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

Link: www.sciencedirect.com/science/article/pii/S0021967315014132

Abstract: An analytical method for identification of emerging contaminants of concern, such as pesticides and organohalogens has been developed and utilized for true discovery-based analysis. In order to achieve the level of sensitivity and selectivity necessary for detecting compounds in complex samples, comprehensive gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS) was utilized to analyze wastewater samples obtained from the Pennsylvania State University wastewater treatment facility (WWTF). Determination of emerging contaminants through a process of combining samples which represent “normal background” and comparing this to new samples was developed. Results show the presence of halogenated benzotriazoles in wastewater samples as well as soil samples from Pennsylvania State University agricultural fields. The trace levels of chlorinated benzotriazoles observed in the monitoring wells present on the property indicate likely environmental degradation of the chlorinated benzotriazoles. Preliminary investigation of environmental fate of the substituted benzotriazoles indicates their likely degradation into phenol; an Environmental Protection Agency (USEPA) priority pollutant.

QuEChERS, GC Smoke Out Tobacco Pesticides

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 levels of pesticide residues to remain on finished tobacco products. Analysis of pesticides on tobacco is extremely challenging due the natural complexity of this botanical matrix. The work detailed here used the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) approach for extraction and GCxGC-TOFMS for analysis. In addition, the experimental design compared dispersive solid phase extraction (dSPE) and cartridge solid phase extraction (cSPE) cleanup approaches. The wide range of pesticides chosen for this study covered many of the 37 pesticides that have been approved by the U.S. EPA for use on tobacco. The combination of QuEChERS, GCxGC-TOFMS, and dispersive solid phase extraction cleanup allowed easy and accurate analysis and separation of target pesticide residues from the tobacco matrix.

Applying Comprehensive Analysis to EPA Method 1613B Samples: Discover Those Compounds Usually Discounted in Environmental Samples

Author(s): Jayne de Vos1, Jack Cochran2, Eric J. Reiner3, Peter Gorst-Allman4
1. National Metrology Institute of South Africa, 2. Restek Corporation, 3. Ontario Ministry of the Environment, 4. LECO Africa

Published By: Current Trends in Mass Spectrometry

Issue: July 2013

Year of Publication: 2013

Link: www.spectroscopyonline.com/spectroscopy/article/articleDetail.jsp?id=817655

Abstract: Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are ubiquitous environmental pollutants that are persistent and toxic. The historical quantitative analysis of these compounds has been achieved with high-resolution targeted analysis using magnetic sector instruments, with subsequent lower resolution analysis to identify other contaminants. Advances in technology have led to comprehensive time-of-flight (TOF) mass spectrometers that can quantify PCDDs or PCDFs while simultaneously acquiring data on other contaminants in the samples. Samples that had been analyzed using EPA Method 1613B conditions on a sector instrument were analyzed with a high performance TOF mass spectrometer and a low-resolution comprehensive two-dimensional gas chromatography (GC×GC) TOF instrument. The quantitative results from the sector, the high-resolution TOF, and the GC×GC-TOF systems are compared in this article.

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 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.

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 cellars has been produced with a novel coffee flavour. We have investigated this innovative coffee effect using in house developed solventless sampling and fractionating olfactometric techniques, which are unique in their ability to study synergistic aroma effects as opposed to traditional gas chromatography olfactometry (GC-O) which is designed to, ideally, evaluate single eluting compounds in a chromatographic sequence. Sections of the chromatogram, multiple or single peaks, were recaptured on multichannel open tubular silicone rubber (polydimethylsiloxane (PDMS)) traps at the end of a GC column. The recaptured fractions were released in a controlled manner for offline olfactory evaluation, and for qualitative analysis using comprehensive gas chromatography coupled to time of flight mass spectrometry (GC×GC–TOFMS) for compound separation and identification, thus permitting correlation of odour with specific compounds. A combination of furfural and 2-furanmethanol was responsible for a roast coffee bean-like odour in coffee style Pinotage wines. This coffee perception is the result of a synergistic effect in which no individual compound was responsible for the characteristic aroma.

 Acknowledgment(s):We wish to thank Gerhard Overbeek for assisting in the extraction of wine and aroma evaluation, Phakama Botha for assistance in wine extraction, Dr Fanie van der Walt for the custom-built olfactometer, David Masemula for the assembly of multichannel PDMS traps, Dr Peter Gorst-Allman from LECO Africa (Pty) Ltd. for use of a LECO Pegasus 4D GC×GC–TOFMS, Philip Langenhoven from LECO Africa (Pty) Ltd. for sponsorship, Jack Cochran from Restek for kind donation of GC columns and consumables, SASOL and the National Research Foundation (NRF) for financial support.

Misselwitz and Rattray to Speak at the EPA’s 22nd Annual Quality Assurance Conference

Chris Rattray

Chris Rattray

Michelle Misselwitz

Michelle Misselwitz

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 of their latest work, including GCxGC analysis of pesticides and pharmaceutical and personal care products (PPCPs) as well as lowering detection limits for drinking water methods using large volume splitless injection (LVSI). For more details on each presentation, see below.

