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Fingerprinting Crude Oils and Tarballs using Biomarkers and Comprehensive Two-Dimensional Gas Chromatography (PDF 2138kB)
...-of-flight mass spectrometry (GCxGC-TOFMS) was used to evaluate biomarker ratios in several crude oils from oil. In this study, using 43 different biomarker ratios from GCxGC-TOFMS analysis, we identified one...
High Quality Analysis of Pesticides in Marijuana Using QuEChERS, Cartridge SPE Cleanup, and GCxGC-TOFMS (PDF 672kB)
... Cleanup, and GCxGC-TOFMS By Jack Cochran, Julie Kowalski, Sharon Lupo, Michelle Misselwitz, and Amanda by GCxGC-TOFMS. Acceptable recoveries were obtained for most pesticides, and incurred pesticide residues...
Characterizing Cellular Fatty Acid Methyl Ester (FAME) Profiles to Identify Bacteria Using Gas Chromatography (PDF 340kB)
... shown here illustrate the potential of GC-TOFMS for distinguishing clinically relevant species by transesterification with sodium methanolate. Samples were then analyzed on a DANI Master GC-TOFMS equipped...
Evaluation of Dispersive and Cartridge Solid Phase Extraction (SPE) Cleanups for Multiresidue Pesticides in QuEChERS Extracts of Finished Tobacco Using GCxGC-TOFMS (PDF 4409kB)
... Pesticides in QuEChERS Extracts of Finished Tobacco Using GCxGC-TOFMS By Michelle Misselwitz, Jack Cochran . Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) was used...
Comparing Pesticide Residues in Amish and Commercially Grown Strawberries and Spinach Using QuEChERS, Various dSPE Sorbents, and GC-TOFMS (PDF 1781kB)
... Grown Strawberries and Spinach Using QuEChERS, Various dSPE Sorbents, and GC-TOFMS By Julie Kowalski , dSPE cleanup, and GC-TOFMS analysis were used to assess pesticide levels in strawberries and spinach ... pesticide residue, strawberry, spinach, sorbent, GC-TOFMS, QuEChERS, pesticide, dSPE...
Analytical Method for Polycyclic Aromatic Hydrocarbons (PAHs) in Yerba Mate Tea Using Modified QuEChERS, Solid Phase Extraction and GC-TOFMS and GC-MS/MS (PDF 634kB)
... Mate Tea Using Modified QuEChERS, Solid Phase Extraction and GC-TOFMS and GC-MS/MS By Julie Kowalski compounds and isobaric interferences was optimized on a high-phenyl stationary phase using both GC-TOFMS...
ChromaBLOGraphy: Fast GC-TOFMS of VOCs
Joeri Vercammen had a question (linear range of TOFMS) and comment (he did fast VOCs in < 4 min) for my last post, Fast GC – Another Approach. I can address both in this post using some work I did back in 2002 when cyanogen chloride was an emerging disinfection byproduct of interest for Las [...]
... a QuEChERS extraction, cSPE cleanup, and GC-TOFMS for accurate determinations of 46 pesticides for 5 minutes. The resulting final extract was then analyzed by GC-TOFMS. For cSPE cleanup , 1 m...
Large Volume Splitless Injection Using an Unmodified Split/Splitless Inlet and GC-TOFMS for Pesticides and Brominated Flame Retardants (PDF 1051kB)
.../Splitless Inlet and GC-TOFMS for Pesticides and Brominated Flame Retardants By Michelle Misselwitz and Jack Acquisition Rate: 10 spectra/sec Instrument LECO Pegasus 4D GCxGC-TOFMS Notes Carrier Gas Flow: 2...
Fingerprinting Crude Oils and Tarballs using Biomarkers and Comprehensive Two-Dimensional Gas Chromatography
...-of-flight mass spectrometry (GCxGC-TOFMS) was used to evaluate biomarker ratios in several crude oils from oil. In this study, using 43 different biomarker ratios from GCxGC-TOFMS analysis, we identified one ... Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS...
