it is difficult to continuously monitor the weight loss and reaction intermediates without interrupting the reactions.

On-line analysis techniques for high-pressure conversion reactions have been reported previously, but these systems did not monitor total weight loss vs reaction temperature. They also were not applied directly to coal conversion studies because of the strong potential for plugging of sample orifices with pulverized coal. Microscale simulation of coal conversion reactions has been performed by high-pressure thermogravimetry with on-line combined gas chromatography and mass spectrometry (TG/GC/MS). It requires only a small sample size and can be operated at high temperature and pressure. The weight loss and low molecular weight products can be monitored vs reaction temperature. Analysis of pyrolysis and hydropyrolysis of coal, rubber and coal with tire rubber, with our without catalyst, by high pressure TG/GC/MS are reported here.

Development of On-Line GC/MS Monitoring Techniques for High-Pressure Fuel Conversion Processes

Nie, X.; McClennen, W.H.; Liu, K. and Meuzelaar, H.L.C.
Proceedings of the 206th American Chemical Society National Meeting, ACS Preprints, Fuel Chem. Div., 38 (4), Chicago, IL, August 1993. Funded by US Department of Energy.

It is well known that on-line analytical methods offer considerable advantages over conventional off-line procedures for fuel conversion processes. Although many on-line spectroscopic detection systems for thermal process reactors have been reported, they have had only very little application to high-pressure reactors. Therefore, relatively little is known about the precise pathways and intermediate products involved in high-pressure reactions. The application of real time, on-line chromatographic and/or spectroscopic techniques capable of throwing light on these processes is hampered by the high temperatures and pressures inside the reactor which complicate direct interfacing to standard analytical instruments.

Thermogravimetry (TG) can provide detailed information on thermally driven conversion reactions, especially when combined with on-line detection and identification techniques such as Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS). However, high pressure TG systems have only recently become available for studying the basic pyrolysis and especially hydropyrolysis reactions involved in coal liquefaction, thus, the combined chromatographic/spectroscopic interfaces for such high pressure systems are only now producing results. Other high-pressure reactors of interest include those used to study the thermal processes in liquid fuels or in solvent-based coal conversion. Thus there have been recent reports of on-line GC/MS monitoring of a high pressure recirculating autoclave used to study coal derived liquid model compounds. Other work in our laboratory has examined the supercritical pyrolytic degradation of jet fuels with on-line GC/IR/MS. Several of these systems have involved the use of a patented automated vapor sampling (AVS) inlet with short column or so-called "transfer line" gas chromatography (TLGC) with MS or FTIR.

This paper presents the experimental descriptions and results from three high-pressure systems using a variety of components. The first is a high pressure TG/GC/MS system used to study coal hydropyrolysis. The other two use quartz-tubing reactors to examine the liquid and gaseous products from the thermal decomposition of jet fuels.

Investigation of Incineration Characteistics of Waste Water Treatment Plant Sludge

McClennen, W.H.; Lighty, J.S.; Summit, G.D.; Gallagher, B. and Hillary, J.M.
Combustion Science & Technology, 1993 (in press). (Presented at the Third International Congress on Toxic Combustion Byproducts, Cambridge, MA, June 1993.) Funded by Kodak, Presidential Young Investigators and ACERC.

Incineration is an important disposal method for the large volumes of sludge produced by industrial and municipal wastewater treatment. This paper describes analytical methods developed for examining industrial sludge incineration processes and the dependence of potential products of incomplete combustion (PICs) on the sludge composition. A surrogate sludge was developed from peat, calcium and iron salts, and a waste water-treatment polymer suspension to simulate incineration characteristics of the real sludge while allowing for controlled variation of its composition. Experiments were conduced under both oxidative and pyrolysis conditions, in reactor systems ranging from microscale up to bench scale with on-line analytical instrumentation. The organic products emitted from the surrogate were quite similar to those of the sludge, with the exception of products from certain synthetic polymers. Significant quantities of aromatic hydrocarbons were emitted from the combustion of cellulosic and lignin fractions of the material even without the presence of those specific compounds in the original waste. The presence of the metal salts and the additional water they retained significantly affected the peak hydrocarbon concentration by delaying the onset of emissions and lengthening their duration. The amount of polystyrene and polymethylmethacrylate in the real sludge made their decomposition products important potential PICs, which would need further combustion.

On-Line Monitoring of Formaldehyde in Combustion Gases Using Gas Chromatography/Mass Spectrometry

McClennen, W.H.; Sheya, S.A.N.; Arnold, N.S.; Meuzelaar, H.L.C.; Larsen, F.S. and Silcox, G.D.
Incineration of Hazardous Wastes-2; Toxic Combustion By-Products:545-555, (in press). Funded by Consortium for Fossil Fuel Liquefaction and ACERC.

This paper describes a method for on-line gas chromatography/mass spectrometry (GC/MS) of formaldehyde in combustion gases. The method uses a recently developed vapor-sampling inlet to monitor the concentration of formaldehyde and other products of incomplete combustion (PICs) from the burning of plain and phenol-formaldehyde resin treated wood chips. Other PICs that were simultaneously monitored included ketene, propylene, propyne and acetaldehyde. The direct analysis method has detection limits of less than 1 ppm for the reactive formaldehyde and excellent selectivity for determinations in the complex mixtures of combustion products. The rapid sampling technique allows monitoring of transient events of only a few minutes or less duration. Examples of the technique include the detection of sample line problems and the comparison of PIC concentrations from different points in the combustion exhaust stream.

Novel Automated Chromatographic and Spectroscopic Techniques for On-Line Combustion By-Product Monitoring

Meuzelaar, H.L.C.; McClennen, W.H.; Arnold, N.S.; Dworzanski, J.P. and Kim, M.-G.
Incineration of Hazardous Wastes-2; Toxic Combustion By Products: 513-530, (in press). Funded by Consortium for Fossil Fuel Liquefaction and ACERC.

A new generation of on-line combustion product and by-product monitoring techniques based on the combination of a novel, automated vapor sampling (AVS) concept with so-called "transfer line gas chromatography" (TLGC) and any of several possible spectroscopic techniques is described. The automated vapor sampling method is characterized by the exclusive presence of quartz glass surfaces in the path of sample molecules between sampling point and detector, as well as by very short vapor sampling times (typically ˜ 1 sec), thereby facilitating rapid chromatographic separation using a short length (e.g., 1-6 ft) of fused silica capillary GC column. Laboratory test data are provided for three different instrumental configurations, namely AVS-TLGC in combination with: (1) mass spectrometry (MS); (2) MS and Fourier transform infrared spectroscopy (FTIR); and (3) ion mobility spectrometry (IMS).

