7.5-Min Screening Analysis of Multiresidue Pesticides in Brown Rice Flour

Published By: Restek Corporation

Year of Publication: 2018

Link: http://www.restek.com/Technical-Resources/Technical-Library/Foods-Flavors-Fragrances/fff_FFSS2930-UNV

Abstract: Multiresidue pesticides analysis presents many challenges, from extensive lists of chemically diverse analytes to the negative effects of complex matrix components. The optimized chromatographic method described here allows the analysis of hundreds of compounds in as little as 7.5 minutes with a total cycle time under 10 minutes, ensuring fast, accurate sample screening and increased lab productivity.

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering: QuEChERS

Authors: Alexandria M. Pavkovich, David S. Bell

Restek Corporation

Published By: ScienceDirect

Year of Publication:  June 2018

Link: https://www.sciencedirect.com/science/article/pii/B9780124095472139721#!

Abstract: QuEChERS has become a widely accepted and highly adaptable method for pesticide residue analysis. The analytical scope and applicability of QuEChERS are expanding at a rapid pace. Numerous research groups work with QuEChERS for analysis of pesticides, veterinary drugs, mycotoxins, environmental and natural contaminants, drugs of abuse, and a number of other areas of interest.

The term QuEChERS is an acronym for Quick, Easy, Cheap, Effective, Rugged, and Safe. QuEChERS is a quick and relatively easy extraction method that uses low solvent volumes and a user-friendly collection vessel while providing acceptable and reproducible analyte recovery for a wide range of pesticides and target analytes. QuEChERS allows for the extraction of homogenized matrices by using salt formulations to drive the separation of the organic extraction solvent and water.

Q-sep Extraction Salts Make QuEChERS Even Easier

For years, the QuEChERS approach has made sample preparation faster and easier than traditional methods. Now, the new Q-sep extraction salts from Restek make an easy technique even simpler. Restek’s new, improved design provides the salts in a more granular form, so they flow freely and are easier to pour than powders. The convenient slim packets are easy to open and fit perfectly into extraction tubes, ensuring complete transfer without any spills. These new extraction salts offer the same technical performance you’ve come to expect from the Q-sep line of QuEChERS products, just redesigned for your convenience. Keep your workflow running smoothly with new Q-sep extraction salts from Restek!


Restek to Offer May 3 Twitter Q&A Session on QuEChERS

#AskRestekOn Tuesday, May 3, Restek will host the next installment of the popular #AskRestek question-and-answer (Q&A) series on Twitter. This free, hour-long chat forum with Restek chromatography experts will start at 3:00 p.m. Eastern Time (12:00 noon Pacific Time) and will focus on QuEChERS sample preparation. Whether Restek customers or not, analysts are encouraged to follow the chat and join in with their own questions.

Panelists will include:

Mike Chang (@MC_Restek), Restek’s Product Marketing Manager (PMM) for Sample Preparation

Jonathan “Munch” Keim (@MunchAtRestek), Restek’s Education Coordinator as well as former Technical Service Manager and Sample Preparation PMM..

To stay informed leading up to the chat, follow @Restek, @MC_Restek, and @MunchAtRestek on Twitter.

At 3:00 p.m. EST (12:00 noon PST), on Tuesday, May 3, follow along by simply visiting https://twitter.com/hashtag/AskRestek and clicking All Tweets (app) or Live (browser). Periodically refresh your browser or Twitter feed to catch the latest posts.

People interested in receiving a reminder to join the chat can e-mail crm@restek.com. Restek will send a reminder on the day of the event to those who sign up.

To join in the conversation, simply tweet a question or comment on Twitter and be sure to include the #AskRestek hashtag in your post.

For additional help using Twitter, you can also go to https://support.twitter.com/categories/281#

#AskRestek is your direct line to Restek’s chromatography experts on Twitter. Follow Restek on Twitter now for this event and more valuable chromatography information: www.twitter.com/restek

Attend Restek’s Vendor Seminar on GC-MS/MS Performance at RAFA 2015

In addition to exhibiting, Restek will hold a vendor seminar at the 7th International Symposium on Recent Advances in Food Analysis (RAFA). Presented by Restek’s own Julie Kowalski on November 5 at 1:30 p.m., this valuable seminar will explore prolonging GC-MS/MS performance by means of Shoot-and-Dilute injection versus analyte protectants. Prizes will also be given away to select attendees.

RAFA 2015 takes place on November 3–6, 2015 at the Clarion Congress Hotel Prague, Czech Republic. This biennial symposium summarizes the latest strategies and identifies current issues surrounding food quality and safety control analysis and bioanalysis. While at RAFA, be sure to also stop by Booth# 46 for a visit and to discuss our latest innovations in food science.

Visit http://www.rafa2015.eu/programme_vendors_seminars.html today to register for the symposium and to sign up for Restek’s vendor seminar.

Prolonging GC-MS/MS Performance: Shoot-and-Dilute Injection versus Analyte Protectants

Thursday, November 5, 1:30 p.m.
Julie Kowalski and Jack Cochran
Restek Corporation

For more information, e-mail  julie.kowalski@restek.com

In gas chromatography–mass spectrometry (GC-MS), most problems occur on the front end, at the GC inlet, where compounds can degrade during hot splitless injection, active compounds can be irreversibly adsorbed to inlet liner surfaces, and nonvolatile material from dirty samples can compromise the transfer of less volatile compounds of interest from the inlet to the GC column. These issues are magnified due to the very slow inlet flow during splitless injection, which is typically less than 2 mL/min.