... Pegasus 4D GCxGC-TOFMS Notes See application note GNAN1338 for extraction and cleanup details. A 1.5 m of the separating power provided by GCxGC with time-of-flight mass spectrometry (TOFMS), it is easy to produce...
ChromaBLOGraphy: GCxGC-TOFMS of Riser Pipe Oil from BP Gulf Oil Spill
I recently analyzed an oil sample collected by an ROV from the riser pipe at the BP Gulf oil spill site using GCxGC-TOFMS, a powerful multidimensional technique capable of characterizing complex samples that defy one-dimensional GC-MS. The GCxGC column setup was a 30m x 0.25mm x 0.25µm Rxi-17Sil MS in the first dimension with a [...]
Evaluation of Dispersive and Cartridge Solid Phase Extraction (SPE) Cleanups for Multiresidue Pesticides in QuEChERS Extracts of Finished Tobacco Using GCxGC-TOFMS
.... Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) was used spectrometry (GCxGC-TOFMS) as the determinative technique . Analyzing tobacco using GCxGC proved ... EChERS extracts of finished tobacco products using GCxGC-TOFMS. Cleanup with dSPE tubes containing 7.5 mg of GCB...
News: Comprehensive Two-Dimensional Gas Chromatography Time of Flight Mass Spectrometry (GCxGC-TOFMS) for Environmental Forensic Investigations in Developing Countries
Author(s): Jayne de Vosa, Roger Dixonb, Gerhard Vermeulenb, Peter Gorst-Allmanc, Jack Cochrand, Egmont Rohwere, Jean-Francois Focantf a Organic and Bio-Analysis Group, Metrology in Chemistry Area, National Metrology Institute of South Africa, Private Bag X34, Lynnwood Ridge 0040, South Africa b … Continue reading
News: Achieving a Near-Theoretical Maximum in Peak Capacity Gain for the Forensic Analysis of Ignitable Liquids Using GC×GC-TOFMS
Author (s): Katie D. Nizio 1, Jack W. Cochran 2, and Shari L. Forbes 1 Centre for Forensic Science, University of Technology Sydney Restek Corporation Published By: Separations Issue: Volume 3, Issue 3 Year of Publication: 2016 Link: 10.3390/separations3030026 Abstract: At present, gas … Continue reading
Analytical Method for Polycyclic Aromatic Hydrocarbons (PAHs) in Yerba Mate Tea Using Modified QuEChERS, Solid Phase Extraction and GC-TOFMS and GC-MS/MS
... compounds and isobaric interferences was optimized on a high-phenyl stationary phase using both GC-TOFMS with hydrogen carrier gas and GC-MS/MS. Incurred values of PAHs determined via GC-TOFMS and GC-MS/MS compared ... QuEChERS extraction and solid phase extraction sample cleanup. Both GC-TOFMS and GC-MS/MS techniques...
ChromaBLOGraphy: Julie Kowalski Presents FPRW Poster on PAHS in Sugarcane Products: QuEChERS, GC-MS, GCxGC-TOFMS, Rxi-17Sil MS
Reporting again from the Florida Pesticide Residue Workshop with the news that Julie Kowalski of Restek’s Innovations group just presented the poster, “Comprehensive Screening for PAHs in Sugarcane Products after QuEChERS with Sweet Separations using an Rxi-17Sil MS GC Column, GC-MS, and GCxGC-TOFMS”. This poster represents the combined work of a great team of colleagues, [...]
News: Evaluation of Dispersive and Cartridge Solid Phase Extraction (SPE) Cleanups for Multiresidue Pesticides in QuEChERS Extracts of Finished Tobacco Using GCxGC-TOFMS
Author(s): Michelle Misselwitz, Jack Cochran, and Julie Kowalski Restek Corporation Published By: Restek Corporation Year of Publication: 2013 Link: http://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFAN1823-UNV Abstract: Tobacco is a high-value production crop for the United States and ranks 6th in the amount of pesticides applied per … Continue reading
ChromaBLOGraphy: Which GC instrument should I use for the analysis of pesticides in herbal tea? GC-MS/MS or GCxGC-TOFMS?