Whereas on-line GC/MS monitoring is clearly the preferred approach when maximum specificity and sensitivity are required, GC/IR has important advantages for monitoring gaseous combustion products and distinguishing isomeric species and on-line GC/IMS appears to offer a sensitive, relatively inexpensive and simple monitoring tool for selected target compounds.

Thermogravimetry/Gas Chromatography/Mass Spectrometry and Thermogravimetry/Gas Chromatography/Fourier Transform Infrared Spectroscopy: Novel Hyphenated Methods in Thermal Analysis

McClennen, W.H.; Buchanan, R.M.; Arnold, N.S.; Dworzanski J.P. and Meuzelaar, H.L.C.
Analytical Chemistry, 65:2819-1823, 1993. Funded by Hewlett Packard and ACERC.

Two doubly hyphenated, thermogravimetry-based analytical techniques, viz. TG/GC/MS and TG/GC/IR, are described. A valveless, quartz, heated sample path between TG furnace and GC column minimizes losses of products. Furthermore, combination of a pulsed automated vapor-sampling inlet and a transfer line type GC column permits high-speed GC identification of individual TG products while maintaining sufficiently high temporal resolution with the ~1-min sampling interval to provide kinetic information about the underlying reaction mechanisms. Example analyses on poly (alpha-methylstyrene), a styrene-isoprene block copolymer, and wood demonstrate the techniques' capability for monitoring specific minor products and isomers.

Interfacting High-Speen Transfer Line Gas Chromatography to Ion Trap Mass Spectrometry; Advantages and Limitations

Arnold, N.S.; McClennen, W.H. and Meuzelaar, H.L.C.
Proceedings of the 41st ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, CA, June 1993. Funded by US Army/Electrical Research Development and Engineering Center and ACERC.

The Ion Trap Detector (ITD, Finnigan-MAT) was originally introduced as a gas chromatography (GC) detector for laboratory bench top GC/MS analyses. Its introduction coincided with a rising interest in a vacuum outlet short column GC/MS for high-speed chromatographic separations. Advantages for such short column applications, including high operating pressures (10-3 torr) sensitivities (.1 fg/s) and scan speeds (5500 amu/s) relative to conventional quadruple instruments, have fueled interest in ion trap based instruments for high speed, high resolution GC/MS analyses. Subsequent interest has been fueled by new developments in mobile instruments, high sensitivity MSn capability, AGC-based dynamic range enhancement, and axial modulation based resolution enhancement.

The Next Step in Miniaturization Toward Personal GC/IMS

Arnold, N.S.; Dworzanski, J.P.; Meuzelaar, H.L.C. and McClennen, W.H.
Proceedings of US Army Electrical Research Development and Engineering Center Science Conference on Chemical Defense Research, Aberdeen, MD, November 1993. Funded by US Air Force.

Field portable gas chromotography/ion mobility spectrometry (GC/IMS) techniques have been identified as an important area of development for CW detection. Recent developments of smaller, personal IMS detection devices offer new prospects for miniaturization of a combined personal GC/IMS unit that would have considerable size and cost advantages over its larger predecessors. The following is a preliminary examination of feasibility of personal GC/IMS based on an automated vapor sampling-transfer line gas chromatography (AVS-TLGC) approach previously used in developing hand portable GC/IMS instrumentation. Special focus is placed upon developing low power GC interfacing strategies for an existing prototype miniature IMS device. Parameters such as GC column position and flow as well as IMS purge flows are examined for their effects on sensitivity and resolution.

1992

Optimization of Transfer Line Gas Chromatography for Direct Atmospheric Vapor Sampling Ion Mobility Spectrometry Application

Arnold, N.S.; Kim, M.-G.; McClennen, W.H. and Dworzanski, J.P.
Workshop on Ion Mobility Spectrometry, Mescalaro, AZ, June 1992. Funded by US Army/Chemical Research Development and Engineering Center.

An automated vapor sampling (AVS) device has proved powerful for atmospheric (and other) vapor sampling applications when coupled with the "preseparation" available via rapid transfer line gas chromatography (TLGC) prior to detection by a "smart" detector. Initial applications of AVS TLGC utilized mass spectrometric (MS) detection along with rapid repetitive sampling to monitor on-line test reactors and industrial processes. Subsequent work extended this technique to AVS TLGC/FTIR for the monitoring of evolution products from a thermogravimetric analyzer. Most recently this technique has been extended to ion mobility spectrometry (IMS).

Because the AVS device samples directly from the ambient environment at the inlet into the GC column without any intervening mechanical parts (e.g. syringes, pumps, etc.), the GC column itself must function as a pressure restrictor between the sampled environment and a detector operated at reduced pressure. This technique found its first application in AVS TLGC/MS where the merits of vacuum outlet GC and the requirement of capillary flow restriction are obvious. Yet, the extension to detectors that are ordinarily operated at atmospheric pressure (i.e., IMS and FTIR) by pulling up to ½ atmosphere of vacuum on the detector cell has also proved successful.

These successes have motivated a search for "optimal" performance based upon the selection of appropriate column parameters for both separation and flow restriction criteria. Specifically, this paper evaluated the performance for AVS TLGC/IMS separations from the perspective of resolution, speed of separation and sensitivity.

Hydrocarbon and Formaldehyde Emissions from the Combustion of Pulverized Wood Waste

Larsen, F.S.; McClennen, W.H.; Deng, X.-X.; Silcox, G.D.and Allison, K.
Combustion Science and Technology, 1992 (in press). (Also presented at The Second International Congress on Toxic By-Products: Formation and Control, Salt Lake City, UT, March 1992). Funded by Weyerhaeuser Corp. and ACERC.