Two strategies to mitigate these issues will be demonstrated in this seminar. One approach is to use split injection, what we call, and “Shoot-and-Dilute.” With newer, more sensitive GC-MS/MS systems, LOD and LOQ requirements are often achievable using split injections at ratios of 10:1 or greater. Increased flow through the inlet during split injection minimizes residence time inside the inlet liner, which decreases compound degradation and adsorption, and maintains acceptable data quality longer. In addition, GC oven start temperature can be higher, thus reducing overall run time as well as the time needed to re-equilibrate the GC oven prior to the next analysis. Another benefit of split injection is improved peak shape for early eluting pesticides when injecting acetonitrile-based QuEChERS extracts.

The second strategy to overcome GC inlet problems is to use “analyte protectants,” which are essentially volatile and chromatograph-able masking agents such as sugars, diols, etc., that are co-injected with each sample and standard to temporarily occupy active sites in the GC inlet liner and column. These analyte protectants have low m/z ions and the mass spectrometer can essentially overlook them in favor of target compounds.

Both strategies were tested with multiclass pesticides and compared against a typical splitless injection method without use of analyte protectants for QuEChERS samples. For Shoot-and-Dilute, viability of split injection based on detectability of a wide range of analytes was determined. Optimized split injection, inlet, and initial GC oven temperatures were determined. Benefits of analyte protectants were evaluated by peak shapes and responses of both well-behaved and problem pesticides. The goal of both Shoot-and-Dilute and analyte protectants approaches is to improve initial and long-term chromatographic performance.

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.

QuEChERS: The Concept

Author(s): Julie Kowalski, Amanda Rigdon, and Jack Cochran
Restek Corporation

Published By: Separation Science

Issue: vol. 5, issue 8

Year of Publication: 2013

Link: For the full print issue, visit http://www.sepscience.com/docs/Bespoke/Editions/SepSci/Sepsci0813eu.pdf?utm_source=iContact&utm_medium=email&utm_campaign=eLearning%20Newsletter%20-%20Europe%20Sep%20Sci&utm_content=

Abstract: The original QuEChERS sample preparation methods were designed for pesticide residue analysis of high water-content foods, specifically fruits and vegetables. QuEChERS methods provide “just enough” sample preparation because highly selective and sensitive modern instrumentation does not require extremely clean samples. In the first two installments of this series (#1 and #2), official methods were reviewed, as well as considerations for method development. Adjustments to the original methods for some difficult commodities and pesticides were reviewed as well. This article will focus on QuEChERS metamorphosis into a concept. “QuEChERS” will be used as a broad term in this article to describe not only modified QuEChERS methods but also methods based on QuEChERS principles. The success of QuEChERS relates back to the attributes set forth by the originators; Quick, Easy, Cheap, Effective, Rugged and Safe. In addition to these benefits, great flexibility and quick method development have encouraged the expansion of QuEChERS from specific methods to generic techniques, and now to a sample preparation concept.

QuEChERS: Beyond the Basics

Author(s): Julie Kowalski and Jack Cochran
Restek Corporation 

Published By: Separation Science

Issue: vol. 5, issue 4

Year of Publication: 2013

Link: http://www2.sepscience.com/Techniques/Sample-Prep/Articles/1863-/QuEChERS-Beyond-the-Basics

For the full print issue, visit http://www.sepscience.com/docs/Bespoke/Editions/SepSci/Sepsci0413eu.pdf?utm_source=iContact&utm_medium=email&utm_campaign=eLearning%20Newsletter%20-%20Europe%20Sep%20Sci&utm_content=

Abstract: QuEChERS is a sample preparation approach that was designed to be easy, cheap but effective and rugged at the same time. It is most often used for pesticide residue analysis but its beneficial features have assisted it in branching to other fields such as environment, bioanalytical and clinical. QuEChERS was originally designed for fruits and vegetables and proven to work especially well for high water content fruits and vegetables (>80 %) with slightly acid pH (5–6). However, there are commodities that don’t fit into this food type. Adjustments to the typical QuEChERS procedures extend its usage outside of these typical or easy commodities. Common examples include very acidic food like citrus fruits and fatty foods like avocado, milk and oils.

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


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
For more information, e-mail michelle.misselwitz@restek.com

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
For more information, e-mail michelle.misselwitz@restek.com

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, e-mail chris.rattray@restek.com

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.

QuEChERS: A Primer

Author(s): Julie Kowalski and Jack Cochran
Restek Corporation

Published By: Separation Science

Issue: vol. 4, issue 12

Year of Publication: 2012

Link: http://www.sepscience.com/Techniques/Sample-Prep/Articles/865-/QuEChERS-A-Primer

For the full print issue, visit http://www.sepscience.com/docs/Bespoke/Editions/SepSci/Sepsci1012eu.pdf?utm_source=iContact&utm_medium=email&utm_campaign=eLearning%20Newsletter%20-%20Europe%20Sep%20Sci&utm_content=

Abstract: Quick, Easy, Cheap, Effective, Rugged and Safe, the QuEChERS (pronounced “catchers”) method is based on work done and published in 2003 by Anastassiades et al. QuEChERS was developed as an extraction method for pesticides in fruits and vegetables, coupled with a cleanup method that removes sugars, lipids, organic acids, sterols, proteins, pigments, and excess water. QuEChERS involves two simple steps: first, a homogenized sample is extracted and partitioned using an acetonitrile and salt solution, then, the supernatant is cleaned using a dispersive solid-phase extraction (dSPE) technique. This QuEChERS approach offers a user-friendly alternative to traditional liquid-liquid and solid-phase extractions.