You may remember a while ago I posted a blog about the analysis of herbal tea using QuEChERS and GCxGC-TOFMS. The LECO Pegasus GCxGC-TOFMS is a great instrument for analyzing complex samples because of the comprehensive chromatographic separation achieved (two columns with different selectivities). The GCxGC-TOFMS also excels at non-target screening of compounds. Lucky for […]
ChromaBLOGraphy: Comprehensive Pesticide Screening Using QuEChERS, LC-MS/MS, and GCxGC-TOFMS at PittCon 2010
A recent collaboration with Applied Biosystems used a sensitive LC-MS/MS (4000 QTRAP) with a Restek Ultra Aqueous C18 column as the instrumental determination step for pesticides in QuEChERS extracts of red bell pepper, lemon, spinach, hazelnuts, raisins, and cucumber. Those same QuEChERS extracts were analyzed by a LECO Pegasus 4D GCxGC-TOFMS with Rxi-5Sil MS and [...]
My Restek colleagues Julie Kowalski, Michelle Misselwitz, and Amanda Rigdon, along with Professor Frank Dorman from The Pennsylvania State University (PSU), report here what we believe is the first QuEChERS extraction of marijuana, with subsequent analysis using GCxGC-TOFMS. We were assisted in this task by Randy Hoffman, a Police Officer Specialist/Evidence Technician at PSU, who [...]
ChromaBLOGraphy: How Dirty Are You? Part 3…Gloves…The Answers
Read The Question first… Let’s review…we soaked small pieces of different gloves in acetonitrile for 30 minutes. The samples were tested using GC-TOFMS. For relative intensity, a dashed line at the peak height of a 2 ppm PAH standard is drawn on the chromatograms. Which gloves produced the worst background? GREEN GLOVES Bright green, yellow […]
We have a very bright guy named Jaap de Zeeuw who works for Restek. Years ago he invented a system for low-pressure gas chromatography by where he used a 0.53mm GC column attached to a mass spectrometer, and a restrictor column (e.g. 0.50m x 0.10mm) press-fitted to that column and installed in a split/splitless GC [...]
Ensure Successful Polycyclic Aromatic Hydrocarbon (PAH) Analysis—Choose Specialized Rxi-PAH Columns (PDF 7240kB)
...; Acquisition Range: 45-550 amu; Spectral Acquisition Rate: 5 spectra/sec; Instrument: LECO Pegasus 4D GCxGC-TOFMS . For complete instrument conditions, visit www.restek.com and enter GC_FF1223 in the search. Red line = oven...
News: Analytical Method for Polycyclic Aromatic Hydrocarbons (PAHs) in Yerba Mate Tea Using Modified QuEChERS, Solid Phase Extraction and GC-TOFMS and GC-MS/MS
Author(s): Julie Kowalski, Amanda Rigdon, and Jack Cochran Restek Corporation Published By: Restek Corporation Year of Publication: 2015 Link: http://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFAN2086-UNV Abstract: This application note describes the development of an analytical method for PAHs in tea that allows analysts to more quickly and accurately … Continue reading
ChromaBLOGraphy: The Promise of True Peak Capacity Increase GCxGC Realized
I mentioned in my last ChromaBLOGraphy post, Phthalate-Free Personal Care Products?, that we used GCxGC-TOFMS to determine phthalates in a Las Vegas Wash water sample. While it doesn’t dive into specific compound identification, we recently published the first demonstration of a near theoretical maximum peak capacity gain for GCxGC (approximately 9x) in an open access […]
ChromaBLOGraphy: International Network of Environmental Forensics Conference – Cambridge, UK – The Invention of Mass Spectrometry and J.J. Thomson
I’m writing this post from St. John’s College at the University of Cambridge in the United Kingdom where I will be speaking at the International Network of Environmental Forensics Conference tomorrow on polychlorinated biphenyl (PCB) analysis with parallel dual-column comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (2GCxGC-TOFMS). I could wax on and on about […]
Characterizing Cellular Fatty Acid Methyl Ester (FAME) Profiles to Identify Bacteria Using Gas Chromatography
... of GC-TOFMS for distinguishing clinically relevant species and identifying low-level compounds GC-TOFMS equipped with an Rxi-17Sil MS column. This column was chosen based on its selectivity ... , presents work on the potential utility of GC-TOFMS analysis of cellular fatty acid methyl esters (FAMEs...
