Krone Advances to Intel ISEF and State Science Fair

Liesl Krone presents her award-winning research.

Liesl Krone presents her award-winning research.

Restek is pleased to congratulate Liesl Krone, a student at Crossland Ninth Grade Center in Granbury Texas, whose science fair project recently advanced to the ExxonMobil State Science and Engineering Fair (EMTSEF) after placing 1st at the Fort Worth Regional Science and Engineering Fair. Her project entitled “Stay Home or Go Global—Local Versus Imported Fruit” also won an honorable mention for Best in Show during regional competition, garnering her an invitation to present her work at the Intel® International Science and Engineering Fair® (Intel ISEF).

Since food safety standards and the use of pesticides differ around the world, Liesl was curious to know whether locally grown fruits would be freer of pesticides than their imported counterparts. To find out, Liesl paired a QuEChERS sample extraction and cleanup procedure with LC-MS/MS analysis and evaluated pesticide residue levels across a wide range of samples that included organic and non-organic, as well as locally grown and imported berries and pome fruits.

After analyzing 13 samples for approximately 180 compounds, Liesl found that pesticide levels were low overall and that the presence of pesticides did not correspond to country of origin. Interestingly, the sample that contained the most pesticides was an organic pear from the U.S. This led her to conclude that organic labeling does not always guarantee a fruit is truly organic or free of pesticides. As Liesl puts it, “The issue seems to be whether a fruit is truly organic, and it doesn’t matter so much that the fruit is imported.”

This project was made possible by Analytical Food Labs, AB SCIEX, and Restek Corporation.

Congratulations, Liesl, and good luck at Intel ISEF and the state competition!


New Raptor™ ARC-18 Columns Are Born for LC-MS/MS

The birth of Restek’s new Raptor™ SPP LC column line began with the innovative Biphenyl phase, and it has now grown to include a new Restek® phase: the ARC-18.

Raptor™ LC ColumnsRaptor™ ARC-18 ColumnDesigned and intended specifically for use on LC-MS/MS systems, the Raptor™ ARC-18 column offers a well-balanced retention profile without the drawbacks of using an ordinary C18 in the harsh, acidic mobile phases needed for mass spectrometry (MS). Even after extended use in these low-pH (≤ 2.0) conditions, the sterically protected ARC-18 offers consistent retention, peak shape, and response for charged bases, neutral acids, small polar compounds, and more. For the rapid analysis of large, multiclass assays by LC-MS/MS, the Raptor™ ARC-18 truly is ahead of the curve.


About Raptor™ SPP LC Columns: Superficially porous particles (commonly referred to as SPP or “core-shell” particles) changed the world of LC by dramatically boosting column efficiency and reducing analysis times, but they were only the beginning. With Raptor™ LC columns, Restek chemists have combined the speed of SPP with the resolution of highly selective USLC® technology. This new species of chromatographic column allows you to more easily achieve peak separation and faster analysis times without expensive UHPLC instrumentation. Raptor™ LC columns provide the practicing analyst with the most powerful tools available for fast, efficient method development and increased sample throughput. And because they are from Restek, Raptor™ LC columns are backed by manufacturing and quality systems you trust along with internationally renowned Plus 1 service.

Our 2014 Seminar Schedule is Now Live — Register today!

Visit to view our 2014 U.S. seminar schedule and register today. We hope to see you during our travels!

Restek Learning Network

About the Restek® Learning Network: Well-trained chromatographers make productive analysts — and the widely acclaimed Restek® Learning Network (RLN) offers training solutions to fit every level of expertise, budget, schedule, and analytical topic. The RLN provides a variety of educational and networking opportunities to help you reduce guesswork, improve throughput and reliability, and raise your confidence in generated data.

QuEChERS, GC Smoke Out Tobacco Pesticides

Author(s): Michelle Misselwitz, Jack Cochran, Julie Kowalski
Restek Corporation

Published By: Chromatography Techniques

Year of Publication: 2014


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.