Hydrocarbon and formaldehyde emissions from the combustion of pulverized wood waste were measured in 100 kW, cylindrical combustion chamber measuring 0.61 by 0.61 m. The wood was pneumatically conveyed to the burner and natural gas was used as an auxiliary fuel. The wood was screened prior to feeding so that its size distribution was representative of the suspension phase of a stoker boiler. Chamber wall and gas temperatures ranged from 920 to 1200 K and oxygen concentrations ranged from 2 to 9 percent, dry. Two types of waste were studied, plain wood and wood that was impregnated with a phenol-formaldehyde resin. The latter was a by-product of particleboard production. In general, the emissions of products of incomplete combustion (PICs) from the resinated waste were higher than those produced by plain wood. This may have been due to three factors: 1) the resinated wood was slightly wetter than the plain wood (6-9 percent by weight vs. 3 percent), 2) there was a difference in particle size distribution between the two materials as received, the resinated wood being larger, and 3) the resin may have had an effect on the emissions. Ultimate analyses of the two wastes showed no significant differences, other than moisture, in composition. At temperatures above 1200 K, total hydrocarbon emissions were roughly 10 to 29 ppm and formaldehyde emissions were less than the detection limit of 1 ppm. Typical waste wood boiler temperatures are roughly 1600 K. Hence, unless there are cool, poorly mixed regions in the full-scale facility, hydrocarbon and formaldehyde emissions should not be significant. However, the emissions from burning the two different types of wood would probably be different if all operating parameters in the wood-fired boiler are held constant.

1991

The Chemical Structure and Petrology of Resinite from the Hiawatha "B" Coal Seam

Crelling, J.C.; Pugmire, R.J.; Meuzelaar, H.L.C.; McClennen, W.H.; Huai, H. and Karas, J.
Energy & Fuels, 5:688-694, 1991. Funded by US Department of Energy and ACERC.

The objective of the present study is to examine the chemical structure and composition of Utah Wasatch Plateau coal resinite. Macerals were separated from the coal matrix by hand picking, sink-float treatments, and/or density gradient centrifugation (DGC). DGC separation was found to produce highly purified resinite fractions. Resinite-rich Wattis Seam coal samples were collected from fresh mine faces and, after varying degrees of concentration, subjected to C-13 magic angle spinning NMR, Curie-point pyrolysis MS, and Curie-point pyrolysis GC/MS in addition to petrographic analysis and fluorescence microscopy as well as conventional (e.g., ultimate analysis) characterization methods. The data obtained confirm recent findings indicating that the abundant blue/green fluorescing resinite component is a polymeric substance composed of sesquiterpenoid repeat units with a median size of 204 Da, corresponding to the empirical formula C15H24. The monomeric sesquiterpenoid units obtained during pyrolysis appear to represent different degrees of unsaturatization ranging from C15H26 sesquiterpenes to the aromatic C15H18 cadalene. Clearly, sesquiterpenoids constitute the bulk of extractable resinite in Wasatch Plateau field coal and are likely to be important precursors of the abundant extractable alkynaphthalene moieties in such coal.

Hydrocarbon and Formaldehyde Emissions from the Combustion of Pulverized Wood Waste

Larsen, F.S.; McClennen, W.H.; Deng, X.-X.; Silcox, G.D. and Allison, K.
Combustion Science and Technology, 1991 (in press). Funded by Weyerhaeuser Corp. and ACERC.

Hydrocarbon and formaldehyde emissions from the combustion of pulverized wood waste were measured in 100 kW, cylindrical combustion chamber measuring 0.61 by 0.61 m. The wood was pneumatically conveyed to the burner and natural gas was used as an auxiliary fuel. The wood was screened prior to feeding so that its size distribution was representative of the suspension phase of a stoker boiler. Chamber wall and gas temperatures ranged from 920 to 1200 K and oxygen concentrations ranged from 2 to 9 percent, dry. Two types of waste were studied, plain wood and wood that was impregnated with a phenol-formaldehyde resin. The latter was a by-product of particleboard production. In general, the emissions of products of incomplete combustion (PICs) from the resinated waste were higher than those produced by plain wood. This may have been due to three factors: 1) the resinated wood was slightly wetter than the plain wood (6-9 percent by weight vs. 3 percent), 2) there was a difference in particle size distribution between the two materials as received, the resinated wood being larger, and 3) the resin may have had an effect on the emissions. Ultimate analyses of the two wastes showed no significant differences, other than moisture, in composition. At temperatures above 1200 K, total hydrocarbon emissions were roughly 10 to 29 ppm and formaldehyde emissions were less than the detection limit of 1 ppm. Typical waste wood boiler temperatures are roughly 1600 K. Hence, unless there are cool, poorly mixed regions in the full-scale facility, hydrocarbon and formaldehyde emissions should not be significant. However, the emissions from burning the two different types of wood would probably be different if all operating parameters in the wood-fired boiler are held constant.

On-Line Monitoring of Formaldehyde in Comubustion Gases Using Gas Chromatography/Mass Spectrometry

McClennen, W.H.; Sheya, S.A.N.; Arnold, N.S.; Meuzelaar, H.L.C.; Deng, X.-X.; Larsen, F.S. and Silcox, G.D.
Combustion Science and Technology, 1991 (in press). Funded by ACERC.

This paper describes a method for on-line gas chromatography/mass spectrometry (GC/MS) of formaldehyde in combustion gases. The method uses a recently developed vapor-sampling inlet to monitor the concentration of formaldehyde and other products of incomplete combustion (PICs) from the burning of plain and phenol-formaldehyde resin treated wood chips. Other PICs that were simultaneously monitored included ketene, propylene, propyne and acetaldehyde. The direct analysis method has detection limits of less than 1 ppm for the reactive formaldehyde and excellent selectivity for determinations in the complex mixtures of combustion products. The rapid sampling technique allows monitoring of transient events of only a few minutes or less duration. Examples of the technique include the detection of sample line problems and the comparison of PIC concentrations from different points in the combustion exhaust stream.

Vapor Sampling Device for Direct Short Column Gas Chromatography/Mass Spectrometry Analyses of Atmospheric Vapors

Arnold, N.S.; McClennen, W.H. and Meuzelaar, H.L.C.
Analytical Chemistry, 63:299-304, 1991. Funded by ACERC.

