Restek at AOAC 2024
23-28 August, Baltimore, MD, U.S.
Visit the AOAC 2024 website
Learn More About Featured Restek Products
- Inert LC Columns
- PFAS Solutions
- QuEChERS
- dSPE tubes
- EZLC Method Translator and Chromatogram Modeler
- LPGC Columns
- Resprep SPE Cartridges
Questions about these presentations? Contact Restek Technical Service.
ORAL PRESENTATIONS:
Collaborative Study Examines the Contribution of Reference Standards to “Potency Inflation"
Monday, August 26, 4:05-4:25 p.m.
Dan DeLurio1 (presenter), Joe Konschnik1, Kate Calati2, Nandakumara Sarma3, Jeff Rawson4
1. Restek Corporation; 2. Cayman Chemical; 3. U.S. Pharmacopeia (USP); 4. Institute of Cannabis Science (ICS)
Abstract
Certified Reference Materials (CRMs) are the analytical foundation for safety and quality data for the wide variety of cannabis products sold throughout the world today. Cannabis industry experts are observing inconsistencies between labeled and measured concentrations of cannabinoids, commonly referred to as “potency inflation.” These variations stand to challenge the credibility of an industry still striving to gain consumer trust and relevance to stakeholders. While there can be many sources within the analytical laboratory for these variations, some have surmised that inconsistencies among CRMs are responsible.
The Cannabis Working Group (CWG) of American Council of Independent Laboratories (ACIL) undertook a collaborative volunteer research study to determine the variability and comparability of cannabinoid CRMs for use in calibrating instruments for cannabis testing. The overarching goal of this research study was to determine, among five accredited independent testing laboratories, the variance of THC and THCA containing CRM products from five reference standard manufacturers.
This presentation will focus on displaying observed variability of CRM production lots and manufacturers among a variety of acidic and decarboxylated THC CRMs. The five labs evaluated a total of 21 unique reference standard products, including both single and multi-component mixes. Study design, logistics and results will be presented by the authors along with conclusions regarding the observed variability among CRMs examined.
Simultaneous Determination of Alternaria Toxins, Ergot Alkaloid Epimers, and Other Major Mycotoxins in Various Food Matrices by LC-MS/MS
Wednesday, August 28, 3:00-4:30 p.m.
Diego A. Lopez, (presenter), Shun-Hsin Liang, Justin Steimling
Restek Corporation
Abstract
Food commodities are vulnerable to different types of fungal pathogens and could be contaminated with differential classes of mycotoxins. It is ideal to implement a generic method for simultaneous determination of multi-mycotoxins in different food matrices or agricultural products.
In this study, a simplified sample preparation procedure and a reliable LC-MS/MS analytical method were developed for comprehensive measurement of 37 regulated and emerging mycotoxins, including 5 Alternaria toxins, 6 major ergot alkaloids, and their corresponding epimers. Four different food matrices (baby wheat cereal, peanut, tomato puree, and blended flour) were chosen for method validation to demonstrate the applicability of this analytical method to a wide range of food types.
Chromatographic analysis was performed using MS-friendly acidic mobile phases and completed with a short 11-minute cycling time for proper separation of ergot alkaloid epimers. The recoveries of all mycotoxins (except citrinin) in fortified samples were from 70% to 120%, and the relative standard deviation was less than 20%.
The established workflow was simple and fast for multi-mycotoxin determination with a unique benefit of simultaneous analysis of Alternaria toxins and ergot alkaloids. Furthermore, a novel inert Biphenyl LC column demonstrated the high degree of Non-Specific Binding (NSB) that occurs between the column’s stainless-steel hardware and certain mycotoxins. The implementation of the inert column offers a robust and improved chromatographic performance as it mitigates the NSB for highly adsorptive analytes (e.g. fumonisins, aflatoxins, and tenuazonic acid) leading to better sensitivity and peak shapes without the need of mobile phase additives or sample passivation.
POSTER PRESENTATIONS:
Reduced Instrument Downtime for Organochlorine Pesticide Analysis by Using an Optimized SPE Cartridge for Sample Extract Cleanup
Monday, August 26, 12:00-1:00 p.m.
Colton Myers, (presenter), Jason Thomas, Alexis Shelow
Restek Corporation
Abstract
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 provided, 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 instrumental performance and sample path inertness.
In this presentation, a cartridge is introduced that is designed specifically to be utilized exactly like the frequently employed Florisil cartridge, but to a much superior effect for highly pigmented and inlet degrading samples. What this means for the analyst is the ability to consistently generate calibration curves that can be maintained longer and reduced instrument maintenance, ultimately leading to higher sample throughput.
Comparison of Analytical Methods for the Quantification of PFAS in Food Contact Material
Tuesday, August 27, 12:00-1:00 p.m.
Joe Konschnik1 (presenter), Milica Jovanovic2, Erich Leitner1
1. Restek Corporation; 2. Graz University of Technology, Institute of Analytical Chemistry and Food Chemistry
Abstract
Per- and polyfluoroalkyl substances (PFAS) analysis has become crucial due to their omnipresence from plentiful sources, their persistence, and their potential health risks. Accurate determination of the sources and potential exposure from PFAS would require available standards for all produced PFAS as well as their precursors and degradation products.
Additionally, for many substances there is no information about their structure, partially due to many precursors and unknown intermediate products, and partially because they are patented by the companies that produce them.
