Grantee Research Project Results
Final Report: Remote Sampling Probe with Fast GC/MS Analysis: Subsurface Detection of Environmental Contaminants
EPA Grant Number: R826184Title: Remote Sampling Probe with Fast GC/MS Analysis: Subsurface Detection of Environmental Contaminants
Investigators: Robbat, Albert , Gorshteyn, Alexander , Katayenko, Zunovi , Smarason, Sigurdur
Institution: Tufts University
EPA Project Officer: Aja, Hayley
Project Period: February 16, 1998 through February 15, 2001
Project Amount: $305,234
RFA: Exploratory Research - Environmental Chemistry (1997) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Air , Safer Chemicals
Objective:
Reports indicate that the total amount of money spent on investigating and cleaning the nation’s hazardous waste sites is more than $28 billion. Much of the cost centers on collecting samples from the site, analyzing them, and then determining the nature of the contamination and the remedy. Long-term chemical monitoring adds to final site cleanup costs. Traditional sample collection and analysis programs rely on collecting subsurface samples and sending them offsite for analysis. This process is "static." It results in multiple trips to the field until sufficient information is obtained to answer the scientific and engineering questions under investigation. In contrast, if samples can be collected and analyzed in the field quickly enough to impact the decisionmaking process, then the time and cost of evaluating and cleaning hazardous waste sites should be greatly reduced. The objective of this research project was to develop tools that will make this process more "dynamic" by thermally extracting soil-bound organics and transporting them to the surface for analysis. The goal was to collect and analyze volatile and semivolatile organic contaminants (VOCs and SVOCs) onsite, as near to real-time as possible, by fast gas chromatography/mass spectrometry (GC/MS).
Figure 1. Cone Penetrometer.
Summary/Accomplishments (Outputs/Outcomes):
Seventy and 100-ft thermal extraction cone penetrometer (TECP) probes have been built and tested for electrical, mechanical, and chemical stability1. We have determined the mass balance and TECP thermal extraction efficiency for nearly all EPA method 8270 and 8260 targeted SVOCs and VOCs2,3. Findings show that these compounds can be thermally extracted, collected, and analyzed within the recovery range prescribed by EPA. For soils that contain < 20 percent water, VOCs and SVOCs can be collected in 5 min. When the soil-water content is between 20 percent and 30 percent, 15 minutes are needed to obtain the same quality data. The latter compares favorably with cone penetrometers or Geoprobes when used conventionally to bring soil samples to the surface. On the other hand, sample preparation time prior to analysis is virtually eliminated by the TECP, because it delivers organics in a state ready-made for analysis. In contrast, soil brought to the surface must be dried, solvent-extracted, and fractionated by gel permeation before analysis. Also, the TECP collection system is capable of capturing VOCs and SVOCs separately or simultaneously. Simultaneous analysis of 8270 and 8260 target compounds saves significant time over the traditional EPA methods where each compound class is analyzed separately3.
In the last progress report we described a new ballistically heated thermal desorption (TD) sample introduction system, where the sample collected from the TECP probe was directly introduced into the GC is a 2-step process. First, the hot vapor was freeze-trapped in a glass tube housed in the TECP sample collection chamber. The glass tube was brought to the TD unit, which served as the sample inlet system for the GC. Recently, we succeeded in tying these two devices together so that the TECP is directly attached to the GC/MS4. This allows us to simultaneously collect and analyze subsurface contaminants. Although the figure below illustrates our first set of electronic nose experiments, it suggests that the rate of sample collection and analysis should be at least 10-times faster than the traditional sample collection and analysis processes. For example, 8 consecutive measurements were made for TNT and its synthetic precursors in 7 minutes. Target compounds were desorbed from soil and analyzed in 50 seconds per analysis. The ultrafast GC was capable of separating closely eluting isomers (see mononitrated toluenes), while the IFD algorithms were capable of distinguishing each compound’s unique mass spectra. Measurement precision was 20 percent for this experiment. Although this grant has been completed, we will continue to develop the TECP-TD GC inlet for field-ruggedness and to determine measurement precision and accuracy for the wide range of EPA targeted compounds. An internal/external means of calibrating the instrument will be developed. Further research is needed to determine the quality of the data (e.g., semiquantitative or quantitative), with the initial results produced at better than screening quality data. To our knowledge, no technology exists today that can desorb organics from solids, transport them 70 ft, speciate, and quantify them online.
Figure 2. Direct Measuring TECP-TDGC/MS Collection and Analysis.
Figure 3. Ultrafast GC Separation of Nitrated Aromatics.
We plan to design, build, and test the TECP-GC inlet system for online, simultaneous collection and analysis of VOCs and SVOCs. We will test the reproducibility of the ultrafast, resistively heated GC, with column temperature programming capabilities approaching 100°C/sec as opposed to conventional GC ovens that program at 30°C/min. The GC will operate under ultra fast conditions and be mated to a Hewlett Packard mass spectrometer to provide near to real-time measurements. TECP probe extraction efficiency and collection experiments will be made for the combined system and tested for EPA targeted pollutants. Research will focus on developing an internal/external calibration system that should lead to the production of quantitative data in the field.
References:
Gorshteyn A, Smarason S, Robbat, Jr. A. Speciation of subsurface contaminants by cone penetrometry gas chromatography/massspectrometry. Environmental Science and Technology 1999;33:2474-2480.
Gorshetyn AE, Robbat, Jr. A. Rapid in situ collection and analysis of semivolatile organics by thermal extraction cone penetrometry gas chromatography/mass spectrometry. Field Analytical Chemistry and Technology 2000;4:85-92.
Gorshetyn AE, Robbat, Jr. A. An electronic nose by thermal extraction cone penetrometry and ultrafast gas chromatography/mass spectrometry. Analytical Chemistry (submitted, November 2000).
Robbat, Jr. A. Productivity enhancing mass spectral data analysis software for high throughput laboratories: simultaneous detection of volatile and semivolatile organics by GC/MS A. Environmental Testing and Analysis 2000;9:15-19.
Smarason S, Robbat, Jr. A. Optimizing GC separation methods by employing entropy and enthalpy of solution calculations from temperature-programmed retention data. J Chromatography (submitted, October 2000).
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 16 publications | 6 publications in selected types | All 6 journal articles |
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Type | Citation | ||
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Gorshteyn AY, Kataenko Z, Smarason S, Robbat A Jr. Subsurface detection of environmental pollutants. Instrumentation Science and Technology 1999;27(2):111-121. |
R826184 (1999) R826184 (Final) |
not available |
Supplemental Keywords:
soil, in situ analysis, online monitoring, onsite decision making, expedited site characterization, dynamic workplans, green chemistry., RFA, Scientific Discipline, Air, Toxics, Waste, Ecology, Remediation, Environmental Chemistry, Chemistry, HAPS, Hazardous Waste, Hazardous, Engineering, Chemistry, & Physics, Electron Microscopy, thermal extraction, DNAPL, mass spectrometry, subsurface, PCBs, VOCs, Polychlorinated biphenyls (Aroclors), soil screening, gas chromatography, PAH, organic compounds, subsurface detection, analytical chemistry, environmental contaminants, PCB, hazardous chemicals, remote sampling probeProgress 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.