A number of methods are currently used for atmospheric vapor and gas sampling with mass spectrometric detection and identification. Direct mass spectrometry (MS) sample introduction methods include fixed molecular tasks, atmospheric pressure ionization, trap and desorb, and membrane separation, while gas chromatography/mass spectrometry (GC/MS) methods employ trap and desorb, direct bubbler solvent injection, sample loops, and pressurized gas plug introduction. Approaches vary depending upon whether MS, tandem MS, or GC/MS analyses are desired. Direct MS and tandem MS analyses typically give quick response times and high repetition rates but are often sensitive to interferents, including atmospheric constituents, while GC/MS analyses offer greater specificity but with typically lower results.

The Application of a Mobile Ion Trap Mass Spectrometer System to Environmental Screening and Monitoring

McClennen, W.H.; Arnold, N.S.; Meuzelaar, H.L.C.; Ludwig, E. and Lighty, J.S.
2nd International Symposium on Field Screening Methods for Hazardous Wastes and Toxic Chemicals, Las Vegas, NV, February 1991. Funded by ACERC, Environmental Protection Agency, Finnigan MAT Corp., US Army Chemical Research Development and Engineering Center and Utah Power and Light.

This paper presents examples of the use of a mobile Ion Trap Mass Spectrometer (ITMS, Finnigan MAT) for on-site environmental screening and monitoring of vapors by gas chromatography/mass spectrometry (GC/MS). The instrument is built around a miniaturized ITMS system, with a novel direct vapor-sampling inlet and coupled to a high-speed transfer line GC column (short capillary column with fixed pressure drop). The column is temperature controlled inside the standard ion trap transfer line housing. This provides for high-speed analyses at 10-60 s intervals using an automated sampling system constructed with only inert materials in the sample path.

Specific laboratory and field applications exemplify key characteristics of the system including sensitivity, specificity for a broad range of compounds, ruggedness for field-testing in harsh environments, and general speed for field-testing in harsh environments, and general speed and versatility of the analytical technique. The system has been calibrated for alkylbenzenes at concentrations as low as 4 ppb in air and used to monitor these compounds in an office space. Both the MINITMASS and a simpler Ion Trap Detector (ITD) based system have been used to monitor organic vapors from acetone through 5 ring polycyclic aromatic hydrocarbons produced in laboratory scale reactors for studying the thermal desorption and incinerations of hazardous wastes. The ruggedness of the MINITMASS system has been demonstrated by vapor sampling in the Utah summer desert and at a 600 MW coal fired power plant. Finally, the analysis speed and versatility are described for vapor monitoring of volatile organic compounds at an EPA national priority list waste site.

1990

The Chemical Structure and Petrology of Resinite from the Hiawatha "B" Coal Seam

Crelling, J.C.; Pugmire, R.J.; Meuzelaar, H.L.C.; McClennen, W.H.; Huai, H. and Karas, J.
Energy & Fuels, 1990 (In press). Funded by ACERC and US Department of Energy.

Although the maceral resinite occurs in most U.S. coals, it is particularly abundant in the coal seams of the Wasatch Plateau coalfield in central Utah. The high resinite content of the coals of central Utah has long been known and commercially exploited but little work has been reported on the elucidation of the chemical composition of this material. Details of the chemical structure of the micropetrographically defined maceral resinite have generally been lacking because it is noncrystalline and is only partially soluble in organic solvents. In contrast with the abundance of spectroscopic and chromatographic data available on some of the better known fossil resin types, e.g., Baltic amber, Utah coal resins appear to have generated relatively little interest among coal scientists. The overall objective of the present study was to examine the structure of Utah Wasatch Plateau coal resinite macerals that have been separated from the coal matrix, purified, and most important, carefully characterized by fluorescence spectral analysis. The samples were then analyzed by means of CP/MAS C NMR and by Curie-point pyrolysis in direct combination with mass spectrometry (Py-MS) or via preseparation by gas chromatography (Py-GC/MS).

Development of Novel, Mass Spectrometric Combustion Monitoring Techniques

McClennen, W.H.; Arnold, N.S.; Sheya, S.A.N.; Lighty, J.S. and Meuzelaar, H.L.C.
Preprints for Papers Presented at the 200th ACS National Meeting, 35 (3), 713-720, Washington, D.C., 1990. Funded by ACERC.

An on-line gas and vapor analysis method has been developed to monitor combustion products by short column ("transfer line") Gas Chromatography/Mass Spectrometry. An automated vapor-sampling inlet with only inert materials (quartz and fused silica) in the sample path is utilized to introduce flue gases into a 1 m long "transfer line" capillary GC column for rapid, repetitive chromatographic separation of products. The column effluent is introduced directly into the source of an ion trap type mass spectrometer. Combustion products from a gas fired rotary kiln were monitored by this method using a standard Ion Trap Detector (ITD). Detection limits of 20 to 50 ppb were obtained for various substituted benzenes. Monitoring of polycyclic aromatic hydrocarbons (PAHs) from the thermal desorption of contaminated soils in a fixed bed reactor utilized a modified Ion Trap Mass Spectrometer (ITMS). Varying isothermal column temperature allowed analysis of PAHs from naphthalene through 6 ring PAHs. The ITMS system provides higher sensitivity (~4 ppb for benzene) in addition to tandem MS and chemical ionization capabilities for unambiguous identification of combustion products incompletely resolved by the transfer line GC approach.

Fast, Repetitive GC/MS Analysis of Thermally Desorbed Polycyclic Aromatic Hydrocarbons (PAHs) from Contaminated Soils

McClennen, W.H.; Arnold, N.S.; Roberts, K.A.; Meuzelaar, H.L.C.; Lighty, J.S. and Lindgren, E.R.
Combustion Science and Technology, 1990 (In press). Sponsored by Remediation Technology, Gas Research Institute, ACERC, Finnigan Corp. and IT Corporation.

A system for on-line analysis of organic vapors by short column gas chromatography/mass spectrometry (GC/MS) has been used to monitor products from a thermal soil desorption reactor. The system consists of a unique air-sampling inlet with a 1-meter long capillary column coupled directly to a modified Ion Trap Mass Spectrometer (Finnigan MAT) with demonstrated detection limits for alkylbenzenes in the low ppb range. In this work the mobile instrument is used for repetitive GC/MS and GC/MS (tandem MS) analysis at 30 to 60 sec intervals of PAH products from coal tar contaminated soils in a bed characterization reactor.

Results for napthalene through dibenzanthracenes are compared to conventional, more detailed GC/MS analyses of extracts from the soil before and after thermal treatment.

