The European Pesticide Residue Workshop starts today, June 25, 2012, in the historical city of Vienna, Austria. This series of conferences runs mainly on the strong efforts of volunteers, including students, one here in Vienna who was kind enough to help me hang six Restek posters today. You can see the titles of the posters at our EPRW landing page; let me know if you would like copies of any of the original works. One of the most interesting ones to me concerns findings for pesticide degradation during hot splitless GC injection of QuEChERS canola seed extracts that was quite unexpected and has not previously been reported in any scientific literature, to my knowledge. This degradation did not occur during GC analysis for the same pesticides in QuEChERS extracts of tobacco, nor did it occur when the canola seed extracts were analyzed using LC-MS/MS (Thanks Sharon!).
Archive for the ‘GCxGC’ Category
Petroleum Biomarkers and Tarballs at the 36th International Symposium on Capillary Chromatography and the 9th GCxGC Symposium
I’d like to invite my colleagues to a preliminary view of an upcoming presentation in Riva del Garda, Italy for the 36th International Symposium on Capillary Chromatography and the 9th GCxGC Symposium. We’ve been working on characterizing tarballs that could have originated from the Deepwater Horizon oil spill in the Gulf of Mexico in 2010. The key to matching a source oil and a tarball that may be highly weathered through water washing, evaporation, biodegradation, etc., is to look at compounds such as steranes and hopanes that are resistant to weathering. To get a flavor for what I’m talking about, check out the steranes and hopanes region for “unmatched” oils below that were analyzed using GCxGC-TOFMS. It’s easy to see the differences here and un-matching is easier than matching, typically, for this oil spill fingerprinting work.
More on the tarballs later…
Jack Cochran, Michelle Misselwitz, Barry Burger, Chris English, Ron Stricek (Restek); Mark Merrick (LECO Corporation)
As mentioned in a previous blog, I was able to attend the 7th International POPs Symposium sponsored by Thermo Scientific at the Auditorium Santa Margherita in Venice, Italy and present work done on GC-HRMS analysis of chlorinated dioxins and furans on the Rtx-Dioxin2. The symposium was a veritable Who’s Who of noted scientists in POPs analysis (by the way, POPs stands for Persistent Organic Pollutants), who gave excellent lectures on their work with POPs. The subject matter for these lectures was wide ranging and included POPs in Venice (an excellent presentation by Stefano Raccanelli [Consorzio Interuniversitario Nazionale,La Chimica per l’Ambiente (INCA), Venice, Italy] ,where the climax was pulling a human skull, a Yorick reference, out of a black cloth bag he had carried on stage!), the German chicken egg incident, sample preparation methods including QuEChERS and automated pressurized fluid extraction/cleanup/evaporation, and GC-MS/MS as a possible supplement/replacement for classical GC-HRMS.
Heidi Fiedler from the United Nations Environment Programme gave a fascinating lecture, “Worldwide POPs monitoring; approaches, implementation and results”, describing the effort to determine multiple POPs (PCBs, chlorinated dioxins and furans, chlorinated pesticides, PFOS/PFOA, PBDEs, etc.) worldwide, including in less developed countries who are just getting environmental analytical programs up and going and sometimes only have GC-ECD, and not any MS capability. Sample types include air (collected through the novel GAPS Network sampling equipment), and
human blood and breast milk. If those matrices weren’t hard enough, throw on top of them, unreliable power in some labs, inability to get samples shipped through, and even political revolution (e.g. Egypt). Those are real challenges! A later presentation by Professor Bert van Bavel from Örebro University in Sweden, “Quality assurance and quality control on a worldwide scale: results from the UNEP first intercalibration study”, summarized the analytical challenges specifically for that same program as it gets started. The good news was that labs performed very well for dioxin and furan analysis, which Bert attributed to having GC-HRMS (I suspect isotope dilution plays an equally important role). The bad news was that some labs have a long way to go to produce the desired data quality for other analytes. Fortunately for them, they are in good hands with Bert and others, who have a wealth of experience in these types of studies.
As usual when I go to these symposia, my battery is recharged and I go back to my own lab with new ideas and a good perspective for how important analytical chemistry, including chromatography, is to the health of the world and its people.