As of today, numerous techniques have been either developed or modified for the analysis of PFAS, but these methods exhibit significant variations in their capacity to provide specific information.
We analyzed paper material consisting of fresh fiber and secondary materials intended to produce food packaging for the presence of PFAS. The samples were extracted and analyzed for 23 different PFAS substances using the targeted approach with LC tandem mass spectrometry (LC-MS/MS). This analytical technique detects specific, easily ionizable PFAS with high sensitivity. However, one drawback of this approach is that it allows the identification of less than 1% of the PFAS known today. For this reason, we used combustion ion chromatography (CIC) to determine the content of extractable organic fluorine compounds (EOF) and compare it to the total fluorine content.
The Analysis of PFAS in Milk by LC-MS/MS
Tuesday, August 27, 12:00-1:00 p.m.
Diego A. Lopez, (presenter), Jamie York
Restek Corporation
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a class of manufactured organic compounds that are used for a wide array of applications and products. The environmental prevalence and bioaccumulation of these compounds can lead to contamination of produce and other commodities meant for human consumption. In this application, a workflow was developed for the analysis of 28 PFAS compounds in milk that resolves the target PFAS from potential bile acid interferences that share the same mass transition. To prepare samples, a QuEChERS approach coupled with dSPE was implemented. This workflow returned exceptional results for the four PFAS compounds required in the Guidance Document on Analytical Parameters for the Determination of Per- and Polyfluoroalkyl Substances (PFAS) in Food and Feed released by the European Union Reference Laboratory for Halogenated POPs in Feed and Food. Recoveries for the four main PFAS compounds ranged from 100.7–113.0% and %RSD of 2.56–16.6% with acceptable method accuracy and precision results achieved for the majority of other compounds also monitored. While detectable levels of bile acid interferences were not observed in tested milk samples, the chromatographic method developed herein is suitable to apply to other matrix samples of animal origin for the detection of PFAS compounds where high levels of bile acids may be present.
Method Development of Cannabinoids for LC-UV Analysis Using a Virtual Method Development Tool
Tuesday, August 27, 12:00-1:00 p.m.
Dan DeLurio1 (presenter), Melinda Urich1, Justin Steimling1, Chris Nelson1, Tim Yosca1, John Garrett2
1. Restek Corporation, 2. Analytical Innovations LLC
Abstract
Traditional method development of cannabinoid separations can be time-consuming and costly, but emerging cannabinoids often require reoptimization of current methods. This development and optimization require several steps, including method scouting, development, and optimization. To reduce cost and save time, a no-cost tool was used to perform virtual method development. Compounds were selected from a database containing over 40 cannabinoids. Methods were developed to instantly model separations by adjusting parameters such as instrument/system effects (dwell and extra column volume); temperature; flow rate; and mobile phase additives. In this work, methods were developed virtually, then transferred to an HPLC-UV, and retention times from the experimental vs. modeled chromatograms were compared. To determine if results from the modeler were acceptable, retention times should not exceed more than ±15 seconds or no more than 10% of the run time. Results show this virtual tool can be used to develop cannabinoid separations quickly and accurately. This virtual tool can aide in the optimization of existing methods for the addition of new cannabinoids, offer an on-demand consultative user experience, and lead to greener solutions for method development.
Exploration of New Low-Pressure GC Columns for Food and Environment Emerging Contaminants
Tuesday, August 27, 12:00-1:00 p.m.
Jessi Collier (presenter), Jana Hepner, Whitney Dudek-Salisbury, Chris English
Restek Corporation
Abstract
The Low-Pressure GC (LPGC technique) has been successfully used in the past for pesticide residues’ analysis. However, the technique is very versatile, and it allows for other applications, especially if different column phases are used. So far, the majority of the applications have been using the “5”-type phase (95% dimethylpolysiloxane, 5% diphenyl polymer). To expand on the previous applications, four additional column phases were selected (cyanopropylphenyl dimethylpolysiloxane; 50% dimethylsiloxane, 50% diphenyl; 65% dimethylsiloxane, 35% diphenyl; and trifluoropropylmethyl polysiloxane phases) to analyze various food and environmental contaminants, such as nitrosamines, alkylfurans, phthalates, arylamines and fluorotelomer alcohols. The LPGC techniques provided significant reduction in run times (up to 3.3x faster runs) and helium consumption reduction (up to 81% less helium used), while keeping an acceptable resolution.
Mitigating Matrix Issues via Filter Aid to Improve Solid-Phase Extraction Methods
Tuesday, August 27, 12:00-1:00 p.m.
Colton Myers (presenter), Jason Hoisington, Alexis Shelow
Restek Corporation
Abstract
Solid phase extraction (SPE) stands as a valuable sample preparation technique for water samples, utilized in the extraction of substances such as PFAS and semi-volatiles from drinking water. Despite its efficacy, SPE encounters challenges in non-drinking water matrices where solid particles can obstruct SPE cartridges, prolonging extraction or necessitating multiple cartridges per sample. EPA Method 1633 recently introduced glass wool to address this issue; however, manually adding wool can be laborious and inconsistent. This presentation introduces an integrated filter aid for SPE cartridges, enhancing consistency compared to glass wool. Incorporating the filter aid mitigates matrix-related clogging, leading to expedited extraction, reduced cartridge consumption, and more reliable analytical outcomes.