A combustion map of burnout values was made using the laboratory nozzle at an A/S of 0.7, swirl number of 1.5 and SR of 1.1.

Rate Limiting Processes in the Rotary-Kiln Incineration of Contaminated Solids

Lighty, J.S.; Eddings, E.G.; Lindgren, E.R.; Deng, X.-X.; Pershing, D.W.; Winter, R.M. and McClennen, W.H.
Combustion Science and Technology, 1990 (In press). Funded by ACERC, Gas Research Institute and Remediation Technology.

A study of transport processes during the desorption of organic and metallic contaminants from solids is being conducted using several fundamental experiments. This paper presents results from three experimental systems, a Particle-Characterization Reactor, Bed-Characterization Reactor, and Metals Reactor.

The organic experiments attempt to identify the controlling transports processes within a particle of soil and through a bed of particles, as well as quantify the necessary parameters to model these processes. Gas and solid-phase speciation data for field samples, soils contaminated with a variety of organics (boiling points from 220ºC to 495ºC), are discussed. The data suggest that local temperature and gas/solid contacting are important in the desorption process. As expected, lighter components desorb faster than the heavier hydrocarbons. Moisture content was also important in the desorption of contaminant.

The metals reactor has been used to determine the fate of metals, specifically the partitioning between the gas and solid, for a metal species on an inert solid matrix. Data from a parametric characterization study of partitioning of lead, in the form of lead oxide on an inert matrix, in different gas environments are presented. The results indicate that lead is most volatile in a dilute hydrogen chloride/nitrogen environment.

Vapor Sampling Device for Direct, Short Column Gas Chromatography/Mass Spectrometry Analyses of Atmospheric Vapors

Arnold, N.S.; McClennen, W.H. and Meuzelaar, H.L.C.
Analytical Chemistry, 1990 (In press). Funded by ACERC.

A number of methods are currently used for atmospheric vapor and gas sampling with mass spectrometric detection and identification. Direct mass spectrometry (MS) sample introduction methods include fixed molecular tasks (1), atmospheric pressure ionization (2,3), trap and desorb (4), and membrane separation (5), while gas chromatography/mass spectrometry (GC/MS) methods employ trap and desorb (6), direct bubbler solvent injection (7,8), sample loops (9), and pressurized gas plug introduction (10). Approaches vary depending upon whether MS, tandem MS, or GC/MS analyses are desired. Direct MS and tandem MS analyses typically give quick response times and high repetition rates but are often sensitive to interference, including atmospheric constituents, while GC/MS analyses offer greater specificity but with typically lower results.

On-Line GC/MS Sampling of Exhaust Gas from a Rotary Kiln Simulator

Lighty, J.S.; Wagner, D.; Deng, X.-X.; Pershing, D.W.; McClennen, W.H.; Sheya, S.A.N.; Arnold, N.S. and Meuzelaar, H.L.C.
AWMA Specialty Conference on Waste Combustion in Boilers and Industrial Furnaces, Kansas City, MO, 1990. Funded by ACERC.

An on-line, short-column gas chromatography/mass spectrometry (GC/MS) system has been used to monitor the evolution of trace amounts of hydrocarbons evolving from a material which has been combusted in a rotary-kiln simulator. The system uses the isothermally heated, 1-m long transfer line of an Ion Trap Detector (ITD) as the gas chromatograph. The fused silica capillary normally used in the transfer line is replaced by a 1 m, 0 .15-mm inside diameter, 1.2 micron thick methyl silicone stationary phase (DB-1) GC column. Given the short column length and using a direct vapor sampling inlet, the exhaust gas can be sampled quickly, approximately every 10 s in these experiments. Since the column is isothermal, only a limited range of compounds can be analyzed for any given experiment.

Progress in CB Detection by Transfer Line GC/MS Using a Miniaturized Ion Trap Mass Spectrometer

Meuzelaar, H.L.C.; Arnold, N.S.; McClennen, W.H. and Snyder, A.P.
Proceedings of the 1989 US Army Chemical Research Development and Engineering Center Scientific Conference on Chemical Defense, 373-379, 1990. Funded by ACERC, US Army Chemical Research Development and Engineering Center, and Finnigan Corp.

A novel direct vapor-sampling inlet has been tested in combination with Transfer Line Gas Chromatography/Mass Spectrometry (TLGC/MS) using the MINITMASS (Miniaturized Ion Trap Mass Spectrometer) system developed at the University of Utah. Typically, 0.2-0.5 s wide air pulses are injected into the 1 m long transfer line at 15-60 s intervals. Even with relatively complex mixtures of vapors, e.g., produced by desorption and combustion of model compounds in a laboratory-scale fixed bed reactor, sufficient GC separation may be obtained to allow positive identification of minor reaction products by direct library search and matching procedures. Moreover, the high sensitivity of the MINITMASS allows tandem MS analysis of subpicogram quantities of selected model compounds.

1989

Laser Pyrolysis Mass Spectrometry of Single Levitated Coal Particles

Maswadeh, W.; Roberts, K.A.; McClennen, W.H.; Meuzelaar, H.L.C. and Arnold, N.S.
37th ASMS Conference on Mass Spectrometry and Allied Topics, Miami Beach, Florida, 304-305, 1989. Funded by ACERC (National Science Foundation and Associates and Affiliates), US Department of Energy, and the State of Utah.

A laser pyrolysis mass spectrometry experiment was designed to study the devolatilization behavior of individual coal particles at high heating rates (104-106 K/s), characteristic of pulverized coal combustion reactors. The experimental set-up consists of an electrostatic particle levitation cell, also known as an "electrodynamic balance", a 50 W cw CO2 laser and a Finnigan-MAT ITMS system. The particle levitation cell was constructed by modifying a regular ion trap electrode assembly in such a way as to provide line-of-sight access to the center of the cell for the CO2 laser beam as well as for visual observation by means of a stereo microscope. Typical cell operating parameters for levitating a 120 mm dia. Spherocarb particle are: ring electrode 3000 V (60 Hz ac), upper end-cap +100 V dc, lower end-cap -100 V dc. The CO2 laser (Apollo 3050 OEM) is capable of electronic pulsed beam operation. The 8 mm dia. beam is split equally into 2 opposing beams focused at the center of the levitation cell (beam waist ca. 400 um, power density ca. 4-10 MW/m2), as a co-linear parfocal HeNe laser beam permits positioning the levitated particle in the optical and electrical center of the cell. Two IR detectors measure the integrated pulse and time-resolved pulse energy.