... is an extremely complex middle distillate product containing mainly aliphatic compounds. Using GCxGC-TOFMS, Kohl : GCxGC-TOFMS chromatogram (contour plot) of diesel analyzed with orthogonal Rxi-1ms and Rtx-FLD columns ... Comprehensive 2D GC, also known as GCxGC, is a powerful technique with a great deal of potential thousands—of components. While GCxGC is still considered emerging technology and is used primarily...
ChromaBLOGraphy: 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. [...]
High-Quality Analysis of Pesticides in Cannabis Using QuEChERS, Cartridge SPE Cleanup, and GCxGC-TOFMS
... a simple QuEChERS extraction approach with cartridge SPE (cSPE) cleanup, followed by GCxGC-TOFMS had only 1-dimensional GC been used. With GCxGC-TOFMS, cypermethrin was unequivocally identified ... challenging due to matrix complexity. The use of QuEChERS, cartridge SPE cleanup, and GCxGC-TOFMS as presented...
News: 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 Link: http://www.restek.com/Technical-Resources/Technical-Library/Petroleum-Petrochemical/petro_PCAN1789-UNV Abstract: Petroleum biomarkers are “molecular fossils” that can be analyzed with gas chromatography to fingerprint crude oil. Fingerprints … Continue reading
ChromaBLOGraphy: How Dirty Are You? Part 3…Gloves…The Question
This third installment of How Dirty Are You? is all about gloves. Outside of solvent compatibility, there is a lot of room for personal preference regarding the type of lab gloves people can use. I found 5 different gloves in our lab. The bright green gloves and yellow gloves are the two types most often […]
ChromaBLOGraphy: Gimme some sugar, baby. Analyte Protectants in Pesticide Analysis.
Scott’s post, “The Solvent Shield”, reminds me of using “analyte protectants” (APs) for determining pesticides in baby food via QuEChERS and GCxGC-TOFMS. A matrix-enhanced response occurs for many polar pesticides in food extracts, versus solvent alone, leading analysts to use “matrix-matched standards” (MMSs) for quantification (standards prepared in pesticide-free food extracts). Sugars and other hydrogen-bonding [...]
ChromaBLOGraphy: High Quality Analysis of Pesticides in Marijuana using QuEChERS, Cartridge SPE Cleanup, and GCxGC-TOFMS
Recently we reported on what we believe is the first application of QuEChERS for marijuana, using it for potency analysis with GCxGC-TOFMS. Ultimately, the plan was to determine pesticides via the QuEChERS approach, combining it with cartridge SPE cleanup as we did for dietary supplements, since sample complexity would defeat the typical dispersive SPE cleanup [...]
News: Investigating the coffee flavour in South African Pinotage wine using novel offline olfactometry and comprehensive gas chromatography with time of flight mass spectrometry
Author(s): Yvette Naudé, Egmont R. Rohwer Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa Published By: Journal of Chromatography A Issue: 1271 Year of Publication: 2013 Link: http://www.sciencedirect.com/science/article/pii/S0021967312017499 Abstract: Pinotage wine from several South African wine … Continue reading
ChromaBLOGraphy: Mining through complex data and non-target analysis is made easier with GCxGC-TOFMS
I am currently working on a project looking for pesticides in herbal tea. At this point, I am using the contents of one tea bag (~1.5g) and 10mL of freshly boiled water with a QuEChERS extraction. I am still working through the details on the impact of the hot water and what type of cleanup [...]
ChromaBLOGraphy: GCxGC is the Star at 4th Multidimensional Chromatography Workshop!
My colleagues and I made the road trip to the Ontario Ministry of the Environment in Toronto for the 4th Multidimensional Chromatography Workshop. This workshop organized by Eric Reiner at the MOE is a veritable who’s who in the world of GCxGC. I personally love going to this workshop because of the wide variety of [...]