IXTOC I & Deepwater Horizon both are estimated to have dumped nearly 5 million barrels of oil into the gulf region 1,2. In 2011, a year after the Deepwater Horizon spill heavy oil and tar balls were washing up on the beaches of the gulf coast 3. Tar near where the IXTOC I oil rig sank can still be found by digging a few centimeters into the ocean floor 31 years later 4,5,6.
In 1990 the Oil Pollution Act (OPA) 7 was promulgated under the direction of the National Oceanic and Atmospheric Administration (NOAA) following the Exxon Valdez oil spill in March of 1989. These regulations require a Natural Resource Damage Assessment (NRDA) following a release of oil into the nation’s waterways. Currently NOAA is conducting a NRDA to determine the impact of the Deepwater Horizon oil spill8. There are several NRDA technical working groups (TWGs) assembled to determine; baseline conditions before the oil spill, impacts to plant and animals following the spill, and the current conditions of the marine ecosystem. The trustees are also evaluating impacts from the response, to include use of dispersants.
There are a variety of methods for the determination of weathered crude oils which were presented by Jaap de Zeeuw at Pittcon this year. The poster detailed the analysis and characterization of different crudes for semivolatiles and biomarkers. Tar balls that were collected on the beaches of Florida from the time the oil first appeared were evaluated and compared to reference crude oils. Characterization of these samples was performed using a variety of techniques to include: Simulated Distillation chromatography, gas chromatography mass spectrometry, and multidimensional gas chromatography.
2012 Pittcon Presentation: Characterization of Gulf Region Tar Balls Following the Deepwater Horizon Oil Spill BARRY BURGER, Restek Corporation, Jaap de Zeeuw, Chris English, Jack Cochran, Jim Witford
Poster as presented at show: 2012 Pttcon 1450-6P Tarball Poster FINAL
Print Friendly: Tarball Poster Pittcon HANDOUT
I’ve been fortunate enough to travel in South Africa and see some of its impressive wildlife, including crocodiles in Kruger National Park, the country’s premiere wildlife watching destination. During one of my trips there, a colleague with the South African Police Service, Roger Dixon, was involved in an environmental forensics study to determine why massive crocodile die-offs were happening in the Olifants and Sable Rivers areas of the park. Hundreds of crocodiles were suffering or dead from pansteatitis, a hardening of the body fat such that it becomes unavailable as an energy source when needed during normal metabolism.
Although the problem is complex, pollution from PCBs, chlorinated pesticides, other industrial chemicals, and pharmaceuticals, is a likely contributing factor. Using GCxGC-TOFMS, a technique ideally suited for comprehensive environmental monitoring, Roger recorded approximately 1600 anthropogenic organic compounds in Olifants River water. Additional stressors include increased sediment, restricted water flow, and algal blooms for the Olifants River related to the Massingir Dam operation just upstream in Mozambique.
A collaborative research program, the Consortium for the Restoration of the Olifants Catchment (CROC), is ongoing to investigate the cause of the problem and hopefully slow the disappearance of this sentinel animal from the park ecosystem by improving water quality.
3rd Multidimensional Chromatography and GCxGC Workshop at Ontario Ministry of Environment in Toronto
The 3rd Multidimensional Chromatography and GCxGC Workshop took place at the Ontario Ministry of the Environment (MOE) in Toronto, Ontario, Canada on January 10, 2012. The excellent lecture program was enjoyed by over 150 attendees and is listed below. Restek helped sponsor the workshop, and contributed three speakers this year due to our extensive work with GCxGC.
Eric Reiner at the MOE deserves the bulk of the credit for organizing the current “grass roots” workshop. Having 150 attendees at a word-of-mouth workshop is amazing, and testimony to the heightened interest in multidimensional separations, and Eric’s push for this technique.
The workshop has an interesting history, having started back at the Centers for Disease Control (CDC) in Atlanta, Georgia in 2003 with me (Jack Cochran, LECO), Eric Reiner (MOE), Frank Dorman (Restek), Jef Focant (post doc at CDC at the time), and Don Patterson, Jr (CDC). I had proposed to Robert J Warren, the President of LECO, that we should attempt chlorinated dioxin and furan analysis with the Pegasus 4D GCxGC-TOFMS. His answer (which I heard often during my tenure!): “What are you waiting on, Jack?” I wrote to Don and he readily agreed and offered to host the effort at CDC. Eric brought samples, Frank brought GC columns, Jef set up the instrument, and we all collected data that I processed with ChromaTOF GCxGC software. The results compared very favorably with those obtained by the “gold standard” GC – high resolution mass spectrometry technique that used a magnetic sector instrument and we turned them into the first publication on using GCxGC-TOFMS for dioxin and furan analysis.