A heated transfer line column (2m x .18 mm DB5) equipped with a special air sampling inlet enables intermittent sampling of volatiles from the center of the levitation cell into the ITMS vacuum system. Feasibility studies were performed on 120-150 mm Spherocarb particles impregnated with an alkylnaphthalenes mixture and heated with a single 10 ms CO2 laser pulse. Ample signal intensities were obtained with the first laser pulse to permit the recording of "transfer line" GC/MS profiles. By contrast, the second laser pulse produced <10% of the volatiles observed from the first pulse, thereby demonstrating nearly complete devolatilization of the impregnated particle by a single laser pulse.

Finally, a series of experiments was performed with actual coal particles in the 100-130 mm size range, prepared by careful sieving of two coals from the Argonne National Laboratory Premium Coal Sample bank, namely a Pittsburgh #8 seam (Illinois) coal and a Blind Canyon seam (Utah) coal of comparable rank. From previous studies of Pitt. #8 coal using time-resolved Curie-point pyrolysis, pyrolysis temperatures necessary to produce these phenolic building blocks at heating rates of 105 K/sec are estimated to be ca. 900 K. Of course, kinetic parameters obtained at the much lower heating rates of the Curie-point pyrolysis MS experiment (approx. 102 K/s) may only be extrapolated to the laser pyrolysis experiment if the underlying reaction mechanisms are comparable. Evidence supporting this assumption is presented showing similar C1 and C2-alkyl phenol profiles for the Pitt. #8 coal obtained by Curie-point pyrolysis GC/MS using a 15 m fused silica capillary with temperature programming.

Development of a Mobile Ion Trap Mass Spectrometer for Environmental Monitoring

Meuzelaar, H.L.C.; McClennen, W.H.; Arnold, N.S.; Maswadeh, W.; Reynolds, T.K.; Urban, D.T. and Jones, P.R.
Proc. 37th ASMS Conference on Mass Spectrometry and Allied Topics, Miami Beach, Florida, 1424-1426, 1989. Funded by ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, US Department of Energy, the Department of Defense Chemical Research Development and Engineering Center and Finnigan-MAT Corp.

The objective of the work reported here is to develop a compact, mobile mass spectrometer with EI, CI and MSn capabilities. Moreover, the mobile MS system should be capable of analyzing gases, vapors and aerosols in air at low ppb levels while allowing positive identification of individual components in complex mixtures. In view of the size and weight restrictions inherent in the mobility requirement, a special miniaturized version of the Finnigan MAT Ion Trap Mass Spectrometer (ITMS?) was constructed in close collaboration with the manufacturer. This MINITMASS Miniaturized Ion Trap Mass Spectrometer) system is equipped with automatic gain control, automatic reaction control, selective mass storage and axial modulation options, in addition to the required EI/CI and MSn operating modes. The 2x2x2 ft MINITMASS module is mounted within a 6 ft high mobile rack together with all gas supplies, pumps, inlet controls and a PC 80386 workstation. The entire system requires approx. 1000 W of ac power. A 6x7x8 ft, self-contained mobile laboratory module, which fits on a standard 3/4 ton pick-up truck, enables operation of the MINITMASS in remote locations and rugged terrain. Also, the MINITMASS system can be remotely controlled from a distance up to several miles using a second PC workstation, and Carbon Copy© software. A direct air-sampling inlet enables repetitive collection of 10-50 microliter air samples at 15-60 sec intervals. Use of "transfer line chromatography" provides additional resolution and specificity for complex mixtures. Minimum detectable levels of gases and vapors in air are in the low to medium ppb range without the use of concentration devices. Alternatively, a special automated inlet enables electrostatic precipitation of air particulate matter on a ferromagnetic filament with subsequent analysis by Curie-point pyrolysis (GC)/MSn. The system has been successfully operated in the desert (at temperatures up to 100 F), as well as under a variety of indoor conditions, e.g., for monitoring laboratory-scale combustion reactors.

Direct On-Site Vapor Monitoring by Transfer Line GC/MS

Arnold, N.S.; Roberts, K.A.; McClennen, W.H. and Meuzelaar, H.L.C.
Proc. 37th ASMS Conference on Mass Spectrometry and Allied Topics, Miami Beach, Florida, 1424-1426, 1989. Funded by ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, US Department of Energy, the Department of Defense Chemical Research Development and Engineering Center and Finnigan-MAT Corp.

A direct atmospheric vapor sampling inlet has been used for on-line monitoring of vapors in laboratory scale reactors. The inlet consists of three concentric tubes with appropriate flow control plumbing and electronics. This inlet provides for direct introduction of a pulse of air (.5 to 2 s) into a short (1 m) coated fused silica capillary column enclosed in the heated transfer line housing of a Finnigan-MAT ITD. Effluent from the column emerges directly into the ion trap. Data presented here were obtained by sampling from a bed-characterization reactor (for waste disposal studies) using the MINITMASS, a modified mobile Ion Trap Mass Spectrometer. (Alternate sampling environments have included a coal combustor, an open air chemical release, a micro-scale laser pyrolysis chamber, and in-building ambient atmospheres.) Vapor samples were obtained repetitively at 60 s intervals, allowing for an isothermal GC separation of various components. A ~1.5 s vapor sample allowed up to 100 ul (@STP) of reactor atmosphere to enter the transfer line for chromatographic separation. A .18 mm ID transfer line with a .4 um DB-5 coating (J+W Scientific) was operated isothermally at either 25º, 80º or 125ºC. Carrier gas (helium) velocity was -2.7 m/s (at column temp=25ºC and 4400 ft elevation). All analyses were performed using electron impact ionization. Detection limits have been established near the 1 ppb level for various substituted aromatic compounds using this (MINITMASS) system and taking advantage of the Axial Modulation* and Selective Mass Storage* features to improve sensitivity. Estimations of concentration in this presentation are provided from the calibration data obtained on toluene, ethylbenzene, o-, m-, and p-xylene and general sensitivity characteristics of ion trap mass spectrometers for the compounds of interest. In the present analyses, halogen-, nitrogen- and oxygen-substituted aromatics have been detected at <100 ppb. Various column temperatures allowed for analysis of compounds with atmospheric boiling points from 80ºC (benzene) to 350ºC (anthracene) present in reactor vapors. To date, test analyses of high boiling compounds than these have required the reactor be run under nitrogen to prevent rapid column degradation, though compounds as involatile as dibenzanthracenes (bp 550ºC) have been detected under test conditions.