This free conference has been organized for years by the incredibly dedicated Charles Ritchie and is a great way to network with a wide range of colleagues and get caught up to speed on recent developments in environmental analysis. You can learn more about the Quality Assurance Conference on the EPA’s website (www.epa.gov/earth1r6/qa/index12.htm) and can also re-read Michelle Misselwitz’s blog on last year’s event (blog.restek.com/?p=3916) .

We hope to see you there!

 

Technical Presentations

TUESDAY, OCTOBER 16, 2012

9:30 a.m. / Session E
The QuEChERS Sample Preparation Approach and Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry for the Analysis of Pesticides in Tobacco

Michelle Misselwitz

Tobacco is a high-value production crop for the United States and ranks 6th among the amount of pesticides applied per acre in American agriculture. Even after the processing of tobacco, some pesticide residues remain on the final product. We used the Quick–Easy–Cheap–Effective–Rugged–Safe (QuEChERS) sample preparation approach to isolate pesticide residues from loose cigarette tobacco. Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) was used to determine pesticide residues in the resulting extracts.

3:00 p.m. / Session C
Analysis of Pharmaceutical and Personal Care Products and Other Emerging Environmental Contaminants in Water Using a Highly Efficient GCxGC-TOFMS System

Michelle Misselwitz

Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) is a powerful multidimensional approach to sample analysis that is unmatched by traditional one-dimensional chromatography. By operating the system to maximize efficiency in both the first and second dimension, GCxGC-TOFMS has the ability to detect, identify, and quantify or semi-quantify an unlimited number of target, non-target, and unknown compounds (including emerging compounds of concern) with full mass spectra and sub- to low-pg sensitivity. Using this technique, water samples were collected from the urban river in Las Vegas to analyze a large number of pharmaceutical and personal care products and other emerging environmental contaminants.

4:00 p.m. / Session D
Achieving Lower Detection Limits for Multiple Drinking Water Methods Using Large Volume Splitless Injections on an Unmodified Split/Splitless Injection Port

Chris Rattray
For more information, email Chris Rattray.

Utilizing a large volume splitless injection is advantageous for many reasons. Some of these include shipping and extracting significantly smaller sample sizes, reducing extract concentration, or decreasing limits of detection for trace-level analysis in drinking water. The drawback for many is that large volume injections typically require a specialized injection port. However, with concurrent solvent recondensation-large volume splitless injection (CSR-LVSI), a large volume injection can be achieved on an unmodified Agilent split/splitless injection port. Here we analyzed multiple drinking water methods using CSR-LVSI on an Agilent 7890/5975C GC-MSD and injected up to 10 µL to achieve lower detection limits.

A Comprehensive Approach to Pesticide Residue Testing, Including Non-Target Analysis, for Fruits, Vegetables, and Nuts, Using QuEChERS, LC-MS/MS, and GCxGC-TOFMS

Author(s): Jack Cochran1, Julie Kowalski1, Jason Thomas1, Michelle Misselwitz1, Rebecca Wittrig2*, Andre Schreiber3

1Restek Corporation, 110 Benner Circle, Bellefonte, Pennsylvania 16823, USA
2AB SCIEX, 353 Hatch Drive, Foster City, California 94404, USA
3AB SCIEX Research and Development, 71 Four Valley Drive, Concord, Ontario, Canada L4K 4V8
*Current address: Restek Corporation, 110 Benner Circle, Bellefonte, Pennsylvania 16823, USA

Published By: Restek Corporation

Year of Publication: 2012

Link: http://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFAN1566-UNV

Abstract: Food commodities were fortified with pesticides and processed using the QuEChERS sample preparation technique. Samples were analyzed by both GCxGC-TOFMS and LC-MS/MS. The foods chosen varied in water, fat, and pigment content, so the ruggedness of QuEChERS as well as the performance of GCxGC-TOFMS and LC-MS/MS could be assessed. Commodities tested were red bell pepper, cucumber, black seedless grape, spinach, lemon, raisin, and hazelnut. Recovery values were determined by matrix-matched standards for the GC method and by solvent standards for the LC method. Evaluation of GCxGC-TOFMS and LC-MS/MS, along with the QuEChERS approach itself, was made by comparison of recovery values and incurred pesticide concentrations.

Good recoveries were obtained for most pesticides in most commodities as determined by GCxGC-TOFMS and LC-MS/MS. Sometimes GCxGC-TOFMS did not have the selectivity necessary for determining certain pesticides in the most complex samples. In this regard, dispersive SPE (dSPE) cleanup was ineffective at removing significant matrix interferences in lemon, raisin, and hazelnut extracts for some target pesticides. Corrupted LC-MS/MS quantification for some pesticides was observed, especially in lemon and hazelnut extracts, and likely resulted from ion suppression or was due to quantification by solvent-only standards. Incurred pesticide quantifications were comparable for GCxGC-TOFMS and LC-MS/MS. GCxGC-TOFMS was able to identify non-target pesticides.