Revealing minor terpane biomarkers in lubricants and soils using the customized cleanup method

• Published in: Journal of soils and sediments Vol. 18; no. 1; pp. 136 - 147
• Main Authors: Kao, Nien-Hsin, Su, Ming-Chien, Chang, Chun-Chin, Yen, Chih-Chun
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2018; Springer Nature B.V
• Subjects: Biomarkers; Detection; Dilution; Dry weight; Earth and Environmental Science; Environment; Environmental cleanup; Environmental Physics; Filter paper; Gas chromatography; Identification; Lubricants; Lubricants & lubrication; Mass spectrometry; Mass spectroscopy; Methods; Molecular weight; n-Hexane; Oils & fats; Pollution control; Probability theory; Procedures; Quantitation; Ratios; Sec 3 • Remediation and Management of Contaminated or Degraded Lands • Research Article; Silica; Silicon dioxide; Soil; Soil contamination; Soil Science & Conservation; Soil surfaces; Soils; Weathering; Petroleum biomarker; Surrogate standard; Cleanup; Terpane; Lubricant
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-017-1723-3

Purpose Lubricant oils are popularly applied and the spill incidents are seen ubiquitously in the environment, in which the terpane biomarkers are the most abundant compounds and which are the essential compounds in the contaminated soils. We studied the traditional and modified cleanup protocols and developed a negative pressure cleanup device and proposed a more suitable internal standard in the quantitation of biomarkers, wherein the main terpane compounds in a lubricant and soil samples were identified. Materials and methods Surface soil samples were collected in an oil dispatch center where no major spill accidents have been reported in the past decades. Soil samples were studied based on their dry weight quantity and then extracted by using a microwave digestion system. The extracted sample solution was placed in a filter paper and eluted with n-hexane three times and then concentrated by using a nitrogen purge concentration workstation to 1 mL. A lubricant sample was taken without the step of extraction, 0.1 g of lubricants was diluted with 10 mL of hexane, spiked with the surrogate standard, and then concentrated to 1 mL before silica column cleanup procedures. The characteristic fragment ions of terpanes were determined by m / z 177 and 191 in the gas chromatography mass spectrometry (GC/MS) analysis. Results and discussion In the lubricant sample, besides the 17 dominated compounds, another 20 minor terpanes with a concentration ratio (individual/total) of below 1% were also identified using the modified method. In the soil sample study, the result shows that the quantified major terpane concentrations can be increased up to five times by using the modified method. The soil data also shows that the lower molecular weight compound has higher concentration ratios than the other compounds that were eluted at a later time. The results indicated that for the real environmental samples as for the studied soil, the modified method could enhance the detection probability for those weathering effected compounds. Conclusions The modified cleanup method has successfully improved the identification technology and many overlooked minor biomarkers were revealed in the samples and the minor biomarkers may including the compound that has been popularly used as the surrogate standard. In quantitation, we proposed a more proper internal standard for future research. The results can also be applied to identify other kinds of biomarkers to plan a suitable remediation program for a contaminated site.