A Mobile, Tandem Ion Trap Mass Spectrometer System for Environmental Monitoring of Vapors

Arnold, N.S.; McClennen, W.H.; Maswadeh, W.; Urban, D.T.; Reynolds, T.K.; Jones, P.R. and Meuzelaar, H.L.C.
Proceedings of the 1989 U.S. Army Chemical Research Development and Engineering Center Scientific Conference on Chemical Defense Research, 1989. Funded by ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, US Department of Energy, the Department of Defense Chemical Research Development and Engineering Center, Geocenter, Inc. and Finnigan-MAT Corp.

A fieldable, Miniaturized Ion Trap Mass Spectrometer (MINITMASS) was constructed for tandem mass spectrometry of environmental vapors. Furthermore, a vapor sampling inlet for transfer line gas chromatography/mass spectrometry was developed which permits direct on-column introduction of atmospheric vapor samples. The transfer line gas chromatography/tandem mass spectrometry combination provided for direct introduction of complex vapor samples with short overall analysis times for on-line monitoring of changing environmental conditions. Work to date has shown the capability for low ppb analysis of substituted aromatic hydrocarbons, corresponding to subpicogram quantities per compound, in MS as well as MS/MS mode.

On-Site Transfer Line GC/MSn Analysis of Environmental Vapors Using a Modified Ion Trap Mass Spectrometer

Arnold, N.S.; McClennen, W.H. and Meuzelaar, H.L.C.
Preprints of Papers Presented at the 198th ACS National Meeting, 29 (2),Miami Beach, Florida, 1989. Funded by ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, US Department of Energy, the Department of Defense Chemical Research Development and Engineering Research Center and Finnigan-MAT Corp.

An air-sampling inlet has been developed for on-column injection of atmospheric vapor samples using transfer line GC/MS analysis. Repetitive sampling at 15 to 60 sec intervals provides for short GC separations of the individual components. On-site GC/MSn analyses have been performed using a modified mobile ion trap mass spectrometer. Sites sampled thus far include a laboratory scale coal combustor, a high temperature soil desorber for hazardous waste disposal studies, an open-air chemical release and in-building ambient atmospheres.

Current detection limits are on the order of 1 ppb for selected compounds. Compounds with boiling points greater than 80ºC (e.g., benzene) can be readily separated with a 1 m DB-5 coated fused silica column. Analyses reported here are primarily aimed at aromatics through benzopyrene including nitrogen-, oxygen- and halogen-substituted compounds.

Progress in CB Detection by Transfer Line GC/MSn Using a Miniaturized Ion Trap Mass Spectrometer

Meuzelaar, H.L.C.; Arnold, N.S.; McClennen, W.H. and Snyder, A.P.
Proceedings of the 1989 US Army Chemical Research Development and Engineering Center Scientific Conference on Chemical Defense Research, 1989. Funded by ACERC (National Science Foundation Associates and Affiliates), the State of Utah, US Department of Energy, the Department of Defense Chemical Research Development and Engineering Center and Finnigan-MAT Corp.

A novel direct vapor-sampling inlet has been tested in combination with Transfer line Gas Chromatography/Mass spectrometry (TLGC/MSn) using the MINITMASS (Miniaturized Ion Trap Mass Spectrometer) system developed at the University of Utah. Typically, 0.2-0.5 s wide air pulses are injected into the 1 m long transfer line at 15-60 s intervals. Even with relatively complex mixtures of vapors, e.g., produced by desorption and combustion of model compounds in a laboratory-scale fixed bed reactor, sufficient GC separation may be obtained to allow positive identification of minor reaction products by direct library search and matching procedures. Moreover, the high sensitivity of the MINITMASS allows tandem MS analysis of subpicogram quantities of selected model compounds.

Development and Testing of a Mobile Tandem Mass Spectrometer for Monitoring Gases, Vapors, and Aerosols

Meuzelaar, H.L.C.; Arnold, N.S.; McClennen, W.H. and Maswadeh, W.
Conference on Environmental Chemistry, Jeckyll Island, Georgia, 1989. Funded by ACERC (National Science Foundation Associates and Affiliates), the State of Utah, US Department of Energy, the Department of Defense Chemical Research Development and Engineering Center, Geocenter, Inc. and Finnigan-MAT Corp.

Recent advances in Ion Trap/Mass Spectrometry (ITMS) technology now enable the assembly of compact ITMS systems with Chemical Ionization (CI) as well as tandem MS (MSn) capabilities. In combination with the proven high sensitivity (full spectra have been recorded on less than 1 pg of sample) and the favorable vacuum characteristics, ITMS devices appear especially well suited for a variety of environmental monitoring tasks.

Based on these assessments, we undertook the development of a mobile Miniaturized Ion Trap Mass Spectrometer (MINITMASS) equipped with specialized air sampling inlets for gases/vapors as well as for aerosols. Both inlet systems employ the so-called transfer line chromatography (TLGC) approach in order to increase specificity and minimize exposure of transfer line, ion source and electron multiplier to oxygen.

Gases and vapors are sampled as 1-2 sec wide air "pulses" at 15-60 second intervals depending on the degree of chromatographic separation required. Minimum detectable concentration levels were found in the low to medium ppb range. The aerosol inlet uses electrostatic precipitation of aerosol particles (0.5-5 um range) on a ferromagnetic filament. After a preselected collection period (e.g., 1-10 minutes) the filament is automatically inserted into a Curie-point pyrolysis reactor with subsequent production of the pyrolysis GC/MS patterns of the collected aerosol particles.

Thus far, the system has been tested with synthetic polymers, biopolymers and bacterial spores.

Monitoring the Evolution of Organic Compounds from the Thermal Treatment of Contaminated Soil Samples Using Short Column GC/MS

McClennen, W.H.; Arnold, N.S.; Lighty, J.S.; Eddings, E.G.; Lindgren, E.R.; Roberts, K.A. and Meuzelaar, H.L.C.
Preprints of Papers Presented at the 198th ACS National Meeting, 34 (3), Miami Beach, Florida, 1989. Funded by the Gas Research Institute, Dave Linz, Project Manager, ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, and US Department of Energy.

