Simultaneous analysis of sulfolane and BTEX in rock samples by gas chromatography–mass spectrometry
Bibliographic record
Abstract
• Sulfolane is a stable, mobile industrial solvent with environmental concerns. • BTEX are frequently present at sites contaminated with sulfolane. • A GC-MS method with microwave-assisted extraction was optimized for rapid analysis. • Method reproducibility, recovery, and sulfolane stability in methanol were confirmed. • The method was applied to 109 field-derived rock samples from Alberta, Canada. Sulfolane is a water-miscible industrial solvent that has been widely utilized in various industries. Once released into the environment, it can infiltrate fractured rock structures in groundwater zones, leading to long-term contamination. Benzene, toluene, ethylbenzene, and xylenes (collectively known as BTEX) are commonly associated with sulfolane in the petrochemical industry. The presence and mobility of sulfolane can influence the distribution and transport behavior of BTEX at contaminated sites. Therefore, simultaneous analysis and monitoring of these compounds are crucial for understanding the source and fate of contamination. In this study, a gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the simultaneous quantitation of sulfolane and BTEX in rock samples. To address the slow release of sulfolane observed in certain samples when left in methanol and to facilitate rapid analysis, a microwave-assisted extraction (MAE) method was optimized for sample preparation. Analysis of spiked samples yielded recoveries of 86% to 115% for the various analytes, with relative standard deviations of up to 7.9%. The validated method was then applied to rock samples collected from a contaminated site in central Alberta, Canada. All analyzed samples were contaminated with toluene. Only one sample was found to be contaminated with sulfolane. Ethylbenzene, o- xylene, m / p- xylene, and benzene, were detected in 82%, 44%, 40%, and 4% of the samples, respectively. Although the concentrations of these contaminants were all below the Alberta Tier 1 Soil Remediation Guidelines, the sampling covered only a limited depth. Therefore, additional sampling and investigation are necessary to conclusively determine the status of persistent contamination at the site.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".