NEMC 2019

National Environmental Monitoring Conference

Restek at NEMC 2019
Restek at NEMC 2019


Extended List of PFAS Analysis
Shun-Hsin Liang, Mike Chang
Restek Corporation
For more information, email Mike Chang.
Download a PDF of the full presentation.


Using Method Translation to Increase Throughput While Maintaining the Same Elution Profile
Chris Rattray
Restek Corporation
For more information, email Chris Rattray.
Download a PDF of the full presentation.
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Existing methods can be accurately scaled down to smaller, high-efficiency, narrow-bore columns using Restek’s EZGC method translator. With a scaled-down column, a properly translated method, and a GC Accelerator kit (when necessary), you can obtain the same chromatographic separation—often with greater sensitivity—in a fraction of the time without making a capital investment. Real world examples will be given for semivolatiles, pesticides, and petro applications.

Reducing Instrument Downtime for Organochlorine Pesticide Sample Analysis Using an Optimized Graphitized Carbon Black Cartridge for Extract Cleanup
Jason Thomas
Restek Corporation
For more information, email Jason Thomas.
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Some of the most commonly encountered problems experienced by those analyzing environmental samples for organochlorine pesticides are instrument downtime and shortened calibration periods, both due to the deleterious effects of coextracted matrix components that are introduced into the analytical instrument during sample injection. In addition to this, chromatographic interferences complicating identification and quantification have also made life difficult for environmental analysts. Although there are cleanup options, such as Florisil, silica gel, and alumina, these normal phase solutions often do not adequately remove the less polar and high molecular weight compounds that are responsible for diminishing instrument performance and sample path inertness.

In this presentation, a cartridge is introduced that is designed specifically to be used exactly like popular Florisil cartridges, but to a much superior effect for highly pigmented and inlet degrading samples. What this means for the analyst is calibration curves that can be maintained longer and reduced instrument maintenance, ultimately leading to higher sample throughput.


Complete Fractionation of Extractable Petroleum Hydrocarbons Using Newly Developed Small Bed EPH SPE Cartridges
Mike Wittrig
Restek Corporation
For more information, email Mike Wittrig.
Download a PDF of the full presentation.
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Due to its prominent use in the modern era, petroleum, in one form or another, is a ubiquitous commodity. From its primary use as an energy source to its role as an essential feedstock for industry, petroleum’s widespread use leads to instances of uncontrolled releases into the environment.

When an assessment of the affected soil or waters from a spill is required, an effective and comprehensive analytical method should be utilized to make an appropriate decision about the remediation required to mitigate the hazardous nature of the contaminated areas. One such method is the Method for Determination of Extractable Petroleum Hydrocarbons (EPH), contributed by the Massachusetts Department of Environmental Protection. Recognizing the utility of this method, other states, such as New Jersey and Texas, followed the lead and adopted their own versions based largely upon this work.

The ability to successfully execute such a method requires an SPE cartridge that can discern between two major classes of compounds and depends upon the cartridge’s ability to completely fractionate the sample extract for subsequent GC analysis. This ability relies on the properties of the silica, as well as on the moisture levels in the finished cartridge. The SPE cartridge must also provide a background free of interferences, which depends on the cleanliness and lack of leachable materials in the silica and the cartridge components.

This work explores the capabilities of Restek’s small bed SPE EPH cartridges to effectively perform EPH analytical methods.

Analysis of Ultrashort-Chain (C2, C3) and Alternative PFAS: LC-MS/MS Method Development and Application to Water Samples
Shun-Hsin Liang
Restek Corporation
For more information, email Shun-Hsin Liang.
Download a PDF of the full presentation.
Read abstract

LC-MS/MS methods for the analysis of legacy short chain (C4, C5) and long chain (>C5) per- and polyfluoroalkyl substances (PFAS) using reversed-phase (RP) chromatography have been well-established. For low-level PFAS analysis, it is necessary to use a delay column to isolate the interferences generated by HPLC systems, especially when direct injection methodology is adopted without a sample concentration procedure. With proper modification, typical RP methods can be applied to the analysis of emerging PFAS alternatives, such as GenX and ADONA, which are perfluoroalkyl ether carboxylic acids (PFECAs) used as PFOA substitutes. These established LC methods, however, may not be suitable for the analysis of newly trending ultra-short chain (C2, C3) PFAS, mainly due to insufficient retention of these compounds on typical RP columns.

While the use of short chain PFAS (PFBA and PFBS) is intentional, numerous studies have shown the ubiquitous occurrence of C2 and C3 ultra-short chain PFAS in aqueous environmental samples. These include trifluoroacetic acid (TFA), perfluoropropanoic acid (PFPrA), perfluoroethane sulfonate (PFEtS), and perfluoropropane sulfonate (PFPrS). It was shown that PFPrA is the predominant PFAS (up to 45% of total detectable PFAS) in rain and snow samples collected from the U.S., France, and Japan. To date, not many studies have identified the contamination sources and levels of these ultra-short chain PFAS. A recent study detected PFEtS and PFPrS in aqueous film-forming foams (AFFFs) and ground waters from 11 military sites in the U.S., indicating AFFF firefighting foam may be one of the sources of the ultra-short chain PFAS contamination.

This presentation will discuss LC-MS/MS method development for ultra-short chain C2 and C3 PFAS analysis and analytical methodologies for simultaneous chromatographic determination of alternative and legacy PFAS.

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