Fingerprinting Crude Oils and Tarballs using Biomarkers and Comprehensive Two-Dimensional Gas Chromatography

Author(s): Michelle Misselwitz, Jack Cochran, Chris English, and Barry Burger
Restek Corporation

Published By: Restek Corporation

Year of Publication: 2013


Abstract: Petroleum biomarkers are “molecular fossils” that can be analyzed with gas chromatography to fingerprint crude oil. Fingerprints can then be used to determine the source oil for an oil spill or highly weathered tarballs. This unique fingerprint is developed by evaluating several ratios of key biomarkers, such as steranes and hopanes. Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) was used to evaluate biomarker ratios in several crude oils from various regions and also in tarballs that washed ashore on the gulf coast of Florida up to a year after the Deepwater Horizon oil spill of 2010. While one-dimensional GC-MS is often used for this analysis, the power of GCxGC provides enhanced specificity and peak capacity with increased resolving power that can separate diagnostic biomarkers from potential isobaric interferences. Also, GCxGC provides a structured chromatogram, which allows compound identification that would be impossible with GC-MS due to the complexity of crude oil. In this study, using 43 different biomarker ratios from GCxGC-TOFMS analysis, we identified one tarball from a Florida beach that was a possible match to oil from a broken riser pipe collected via an underwater robot during the Deepwater Horizon oil spill. Others were considered non-matches.

Restek Employee-Owners and Customers Partner With the American Red Cross

Red Cross RecognitionRestek Corporation is grateful to have been recognized by the American Red Cross for our efforts to aid the victims of Superstorm Sandy. Through a modification of our Wizard Dollars program that included a one-for-one corporate match, Restek employee-owners and customers donated $2,632 to benefit the American Red Cross Disaster Relief Fund. With such wide-spread destruction after the hurricane, we felt obliged to do what we could to help and wanted to extend the chance to lend a hand to our customers, who graciously responded in large numbers. Restek sincerely thanks the Red Cross for their acknowledgment as well as our customers for the additional support.

With the devastating tornadoes in Oklahoma, we feel compelled to again do our part. Donations are already pouring in from across Restek, and we have also made it possible once more for our customers to give the Wizard Dollars they earn on chromatography purchases to the cause. For two months, customers can simply click a box during checkout asking Restek to convert their Wizard Dollars into cash to help those in need—and we will match donations dollar for dollar up to $5,000. Together, we can try to make a difference to families who have lost so much.

On a related note, we would be remiss if we did not also mention our LC Accessories Product Marketing Manager: Carrie Sprout. For almost all of her 17 years with Restek, Carrie has coordinated our blood drive program, and she was recently honored with the 2013 Business Sponsor Coordinator Award for her hard work and dedication. Congratulations, Carrie!

Accurately Detect and Quantify 204 Pesticides of Global Food Safety Concern by LC-MS/MS

Restek LC-MS/MS Multi-Residue Pesticide KitStop spending your time and money developing LC-MS/MS multi-residue pesticide methods and mixing reference standards when you could be running samples! Restek’s trusted food safety experts have already done the work for you—with guaranteed accuracy and at a lower cost.

Restek’s new certified reference materials (CRMs) for LC-MS/MS multi-residue pesticide analysis eliminate the need to source, purchase, and store individual materials along with the need to prepare your own mixes. Choose separate ampuls for mix-and-match customization or a complete kit that contains 204 compounds of interest, covering many LC-determined pesticides listed by government agencies. Designed for maximum shelf life, stability, and chromatographic performance, each standard ships with support documentation detailing Restek’s rigorous in-house quantitative testing. They even offer an optimized multi-residue pesticide method—including conditions and downloadable transition tables—free of charge.

Set up, verify, and validate your pesticide-screening methods in less time, with proven confidence, and at a significantly reduced cost by turning to Restek’s ISO-accredited labs for your LC-MS/MS multi-residue pesticide certified reference materials. For added convenience and unbeatable results, also consider their internal standards, Ultra and Pinnacle® DB LC columns, and Q-sep™ QuEChERS sample prep products.

Learn more at

Whole Air Canister Sampling and Preconcentration GC-MS Analysis for pptv Levels of Trimethylsilanol in Semiconductor Cleanroom Air

Author(s): Jason S. Herrington
Restek Corporation

Published By: Restek Corporation

Year of Publication: 2013


Abstract: The costly damage trimethylsilanol (TMS) in cleanrooms exacts on scanner lenses in the semiconductor industry has resulted in the demand for accurate and reliable methods for measuring TMS at trace levels (i.e., parts-per-trillion, volume-per-volume of air [pptv] [~ng/m3]. This study developed a whole air canister-based approach for field sampling trimethylsilanol in air, as well as a preconcentration gas chromatography–mass spectrometry (GC-MS) laboratory method for analysis. Results demonstrate clean canister blanks (0.06 pptv [0.24 ng/m3], which is below detection limit [BDL]); excellent linearity (a calibration relative response factor [RRF] relative standard deviation [RSD] of 9.8%) over a wide dynamic mass range (1.0 to 100 pptv); recovery/accuracy of 93%; a low selected ion monitoring (SIM) method detection limit (MDL) of 0.12 pptv (0.48 ng/m3); replicate precision of 6.8% RSD; and stability (84% recovery) out to four days of storage at room temperature. These performance levels should meet the demands of the semiconductor industry for monitoring trace levels of trimethylsilanol in cleanrooms.

Register Today: 2013 INEF Penn State Conference on Environmental Forensics

The International Network of Environmental Forensics (INEF), a non-profit interest group within the Royal Society of Chemistry (RSC), is now finishing preparation for its 2013 conference. After stops in Calgary in 2009 and Cambridge in 2011, the third gathering of this biannual event will be held at The Pennsylvania State University from June 10 through June 12, 2013.

Program Chair Frank Dorman has lead a top-notch team in creating an agenda that will include a day-long short course and plenary presentations as well as oral and poster technical presentations. Jack Cochran, Restek’s Director of New Business & Technology, is a member of both the organizing and program committees, and he will also be speaking along with other Restek chemists. Attendees can expect to learn from internationally recognized experts who are currently practicing and/or studying in the field of environmental forensics. As defined by the INEF, “environmental forensics is the use of scientific techniques to identify the source, age, and timing of a contaminant into the environment.”

The submission deadline for abstracts has passed, but registration is still open. Those with real-world experience in environmental forensics are especially encouraged to attend, as are students looking to pursue studies in environmental forensics. In addition to the full technical program, student submissions will be judged, with the top three winning $1,000, $500, and $250 (U.S.) as part of INEF’s student outreach program. All accepted students will also have the option of publishing their work with the RSC.

Click here for additional details about this exciting conference. To register, visit the INEF website at  And if you have questions, feel free to contact Dr. Frank Dorman at directly.

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QuEChERS: Beyond the Basics

Author(s): Julie Kowalski and Jack Cochran
Restek Corporation 

Published By: Separation Science

Issue: vol. 5, issue 4

Year of Publication: 2013


For the full print issue, visit

Abstract: QuEChERS is a sample preparation approach that was designed to be easy, cheap but effective and rugged at the same time. It is most often used for pesticide residue analysis but its beneficial features have assisted it in branching to other fields such as environment, bioanalytical and clinical. QuEChERS was originally designed for fruits and vegetables and proven to work especially well for high water content fruits and vegetables (>80 %) with slightly acid pH (5–6). However, there are commodities that don’t fit into this food type. Adjustments to the typical QuEChERS procedures extend its usage outside of these typical or easy commodities. Common examples include very acidic food like citrus fruits and fatty foods like avocado, milk and oils.