Author(s): Michelle Misselwitz, Jack Cochran, Julie Kowalski Restek Corporation Published By: Chromatography Techniques Year of Publication: 2014 Link: http://www.chromatographytechniques.com/articles/2013/12/quechers-gc-smoke-out-tobacco-pesticides Abstract: Pesticides are used heavily on tobacco in order to increase crop production value; however, limited regulation creates the potential for high … Continue reading
ChromaBLOGraphy: GC-MS with Hydrogen Carrier Gas
At the LECO Australia Separation Science Users Group Meeting last Friday in Sydney, my colleague from South Africa, Peter Gorst-Allman, made a presentation on using hydrogen carrier gas for GC-TOFMS and GCxGC-TOFMS. His preliminary results were quite encouraging, as he noted no obvious deterioration of mass spectra quality for a wide variety of compounds, including [...]
ChromaBLOGraphy: Pesticides in Dietary Supplements
I was at the Recent Advances in Food Analysis conference in Prague last week and presented work on analyzing pesticides in dietary supplements, a very important subject given that FDA is moving to regulate these products. They are very complex herbal, botanical, etc. materials, which makes looking for trace level components very tricky. My colleagues, [...]
From October 15–19, 2012, the U.S. Environmental Protection Agency (EPA) will hold its 22nd Annual Quality Assurance Conference in Region 6, Dallas, TX. Two Restek chemists, Michelle Misselwitz and Chris Rattray, will be making the trip south to present some … Continue reading
ChromaBLOGraphy: Environmental Forensics, Water Pollution, Pansteatitis and Crocodiles dying in Kruger National Park
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 [...]
Author(s): Julie Kowalski, Michelle Misselwitz, Jason Thomas, Jack Cochran Published By: Food Safety Magazine Issue: February/March 2012 Year of Publication: 2012 Link: http://www.foodsafetymagazine.com/article.asp?id=3876&sub=sub1 Abstract: New requirements for dietary supplements to be manufactured under current Good Manufacturing Practices (cGMP) regulations have created a … Continue reading
ChromaBLOGraphy: 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 [...]
Continuing with the previous blog where I QuEChERS extracted 100ng/g PAH spikes of scallops, shrimp, and oysters, and achieved good results, I followed up with 10ng/g spikes under the same method conditions as used before (see June 28 entry). The recoveries for the 10ng/g spike are reported in the table. In general, the results are [...]
ChromaBLOGraphy: Pesticides on Roses – The QuEChERS Sample Preparation Approach
A couple of years ago we had a summer intern in our Innovations lab, Shane Stevens, whose project with us was developing a QuEChERS sample preparation approach for pesticides on cut flowers, including roses. He presented his work at the 12th Annual Environmental Chemistry Student Symposium at The Pennsylvania State University (PSU) with the distinction of [...]
Comparing Pesticide Residues in Amish and Commercially Grown Strawberries and Spinach Using QuEChERS, Various dSPE Sorbents, and GC-TOFMS
...SPE cleanup, and GC-TOFMS analysis were used to assess pesticide levels in strawberries and spinach from both -time of flight mass spectrometry (GC-TOFMS) for analyzing pesticides. Several different dispersive solid phase ... QuEChERS extraction, dSPE cleanup, and GC-TOFMS analysis were used to assess pesticide residue...
ChromaBLOGraphy: Testing for pesticides in tobacco… QuEChERS makes it easy!!
Whenever it is time to analyze pesticides in complex matrices I always hope that we can use the QuEChERS sample preparation approach and not something more laborious! The Quick-Easy-Cheap-Effective-Rugged-Safe method was developed for multiresidue pesticides in fruits and vegetables, however we have been using this approach outside of the typical fruit and vegetable matrices with [...]
Last week I had the honor to present my work at the 31st International Symposium on Halogenated Persistent Organic Pollutants (Dioxin 2011). While it is still a work in progress, Jack Cochran and I evaluated the QuEChERS extraction approach with a silica SPE cleanup for PCBs and BFRs in cow milk and human breast milk. [...]
