Analysis of Petroleum Metabolites in Groundwater Using GCxGC-TOFMS
Oral Presentation
Prepared by R. Mohler1, S. Ahn2, K. O'Rielly2, D. Zemo3, A. Tiwary4, R. Magaw5, C. Espino Devine5
1 - Chevron Energy Technology Company, 100 Chevron Way, 50-1271, Richmond, CA, 94801, United States
2 - Exponent, 15375 30th Pl SE, Bellevue, WA, 98007, United States
3 - Zemo & Associates, 986 Wander Way, Incline Village, NV, 89451, United States
4 - Chevron Energy Technology Company, 3901 Briarpark , Houston, TX, 77042, United States
5 - Chevron Energy Technology Company, 6001 Bollinger Canyon Rd, San Ramon, CA, 94583, United States
Contact Information: rmohler@chevron.com; 510-242-4939
ABSTRACT
It is well understood that petroleum hydrocarbons biodegrade to oxygenated compounds such as organic acids. These oxygenated compounds, i.e., metabolites, can be extracted from soil or groundwater samples with dichloromethane and quantified as total petroleum hydrocarbons (TPH) unless they are removed prior to analysis on the gas chromatograph (EPA Method 8015). Silica gel cleanup, EPA Method 3630, will effectively remove the metabolites from the extract, however, there is hesitancy accepting the use of silica gel cleanup because the unknown nature and toxicity of these metabolites produced during the biodegradation process. Because of these questions, a research grade technology, comprehensive two-dimensional chromatography with time of flight mass spectrometry (GCxGC-TOFMS) was used to better characterize the metabolites extracted from groundwater samples along with the petroleum hydrocarbons when using EPA Method 3510. GCxGC-TOFMS tentatively identified more than 1,300 unique metabolites in the groundwater collected at five fuel terminals and five fuel marketing stations. These metabolites were grouped by compound classes including: organic acids and esters, alcohols, ketones, aldehydes, and phenols. This presentation will describe the analytical method used for the detailed analysis and will give insight into the identification of compounds removed by silica gel cleanup of EPA Method 3510 dichloromethane extracts.
Oral Presentation
Prepared by R. Mohler1, S. Ahn2, K. O'Rielly2, D. Zemo3, A. Tiwary4, R. Magaw5, C. Espino Devine5
1 - Chevron Energy Technology Company, 100 Chevron Way, 50-1271, Richmond, CA, 94801, United States
2 - Exponent, 15375 30th Pl SE, Bellevue, WA, 98007, United States
3 - Zemo & Associates, 986 Wander Way, Incline Village, NV, 89451, United States
4 - Chevron Energy Technology Company, 3901 Briarpark , Houston, TX, 77042, United States
5 - Chevron Energy Technology Company, 6001 Bollinger Canyon Rd, San Ramon, CA, 94583, United States
Contact Information: rmohler@chevron.com; 510-242-4939
ABSTRACT
It is well understood that petroleum hydrocarbons biodegrade to oxygenated compounds such as organic acids. These oxygenated compounds, i.e., metabolites, can be extracted from soil or groundwater samples with dichloromethane and quantified as total petroleum hydrocarbons (TPH) unless they are removed prior to analysis on the gas chromatograph (EPA Method 8015). Silica gel cleanup, EPA Method 3630, will effectively remove the metabolites from the extract, however, there is hesitancy accepting the use of silica gel cleanup because the unknown nature and toxicity of these metabolites produced during the biodegradation process. Because of these questions, a research grade technology, comprehensive two-dimensional chromatography with time of flight mass spectrometry (GCxGC-TOFMS) was used to better characterize the metabolites extracted from groundwater samples along with the petroleum hydrocarbons when using EPA Method 3510. GCxGC-TOFMS tentatively identified more than 1,300 unique metabolites in the groundwater collected at five fuel terminals and five fuel marketing stations. These metabolites were grouped by compound classes including: organic acids and esters, alcohols, ketones, aldehydes, and phenols. This presentation will describe the analytical method used for the detailed analysis and will give insight into the identification of compounds removed by silica gel cleanup of EPA Method 3510 dichloromethane extracts.
