Ghost Peaks in Gas Chromatography Part 3: Sample Contamination and Ghost Peaks Formed by The Stationary Phase Itself

Author(s): Jaap de Zeeuw
Restek Corporation

Published By: Separation Science

Issue: vol. 5, issue 7

Year of Publication: 2013


For the full print issue, visit

Abstract: In the last issue we discussed possible sources for ghost peaks related to the carrier gas and the gas lines. The injection port septa, O-rings can also be a source for ghost peaks. Here we look at the sample itself and the different “contaminations” that can result in unwanted “extra” peaks. Also the stationary phase in the column can play an interesting role in ghost-peak formation.

Whole Air Canister Sampling Coupled with Preconcentration GC/MS Analysis of Part-per-Trillion Levels of Trimethylsilanol in Semiconductor Cleanroom Air

Author(s): Jason S. Herrington
Restek Corporation

Published By: Analytical Chemistry

Issue: 85 (16)

Year of Publication: 2013


Abstract: The costly damage airborne trimethylsilanol (TMS) exacts on optics 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]). In this study I developed a whole air canister-based approach for field sampling trimethylsilanol in air, as well as a preconcentration gas chromatography/mass spectrometry laboratory method for analysis. The results demonstrate clean canister blanks (0.06 pptv [0.24 ng/m3], which is below the detection limit), excellent linearity (a calibration relative response factor relative standard deviation [RSD] of 9.8%) over a wide dynamic mass range (1–100 pptv), recovery/accuracy of 93%, a low selected ion monitoring method detection limit 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. Samples collected at two silicon wafer fabrication facilities ranged from 10.0 to 9120 pptv TMS and appear to be associated with the use of hexamethyldisilazane priming agent. This method will enable semiconductor cleanroom managers to monitor and control for trace levels of trimethylsilanol.

Comprehensive Two-Dimensional Gas Chromatography With a Multi-Capillary Second Dimension: A New Column-Set Format for Simultaneous Optimum Linear Velocity Operation

Author(s): Daniela Peroni1, Andjoe A.S. Sampat1, Wil van Egmond2, Sjaak de Koning3, Jack Cochran4, Roy Lautamo4, Hans-Gerd Janssen1,5

1. University of Amsterdam, 2. NLISIS, 3. LECO Corporation, 4. Restek Corporation, 5. Advanced Measurement and Data Modelling, Unilever

Published By: Journal of Chromatography A

Issue: tbd

Year of Publication: 2013


Abstract: Comprehensive two-dimensional gas chromatography (GCxGC) suffers from the impossibility to operate both dimensions at their optimum carrier gas velocity at the same time due to the different inner diameters of the columns typically employed. The use of multiple parallel capillary columns in the second dimension (GC x multi-GC) is studied as a means to achieve simultaneous optimum-velocity operation. A programme written in Microsoft Excel® was developed to calculate the efficiency of the two dimensions in GC x multi-GC for different numbers of columns in the second dimension. With the aid of this programme the appropriate number of columns was selected. Columns with maximum repeatability were specifically manufactured to grand suitable performance, i.e. to avoid band broadening effects caused by inter-column variations. 1D-GC experiments were carried out on the columns separately and combined in parallel. The performance of the parallel column set was consistent with that of the individual columns, with over 9100 plates generated (approximately 10,000 plates/m). A GC x multi-GC set-up was successfully installed. Model experiments proved the possibility to operate both dimensions at their optimum linear velocity simultaneously. The suitability of the novel second dimension column format to perform multidimensional separations was also shown for a number of selected applications.

Our NACRW 2013 Presentations Are Now Online

Did you have the chance to take in any of our technical posters or enjoy the Restek vendor seminar at NACRW 2013? There was so much to do — so much it was simply impossible to see everything — so we wanted to let you know that we’ve posted our presentations on our NACRW website:   Review them at your leisure, and feel free to get in touch with the authors directly to discuss them further.

Restek would also like to take this opportunity to congratulate our own Dr. Julie Kowalski for being elected as the 2015 NACRW president! She has been an active member of the organizing committee for the Florida Pesticide Residue Workshop (FPRW)—now known as the North American Chemical Residue Workshop (NACRW)—and was instrumental in setting up the meeting’s first-ever social event: the Dali Museum visit. Having just finished its 50th year, NACRW has earned wide acclaim in the industry, and we look forward to seeing Julie at its helm in 2015.

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


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.

Almost $4,000 Raised for Tornado Relief by Restek Customers and Employee-Owners

Restek_logo72_hexIn the aftermath of the rare and deadly EF5 tornado that ripped through Oklahoma in May, Restek felt compelled once again to try to help ease the suffering of those affected by devastation. As was done after Superstorm Sandy and other disasters, Restek modified our Wizard Dollars program to give customers the option of donating to this noble cause. For two months, interested customers could click a box during checkout asking that the Wizard Dollars they earned on their chromatography purchases be converted into cash to aid those in need—and Restek employee-owners also pitched in. After the one-for-one corporate match, a total of $3,940 was sent to the Red Cross on behalf of Restek and our customers. We would like to thank our customers for their generosity and caring.