J.-F. Focant, E.J. Reiner, K. MacPherson, T. Kolic, A. Sjödin, D.G. Patterson, Jr., S.L. Reese, F.L. Dorman, and J. Cochran. Measurement of PCDDs, PCDFs, and non-ortho-PCBs by comprehensive two-dimensional gas chromatography-isotope dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS). Talanta 63 (2004), 1231.
It was at one of our daily meetings while on site for that first workshop at CDC that Don Patterson, Jr suggested that Eric, Frank, Jef, and I were the “A Team” of GCxGC-TOFMS, a term which has followed the meeting even unto this day, and LECO generously brings notepads and coffee cups and other paraphernalia to the workshop honoring the reference.
If you’d like any of the Restek presentations from the meeting, please drop me a note.
Tadeusz Gorecki , University of Waterloo, Waterloo, ON; GC×GC 20 years later: Where are we now?
Frank Dorman, The Pennsylvania State University, State College, PA ; Realizing the potential of GCxGC: What role does column choice play?
James Harynuk , University of Alberta, Edmonton, AB; Considerations for quantitative trace analysis in GCxGC: a theoretical look
Jef Focant , University of Liege, Liege, Belgium ; GC×GC-TOFMS analysis of mainstream tobacco smoke
John Kucklick, National Institute of Standards and Technology, Charleston SC; Untargeted screening of San Francisco Bay harbor seals for new organohalogen pollutants
Teruyo Ieda, Gerstel, Tokyo, Japan; GCxGC-HRTOF-MS for analysis of Cl-/Br-PAHs in environmental samples
Brian McCarry, McMaster University, Hamilton, ON; Characterization of complex environmental samples using GCxGC-TOF-MS and GC-FT-ICR-MS
Julie Kowalski , Restek Corporation State College, PA; The QuEChERS approach with GC- and GCxGC-TOFMS for determining PAHs in seafood after the Gulf oil spill
Jack Cochran, Restek Corporation, State College, PA; High quality analysis of pesticides in marijuana for medicine using QuEChERS, cartridge SPE cleanup, and GCxGC-TOFMS
Alina Muscalu, Ontario Ministry of the Environment , Ontario, ON; GCxGC-ECD – A year of routine pesticide analysis: Challenges and perspectives
Michelle Misselwitz, Restek Corporation – State College, PA; Enhancing that certain part of the GC x GC anatomy with QuEChERS and cartridge SPE cleanup for pesticides in dietary supplements
Mark Merrick, LECO Corporation, St Joseph, MI; The GCxGC Column Calculator: A tool for GCxGC method development
Sanja Risticevic, Waterloo University, Waterloo ON; In vivo and ex vivo solid phase microextraction in plant metabolomics: New opportunities for direct investigation of biological systems
Sonja Stadler, University of Ontario Institute of Technology, Oshawa, ON; Analysis of synthetic canine training aids by GCxGC-TOFMS
Pete Claise, Waters Corporation, Milford MA; What can 2D UPLC do for you?
David Alonso, LECO Corporation, St Joseph, MI; High performance gas chromatography, time of flight mass spectrometry analysis of persistent organic pollutants
It was recently reported in Food Safety News that the majority of “honey” sold in the United States is not technically honey, because it’s been ultra-filtered to remove all of the pollen. Maybe the honey badger doesn’t really care, but consumers should. Pollen is an essential constituent of authentic honey, and is not effectively removed by ordinary filtering processes. Only by ultra-filtering the product can it be rendered pollen-free. Ultra-filtered honey is to be considered suspect, because in addition to its reputed health benefits pollen provides the traditional basis for tracing honey’s geographic origins. If the pollen’s been removed, then someone is attempting to conceal where the honey really came from.