Incineration is an effective technology for the remediation of organic chemical contaminated wastes. For solid wastes, such as contaminated soils, processes involving separate stages of a primary desorber and secondary afterburner are particularly useful. The desorption stage is currently being modeled using a particle-characterization reactor (PCR, 0-500 g capacity), a bed-characterization reactor (BCR, 0.5-5 kg), and a rotary kiln simulator (2-15 kg) to study fundamental processes such as mass transfer, heat transfer, and volatilization of contaminants. This paper describes the analytical methods and preliminary results from monitoring the evolution of organic compounds in these and smaller reactors.

The samples are soil contaminated with a broad range of polynuclear aromatic (PNA) hydrocarbons such as those derived from coal tars. The analytical methods primarily involve mass spectrometry (MS) with a variety of sample introduction techniques. The on-going analyses include solvent and thermal extractions of soil before and after various thermal treatments as well as on-line monitoring of vapors during desorption.

Fast, Repetitive GC/MS Analysis of Thermally Desorbed Polycyclic Aromatic Hydrocarbons (PAHs) from Contaminated Soils

McClennen, W.H.; Arnold, N.S.; Roberts, K.A.; Meuzelaar, H.L.C.; Lighty, J.S. and Lindgren, E.R.
1st International Congress on Toxic Combustion, 1989. Funded by Remediation Technologies, the Gas Research Institute, ACERC (National Science Foundation and Associates and Affiliates), the State of Utah, and US Department of Energy.

A system for on-line analysis of organic vapors by short column gas chromatography/mass spectrometry (CG/MS) has been used to monitor products from a thermal soil desorption reactor. The system consists of a unique air-sampling inlet with a 1 meter long capillary column coupled directly to a modified Ion Trap Mass Spectrometer (Finnigan MAT) with demonstrated detection limits for alkylbenzenes in the low ppb range. In this work the mobile instrument is used for repetitive GC/MS and GC/MSn (tandem MS) analysis at 30 to 60 sec intervals of PAH products from coal tar contaminated soils in a bed characterization reactor.

Results for naphthalene through dibenzanthracenes are compared to conventional, more detailed GC/MS analyses of extracts from the soil before and after thermal treatment.

1988-1987

Pyrolysis Short-Column GC/MS Using the Ion Trap Detector (ITD) and Ion Trap Mass Spectrometer (ITMS)

Richards, J.M.; McClennen, W.H.; Bunger, J.A. and Meuzelaar, H.L.C.
Finnigan Application Note, (214), 1988. Funded by Finnigan MAT.

The results in this report show the capabilities of a short column equipped with a flash pyrolysis/evaporation inlet and interfaced directly to an ITD. The system has proven to be capable of rapid analysis of complex natural and synthetic materials, with relatively little loss in resolution relative to longer columns.

The Chemical Structure and Petrology of Resinite from the Hiawatha "B" Coal Seam

Crelling, J.C.; Pugmire, R.J.; Meuzelaar, H.L.C.; McClennen, W.H. and Karas, J.
Submitted to Coal Geology, 1987. Funded by ACERC (National Science Foundation and Associates and Affiliates).

Although the maceral resinite occurs in most US coals, it is particularly abundant in the coal seams of central Utah. The high resinite content of the coals of central Utah has long been known and commercially exploited but little work has been reported on the elucidation of the chemical composition of this material. Indeed, there is little such information on the resinite of any coal. The resinite occurrences have been described by Spieker and Baker, Tomlinson, Theissen and Sprunk, and Buranek and Crawford. An unusual feature of the coal seams in Utah is that most of the resinite occurs in a secondary manner as cleat, fissure, or other void fillings. Similar occurrences have been reported in British coals by Jones and Murchison and Murchison and Jones. They concluded that the metamorphic effects of coalification in the bituminous rank range caused the resinite to be gently mobilized without the more severe manifestations of metamorphism such as vesiculation or increased refectance. Teichmuller, observed that secondary resinite (exudatinite) seemed to be exuded from other coal macerals during coalification in the lower bituminous range.

Entrained gasification tests with a Utah high-volatile bituminous coal were performed at atmospheric pressure to assess the influence of particle size, coal feed rate, steam-coal ratio and oxygen-coal ratio. Independent argon-carbon balanced and ash balance methods were used to evaluate carbon conversion, with good agreement observed between the methods. A higher O2-coal ratio for finer particles increased the carbon conversion. Carbon conversion and hydrogen formation showed little dependence on the amount of steam injected in the secondary stream, indicating minimal steam-coal reaction. When the coal feed rate was varied from 23 to 27 kgh-1, a small increase in carbon conversion was observed with no significant change in the gas composition.

Determination of Fractional Concentrations and Exact Component Spectra by Factor Analysis of Pyrolysis Mass Spectra of Mixtures

Windig, W.; McClennen, W.H. and Meuzelaar, H.L.C.
Chemometrics and Intelligent Laboratory Systems, 1, 151-165, 1987. 14 pgs. Funded by US Air Force, Army Research Office and BF Goodrich.

Factor analysis of the "correlation around the origin" matrix as applied to (pyrolysis-) mass spectrometry data is described. This approach makes it possible to calculate the spectra of pure components from a data set of mixtures in which these pure components are not present. Further, the fractional concentrations of the components in the mixtures can be calculated. Examples are given of results obtained on data sets consisting of (pyrolysis) mass spectra from biopolymers, jet fuels and technical polymers.

The Role of Aliphatic and Aromatic Coal Structures and Macerals in Low-Temperature Oxidation Processes

Yun, Y.; Jakab, E.; McClennen, W.H.; Hill, G.R. and Meuzelaar, H.L.C.
ACS Preprints, 32, (1), 1987, Denver, CO. Funded by US Department of Energy.

Low temperature (<100ºC) coal oxidation processes are known to have a pronounced effect on important coal properties such as coking and caking behavior, heat of combustion, floatability, slurry pH, tar yield and extractability. However, the mechanisms and kinetics of the chemical reactions underlying such weathering processes in coal are far from well understood. In this article new Py-MS data on low temperature oxidation effects in several US coals of different rank and origin will be discussed with special emphasis on the role of different coal macerals.