Linda D. Gratz

Interlaboratory comparison of HPLC-fluorescence detection and GC/MS: analysis of PAH compounds present in diesel exhaust.

For laboratories involved in polycyclic aromatic hydrocarbon (PAH) analyses in environmental samples, it is very useful to participate in interlaboratory comparison studies which provide a mechanism for comparing analytical methods. This is particularly important when PAH analyses are routinely done using a single technique. The results are reported for such an interlaboratory comparison study, in which the four selected participating laboratories quantitatively analyzed several PAH compounds in diesel exhaust samples. The samples included particle and vapor phase extracts collected and prepared at Michigan Technological University (MTU PE and MTU VE, respectively), a diesel particle extract prepared by the National Institute for Standards and Technology (NIST, SRM 1975), and a fully characterized diesel particle sample (NIST SRM 1650). One of the laboratories used only HPLC-FLD, one used only GC/MS and two laboratories used both methods for the routine analysis of PAH in environmental samples. Data were obtained for five PAH compounds: fluoranthene, pyrene, benz[a]anthracene, benzo[a]pyrene, and benzo[g, h,i]perylene. The mean PAH levels found for SRM 1650 were outside the range reported by NIST. The range in the reported means was from 24% lower than certified for benz[a]anthracene to 41% higher for benzo[g,h,i]perylene. For the previously uncharacterized samples in this study (SRM 1975, MTU PE and MTU VE), two-thirds of the reported results were higher for the HPLC-FLD method than for the GC/MS. The range in differences between methods was from-54 to+31% calculated as the difference in GC/MS value relative to the HPLC value for each of the compared compounds. Coefficients of variation for the uncharacterized samples appeared to be higher, in most (but not all) cases, for the HPLC-FLD than for the GC/MS. The resolution of certain PAH isomers (e.g. benz[a]anthracene and chrysene, or the benzofluoranthenes), was better, as expected, for HPLC than for GC. Generally lower detection limits (by an order of magnitude or more) were reported for GC/MS than for HPLC-FLD. On the basis of this limited study, it seems as though significant differences may exist between laboratories, if not between methods, in the analysis of certain PAH compounds in real diesel samples by HPLC-FLD compared to GC/MS. If possible, measurements should be made using both methods. This is particularly important where potential interferences are undefined or subject to change, as is frequently the case with real environmental samples.

Physical and chemical characterization of particles in producer gas from wood chips.

Abstract Particles in the gas from a two-stage (separate pyrolysis and gasification) down-draft biomass gasifier were collected and characterized. Their concentration, geometries and chemical compositions were investigated. Special attention was given to features suspected to harm internal combustion (IC) engines fueled by the gas. The implications of the findings on engine wear are discussed. The majority (85%) of the total particulate matter (TPM) mass was identified, using scanning electron microscopy (SEM), as mono-sized spherical primary soot particles with diameters of 70 nm. Soot agglomerates, up to 30 μm were present. 77% of the TPM was determined, by thermogravimetric analysis (TGA) to be carbon structures. The dichloromethane (DCM)-soluble fraction (11% of the TPM) was extracted, separated into fractions of varying polarities using adsorption column chromatography and analyzed using gas chromatography with a flame ionization detector (GC-FID). More than 50% of the soluble mass was relatively non-polar. A well-separated fraction containing 10% of the DCM solubles had significantly higher polarities than the other solubles and/or contained relatively large molecules. Anisole extractions of the particles showed that a 3–7% of the DCM-insoluble TPM was dissolved using this solvent.

Ceramic Particulate Traps for Diesel Emissions Control - Effects of a Manganese-Copper Fuel Additive

The effect of the use of a manganese-copper fuel additive with a Corning EX-47 particulate trap on heavy-duty diesel emissions has been investigated

Effects of a Ceramic Particle Trap and Copper Fuel Additive on Heavy-Duty Diesel Emissions

This research quantifies the effects of a copper fuel additive on the regulated [oxides of nitrogen (NO{sub x}), hydrocarbons (HC) and total particulate matter (TPM)] and unregulated emissions [soluble organic fraction (SOF), vapor phase organics (XOC), polynuclear aromatic carbons (PAH), nitro-PAH, particle size distributions, and mutagenic activity] from 1988 Cummins LTA10 diesel engine using a low sulfur fuel. Engine was operated at two steady state modes (EPA modes 9 and 11, which are 75 and 25% load at rated speed, respectively) and five additive levels (0, 15, 30, 60, and 100 ppm Cu by mass) with and without a ceramic trap. Measurements of PAH and mutagenic activity were limited to the 0, 30, and 60 ppm Cu levels. The fuel additive had little effect on baseline emissions (without the trap) of TPM, SOF, XOC, HC, or NO{sub x}. The trap reduced TPM from 72 93% compared to baseline, had no effect on NO{sub x}, and reduced HC about 30% at mode 9 with no consistent change at mode 11. 23 refs., 15 figs., 15 tabs.

Underground Coal Mine Air Quality in Mines Using Disposable Diesel Exhaust Filter Control Devices

Abstract As part of a collaborative study with the U.S. Bureau of Mines, inmine studies have been conducted to assess the effects of a low temperature disposable diesel exhaust filter. The mines have been designated as mines R and S in U.S. Bureau of Mines publications. Each mine operated three to four Jeffrey 4110 ramcar haulage vehicles in the test section. The ramcars were equipped with MWM D916-6 diesel engines, rated at 74.6 kW (100 hp), and were operated for 3 days with the disposable diesel exhaust filter and 2 days without in both mines. Average diesel particulate matter control efficiencies, as measured by samplers located on the coal haulage vehicle, were 80 percent in mine R and 76 percent in mine S. Diesel particulate matter average control efficiencies, as measured in the diesel engine tailpipe, were 52 percent for mine R (for two ramcar vehicles) and 86 percent for mine S (for four ramcar vehicles). The air quality index control efficiencies, as measured by samplers located on the coal haula...

Underground Metal Mine Air Quality Measurements to Determine the Control Efficiencies of Combined Catalyzed Diesel Particulate Filter and Oxidation Catalytic Converter Systems

Abstract In-mine studies were conducted as part of a collaborative study with the U.S. Bureau of Mines to assess the effects of diesel emission after-treatment control devices on mine air quality. An oxidation catalytic converter (OCC) was replaced with a combined catalyzed diesel particulate filter (CDPF) and OCC unit in one mine, designated mine Q. In a second mine, designated mine T, the OCC was replaced with a CDPF. In each mine, emissions from one diesel-powered mine vehicle were monitored with the two control configurations. In mine Q, the vehicle studied was an Elphinstone R1500 load-haul-dump vehicle equipped with a Caterpillar 3306 PCTA diesel engine used to move ore from a drawpoint to an ore pass. In mine T the vehicle studied was a Tamrock model 2S-TR1 diesel-hydraulic, roof-bolting jumbo powered by a 61-kW (82-hp) Deutz F6L912W diesel engine, which used diesel power to install roof bolts. Control efficiencies for diesel particulate matter (DPM) concentrations in the vicinity of the mine vehic...