Grantee Research Project Results
Final Report: New Chemical Analysis Tools for Aromatic Hydrocarbons
EPA Grant Number: R829415E02Title: New Chemical Analysis Tools for Aromatic Hydrocarbons
Investigators: Campiglia, Andres D. , Swenson, Orven F. , Borgerding, Anthony J.
Institution: North Dakota State University Main Campus , University of North Dakota
EPA Project Officer: Chung, Serena
Project Period: September 1, 2001 through August 31, 2003 (Extended to February 28, 2005)
Project Amount: $499,105
RFA: EPSCoR (Experimental Program to Stimulate Competitive Research) (2000) RFA Text | Recipients Lists
Research Category: EPSCoR (The Experimental Program to Stimulate Competitive Research)
Objective:
Our Science and Engineering Environmental Research (SEER) project was a focused, multidisciplinary, multi-institutional approach to developing new analysis methodology for an important class of organic contaminants: the aromatic hydrocarbons. Specifically, the research proposed in the SEER section led to improved methodology for the selective chemical analysis of polycyclic aromatic hydrocarbons (PAHs), the BTEX compounds (benzene, toluene, ethylbenzene, and the xylenes), and the halogenated benzene compounds.
Summary/Accomplishments (Outputs/Outcomes):
Dr. Borgerding funded four undergraduate students who performed various projects related to the aromatic selective laser ionization detector (ArSLID). These projects included studies to determine the degree of improvement in selectivity and sensitivity offered for aromatic compounds with various substituent groups. A new gas chromatography (GC) detector was created that is comparatively sensitive and far more selective for aromatic compounds than the traditional photoionization detector. The detection means is multiphoton ionization at atmospheric pressure. The ionization source in these experiments is a diode-pumped passively Q-switched microchip laser operating at 266 nm. Experiments were conducted with the detector interfaced to a fast gas chromatograph. For less than 20 second elution time, limits of detection were less than 1 pg for toluene, ethylbenzene, xylenes, and isopropylbenzene; the limit of detection for benzene was approximately 10 pg. Detector response was linear over five orders of magnitude, including these low levels. Negligible signals were observed for nonaromatic ketones, aldehydes, ethers, and cycloalkanes at levels as high as 0.1 μg (10 mg/L concentration). Detector efficiency after fast GC separation was 0.002 percent when using a detector cell with a radius of 1.1 cm and a purge gas flow of 500 mL/min. The advantages of this detector are further illustrated by the fast GC analysis of fuel samples.
In addition, Dr. Borgerding’s research group redesigned and built a second version of the detector to improve performance. Specifically, the new detector has a higher maximum temperature because they eliminated any connections made with low temperature adhesives and replaced them with screws and ceramics. Furthermore, the new detector is more efficient because the ionization cell volume has been minimized by a factor of 100, resulting in a lower purge gas requirement and a shorter flight path for ions. All of this should result in a detector that is not only more sensitive, but is also more robust.
A method for the analysis of dibenzo[a,1]pyrene in HPLC fractions and water samples has been developed by Dr. Campiglia. Their studies provide the analyst with the following information:
- Spectral characteristics of dibenzo[a,1]pyrene and its isomers at 77 K and 4.2 K in n-octane. They also show that dibenzo[a,1]pyrene can be determined in the presence of the other dibenzopyrene isomers at concentration ratios lower than 1:100.
- Chromatographic retention times for the five dibenzopyrene isomers under the U.S. Environmental Protection Agency (EPA) 550.1 method of analysis. Based on this parameter, they identified the potential interferents among the 16 EPA-PAH. They demonstrate that the co-eluted EPA-PAH do not interfere in analysis of dibenzo[a,1]pyrene by laser-excited time-resolved Shpol’skii spectroscopy (LETRSS).
- Analytical figures of merit (linear dynamic ranges for calibration curves and limits of detection) for the HPLC method (UV-vis and fluorescence detection) and for LETRSS. They demonstrate that LETRSS provides an improvement of at least two orders of magnitude in the limits of detection of the five dibenzopyrene isomers.
- Two procedures for interfacing LETRSS with HPLC analysis.
Dr. Swenson conducted work with the Fast GC interfaced with a laser ionization detector (LID). Initially, the gas flow from the Fast GC was passed through the apex of a half cylinder electrode so that the eluent intersected the laser at right angles. The emitted analyte is in a concentrated gas pulse compared to the ambient levels present in the detector half cylinder. The initial approach was to have the laser beam selectively ionize the aromatics in the concentrated pulse before it dispersed in the open half cylinder. With the open half cylinder, it was found that ambient conditions such as relative humidity, air currents in the room, and temperature affected the waveforms and made it impossible to determine if the shifts were to the result of differences in ion mobility or the other variables.
A new detector was designed and machined with a smaller half cylinder from a block of aluminum. To minimize the effects of ambient conditions on the detector, the new cell was enclosed and uniformly heated. The new detector cell performed significantly better than the previous half-cylinder detectors.
A Synoptics microlaser that operates at 8 kHz was integrated with the Fast GC. At 8 kHz, the waveforms overlap so that there is no additional information produced by capturing the waveforms individually. A standard GC FID was successfully interfaced with the half-cylinder detector without additional amplification of the signal. A cocktail of five aromatics (benzene, toluene, ethylbenzene, orthoxylene, and isopropylbenzene) was successfully separated in a 30 second elution from the fast GC and detected with the LID.
Journal Articles on this Report : 4 Displayed | Download in RIS Format
Other project views: | All 6 publications | 6 publications in selected types | All 6 journal articles |
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Type | Citation | ||
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Arruda AF, Goicoechea HC, Santos M, Campiglia AD, Olivieri AC. Solid-liquid extraction room temperature phosphorimetry and pattern recognition for screening polycyclic aromatic hydrocarbons and polychlorinated biphenyls in water samples. Environmental Science and Technology , 2003; 37(7): 1385-1391. |
R829415E02 (2003) R829415E02 (Final) R828081E01 (Final) |
not available |
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Arruda AF, Yu S, Campiglia AD. Shpol’skii spectroscopy at the interface of two non-polar microenvironments: a novel approach for the analysis of polycyclic aromatic compounds. Talanta 2003;59(6):1199-1211. |
R829415E02 (Final) |
not available |
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Bystol AJ, Campiglia AD. Fluorescence line narrowing spectroscopy of polycyclic aromatic hydrocarbons on solid-liquid extraction membranes. Applied Spectroscopy 2003;57(6):697-702. |
R829415E02 (Final) |
not available |
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Meyer MJ, Schieffer G, Moeker EK, Broderson J, Swenson O, Borgerding AJ. Selective detection of volatile aromatic compounds using a compact laser ionization detector with fast gas chromatography. Analytical Chemistry , 2004; 76(6): 1702-1707. |
R829415E02 (2003) R829415E02 (Final) |
not available |
Supplemental Keywords:
water, drinking water, watersheds, groundwater, exposure, risk, chemicals, VOC, PAHs, solvents, organics, environmental chemistry, monitoring, analytical, measurement methods,, RFA, Scientific Discipline, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Environmental Chemistry, Ecosystem/Assessment/Indicators, Ecosystem Protection, State, Ecology and Ecosystems, Environmental Engineering, Ecological Indicators, monitoring, ecoindicator, ecological exposure, hydrocarbon, VOCs, PAH, BTEX, estuarine ecoindicator, North Dakota (ND)Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.