Herbal tea, a non-caffeinated drink made from plants, herbs, or spices has been used throughout history for its potential medicinal benefit. Various herbal material is mixed depending on the desired medicinal or flavor properties for the tea. As with any plant based commodity, there is the potential for pesticide residues to remain in the final […]
ChromaBLOGraphy: US Drug Enforcement Administration Exerts Federal Control Over Synthetic Marijuana Compounds (JWH-type; CP-47,497; and Cannabicyclohexanol)
I heard on the news the other day that the DEA is taking action to control synthetic marijuana compounds such as JWH-018, JWH-073, and JWH-200, in addition to a couple others. It hasn’t been that long ago that herbal “incenses” that provide a pot-like high when smoked popped up for sale on the internet, and [...]
ChromaBLOGraphy: Phthalate-Free Personal Care Products?
In her recent ChromaBLOGraphy posts, Minimizing Phthalate Interferences Using the Rtx-CLPesticides/Rtx-CLPesticides2 Columns and EPA Regulated Phthalates FREE?, my colleague Dan Li pointed out the ubiquitous nature of phthalates in our world because of their widespread use in plastic consumer products, and that phthalates likely have adverse human health effects, including as endocrine disruptors. Any of […]
ChromaBLOGraphy: This isn’t your average CSI, the International Network of Environmental Forensics (INEF)
Next week (June 10-12) at the Pennsylvania State University (PSU) the International Network of Environmental Forensics conference is being held. This isn’t your typical crime scene investigation but, 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.” We [...]
Previous posts on this subject noted good spike recoveries for PAHs at the 10 and 100 ng/g level from seafood, including scallops, shrimp, and oysters. The beauty of QuEChERS is its multiresidue extraction capability, so it was no trouble to report data for PCBs and organochlorine pesticides, in addition to the previously determined PAHs. That’s [...]
ChromaBLOGraphy: Spring is finally here! Unfortunately so are the ticks…
After a long and cold winter here at the Restek headquarters in Bellefonte, PA, USA it seems that spring is finally here! It is so nice this time of year to get outside and enjoy the weather and the beautiful outdoors that Pennsylvania has to offer. Unfortunately after a hike in the woods there is […]
ChromaBLOGraphy: Wildfires in the Western United States: The smoke can be as dangerous as the flames, especially for firefighters.
The drought continues and wildfires are raging across the Western United States. In Washington State alone, the wildfires have burned over 1400 square miles (that’s 3600 km2). Brave men and women from across the United States are coming to the aid and trying to contain these historical fires. Unfortunately lives of the firefighters are in […]
ChromaBLOGraphy: Restek at the 40th International Symposium on Capillary Chromatography and 13th GCxGC Symposium
Restek is proud to have numerous presentations in the orals scientific program for the 4oth ISCC and 13th GCxGC Symposium, which will take place in Riva del Garda, Italy in May. Exploding a Peak Capacity Increase Record by Using Hydrogen Carrier Gas for Comprehensive Two-Dimensional Gas Chromatography – Time-of-Flight Mass Spectrometry (Jack Cochran, Julie Kowalski, Christopher […]
News: Determination of Emerging Contaminants in Wastewater Utilizing Comprehensive Two-Dimensional Gas-Chromatography Coupled with Time-of-Flight Mass Spectrometry
Author(s): Sarah Prebihalo1, Adrienne Brockman1, Jack Cochran1,2, Frank L. Dorman1,3 1. Pennsylvania State University, Forensic Science Program 2. Restek Corporation 3. Pennsylvania State University, Department of Biochemistry and Molecular Biology Published By: Journal of Chromatography A Year of Publication: 2015 … Continue reading
ChromaBLOGraphy: NACRW 2013: Fun (and Science) in the Sun!
Last week was the 50th Annual Florida Pesticide Residue Workshop…now officially named the North American Chemical Residue Workshop. The conference was held at a beautiful beach resort, but don’t be fooled though there was plenty of science. The program was jammed packed with presentations, panel discussions, forums, posters and exhibits. Topics ranged from pesticide [...]
