Restek’s new and improved EZGC chromatogram modeler is just as simple to use as the original software, but it now offers advanced options for selecting phases, changing carrier gases and control parameters, further optimizing results, and much more. The software has been updated based on user feedback, allowing chromatographers to develop and optimize GC methods more efficiently and effectively than ever before.
The new Pro EZGC chromatogram modeler allows you to do the following:
• Start with either the column you have or a column recommended by the program.
• Select compounds from Restek’s libraries or bring your own list.
• Target specific compounds for resolution.
• Alter the GC conditions to optimize your model quickly and easily.
• Repeatedly refine the temperature program.
• Switch carrier gases.
• Change the control method.
• View elution temperatures in the peak list.
• See results for multiple phases.
This free, online software provides a customized, interactive model chromatogram that matches real-world chromatograms with exceptional accuracy. Users can zoom in, view chemical structures, and even overlay the mass spectra of coeluting compounds. The updated Pro EZGC chromatogram modeler is an easy, risk-free way to increase lab productivity through faster, more effective method development and optimization.
Author: Jack Cochran
Published By: LCGC Chromatography Online
Issue: Volume 12, Issue 16
Year of Publication: 2016
Hopefully, by now at least, readers who are following this Practical GC series on split injection gas chromatography (GC) (1–3) have been able to take advantage of its benefits in their own laboratories. Chemists analyzing environmental samples, especially those that produce dirty extracts, could have the most to gain from split injection GC given the wide variety of semivolatile organic compounds that are typically determined. Analyte lists include compounds that can react with GC inlet liner surfaces during splitless injection, leading to degradation of those compounds, which prohibits their accurate quantification. In fact, an example was given in my first Practical GC article in The Column (1) for the pesticides endrin and DDT. Sample extracts containing high concentrations of involatile material exacerbate the situation because the nonvolatiles are deposited on the inlet liner wool and bottom seal where they catalyze degradation of sensitive compounds. Buildup of nonvolatile material in the inlet during repeated splitless injections leads to even higher breakdown. Split injection mitigates the degradation potential because the typical inlet flow is 10 times (or more) higher than for splitless injection. The time for unwanted reactions on liner surfaces, including those that have been modified by nonvolatile coextractives, is reduced in split injection.
Author(s): Terry Reid and Carrie Sprout
Published By: Restek Corporation
Year of Publication: 2016
Link: original article retired March 13, 2019; replaced with: https://www.restek.com/Technical-Resources/Technical-Library/General-Interest/general_GNSS2975-UNV
Abstract: Restek offers a wide selection of LC guard columns and choosing the right one is a simple task when you base your decision on your analytical column. By selecting the right guard column system (holder, cartridge, and/or filters) you can provide dependable protection and ensure optimal performance from your analytical column for many analyses to come.
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
At present, gas chromatography–quadrupole mass spectrometry (GC-qMS) is considered the gold standard amongst analytical techniques for fire debris analysis in forensic laboratories worldwide, specifically for the detection and classification of ignitable liquids. Due to the highly complex and unpredictable nature of fire debris, traditional one-dimensional GC-qMS often produces chromatograms that display an unresolved complex mixture containing only trace levels of the ignitable liquid among numerous background pyrolysis products that interfere with pattern recognition necessary to verify the presence and identification of the ignitable liquid. To combat these challenges, this study presents a method optimized to achieve a near-theoretical maximum in peak capacity gain using comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS) for the forensic analysis of petroleum-based ignitable liquids. An overall peak capacity gain of ~9.3 was achieved, which is only ~17% below the system’s theoretical maximum of ~11.2. In addition, through the preservation of efficient separation in the first dimension and optimal stationary phase selection in the second dimension, the presented method demonstrated improved resolution, enhanced sensitivity, increased peak detectability and structured chromatograms well-suited for the rapid classification of ignitable liquids. As a result, the method generated extremely detailed fingerprints of petroleum-based ignitable liquids including gasoline, kerosene, mineral spirits and diesel fuel. The resultant data was also shown to be amenable to chromatographic alignment and multivariate statistical analysis for future evaluation of chemometric models for the rapid, objective and automated classification of ignitable liquids in fire debris extracts.