Pollen analysis is the customary method, but perhaps not the only viable way to ascertain food origin for honey. None other than our own Jack Cochran, while at LECO, co-authored a paper (J Sep Sci) showing the use of GCxGC-TOFMS to characterize volatiles in honey, with findings that illustrate distinct profiles for honey originating from different parts of Europe. The widespread practice of ultra-filtration making traditional authentication methods ineffective, work such as this is vital for assurance of food origin traceability.
I was hoping someone would challenge me on my last post about fingerprinting oil spills through tarballs that might originate from the BP Deepwater Horizon event. I showed a couple of tarball GCxGC-FID chromatograms on Rxi-5ms x Rxi-17Sil MS, which looked quite dissimilar. But could they originate from the same oil spill? It is possible, since weathering of the oil is very important in the appearance of the chromatogram. You have evaporation, dispersion, biodegradation, dissolution, etc., and those can lead to very different chromatographic profiles for ocean-spilled and “original” oils. So what environmental forensic chemists often do to fingerprint oil spills is look for “biomarkers”, compounds that are used are also used in petroleum exploration. They are resistant to biodegradation, and so may be good “ridges” for an oil spill fingerprint. Compounds such as hopanes and steranes, among others, are oft-monitored biomarkers. I’ve put a white box around what I believe is a biomarker elution area in the GCxGC chromatograms for a couple of tarballs from Florida.
More later, when I get my hopane and sterane standards in…
I haven’t seen my colleague Chris English this excited in quite a while, since we got tarballs from the Florida panhandle to analyze by a variety of methods, including GCxGC-FID. In fact, I thought he’d post a blog by now on this subject, but since he hasn’t, I’m stepping in!
I analyzed multiple tarballs “extracted” with carbon disulfide using GCxGC-FID with an Rxi-5ms x Rxi-17Sil MS column combination. As you can see in the contour plots below, this approach leads to easy “fingerprinting” of sample types, making the differences stand out. In fact, it may be possible to track some of these tarball samples back to the BP Deepwater Horizon Gulf oil spill of 2010, using what is called “Environmental Forensics”.
We’ll have more for you later on this subject, with Barry Burger analyzing tarballs up to C100 with a SimDist column, and Chris checking in with GC-MS data.
Quantifying FAMEs at ppm Levels in a Petroleum Diesel and Biodiesel Blend with GCxGC-FID and Rtx-200 x Rxi-17Sil MS
I promised in the previous blog on petroleum diesel:biodiesel analysis using GCxGC-FID to tell you why it’s important to determine fatty acid methyl ester (FAME) levels in some fuel blends. It’s because the US Federal Aviation Administration (FAA) has set a maximum limit of 30 ppm for FAME in aviation fuel. FAMEs can cause fuel gelling and other problems in aircraft, and may show up in petroleum fuel as a result of sharing distribution and piping systems with biofuels.
GCxGC-FID offers a way to determine FAME content accurately in the presence of bulk hydrocarbon material. The key is separating the FAMEs in the second dimension of the GCxGC chromatogram, but as noted in his paper at ISCC and an upcoming publication on his solvation parameter model [J.V. Seeley, et al., J. Chromatogr. A (2011), doi:10.1016/j.chroma.2011.07.075], John Seeley demonstrates that the first dimension column choice can have a large impact on the second dimension separation in GCxGC.
With an Rtx-200 x Rxi-17Sil MS column combination choice, the FAMEs are largely placed in the region of least interference, eluting earlier in the second dimension. On the whole, this gives better calibration curves for FAMEs in a petroleum diesel:biodiesel blend (soy biodiesel component) at the ppm level versus an Rxi-5ms x Rxi-17Sil MS setup (see table below).
You can easily see why you have a better chance of accurate FAME quantification when you look at the methyl stearate chromatograms below. These are linear chromatograms (one “slice”) for GCxGC. The methyl stearate in the 200 x 17Sil MS chromatogram elutes early, away from the bulk hydrocarbon matrix, while the methyl stearate in the 5ms x 17Sil MS chromatogram is right in the middle of the hydrocarbon mess. Mess: that’s an Okie scientific term that some people call the unresolved complex mixture.
Professor Seeley’s separations are better, and have given me something to shoot for as I continue to develop this work. Watch for more…