ChromaBLOGraphy: No Prescription Needed: Pharmaceuticals in Your Supplements
There are many fake products out there including foods like “virgin” olive oil, honey and branded liquor. I hear a lot about these because my work focuses on food and food safety. Food fraud seems to be on the rise…at the very least governments and researchers are devoting more resources to finding and tracking incidents. [...]
Last week at the 8th GCxGC Symposium, in conjunction with the 35th International Symposium on Capillary Chromatography, Don Patterson, Jr. was awarded the inaugural GCxGC Scientific Award. This award was cosponsored by Restek and LECO. Don retired from the Centers for Disease Control and Prevention (CDC) after an illustrious career specializing in human exposure assessment [...]
ChromaBLOGraphy: QuEChERS Workshops in South Africa
One of the best things about working at Restek is their commitment to continuing education for chromatographers, both inside and outside of their doors. This takes many forms, including the seminars produced by Rick Parmely, our Training Director, and through other efforts like the QuEChERS workshops I’m currently doing in South Africa. In the last [...]
The AOAC annual meeting is fast approaching. Beginning this Sunday, September 30th and running through next Wednesday, October 3rd, the 2012 AOAC meeting in Las Vegas, Nevada promises to be another exciting conference. The final program has been announced and … Continue reading
ChromaBLOGraphy: Fast GC – Another Approach
Jaap de Zeeuw and I are often discussing fast GC, including low-pressure (or vacuum-outlet) GC and smaller inside diameter columns (such as 0.10 or 0.15mm). I dug out some work I’d done in 2005 with a 0.18mm x 0.18µm Rxi-5ms column, but I cut the column down to 4m to REALLY go fast for some [...]
ChromaBLOGraphy: QuEChERS Extraction of Oil Contaminated Seafood – PAHs
“Growing up” as an environmental analytical chemist, I always think of hydrophobic contaminants, like Polycyclic Aromatic Hydrocarbons (or PAHs), needing hydrophobic solvents to isolate/extract them from hydrophobic matrices, like fish or seafood. (Dang, he’s using hydrophobic so much he must be rabid…) In fact, I’d seen reduced recoveries when trying to QuEChERS extract (with polar [...]
ChromaBLOGraphy: Restek Gooseneck Splitless Liner with Semivolatiles Wool versus Vendor A MS Certified Liner for Pesticides by GC
We chemists are a funny lot. We want GC-MS systems that will detect fg levels, so we spend tons of money on high resolution MS or MS/MS to get there and then we ignore the GC injector liner, a part that costs 10,000 times less than some instruments. But as my colleagues Scott Grossman and [...]
Large Volume Splitless Injection Using an Unmodified Split/Splitless Inlet and GC-TOFMS for Pesticides and Brominated Flame Retardants
...-LVSI GC-TOFMS (n = 3). 1 µg of a 4 L sample volume, concentration step, and 12.5 µL injection volume on a GC with a sensitive TOFMS ... Concurrent solvent recondensation large volume splitless injection (CSR-LVSI) GC/MS is used here...
ChromaBLOGraphy: Modifying QuEChERS for complicated matrices- Dry Samples
Before getting in to this discussion, I recommend reading my previous blog post first regarding classical applications for methods based on Quechers. https://blog.restek.com/quechers-dspe-selection-which-one-is-best/ QuEChERS methods were originally written to analyze pesticides in fruit and vegetable matrices, most of which have high water content and low fat content. More recently, the technique has been used for […]
ChromaBLOGraphy: Shoot-and-Dilute GC – A Way to Keep GC Systems Up Longer to Help Lower Cost of Analyses
Dilute-and-shoot LC-MS/MS is a selective and sensitive technique often used in determining pesticides in foods. Because of competitive ionization effects seen with electrospray (ESI) and atmospheric pressure chemical ionization (APCI) methods, quantitative accuracy suffers for trace compounds of interest when matrix coelutions occur. Dilution of extracts (or sometimes raw samples) is a good way of […]
As in years past, Restek sent a contingent of environmental and air chromatography experts to the National Environmental Monitoring Conference (NEMC). This year’s event took place in Washington, DC, and featured talks from our own Michelle Misselwitz, Jason Herrington, and … Continue reading
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