NACRW 2019

56th North American Chemical Residue Workshop

56th North American Chemical Residue Workshop
56th North American Chemical Residue Workshop


O-29 / 3:15–3:35 p.m. / Room: Orchid Ballroom
Session 9: Emerging Topics in Trace Level Analysis
Title: The Need for Safety and Authenticity Testing Methods for Natural Colors
Joe Konschnik1, Mark Goldschmidt2, Doug Williams3
1. Restek Corporation, 2. Sensient Technologies, 3. Kalsec, Inc.
For more information, email Joe Konschnik.
Read abstract

Color additives are applied in a broad range of products that impact our lives. With up to 85% of consumers’ buying decisions potentially influenced by color, appropriate application of color is critical to product selection and experience. From a quality and safety perspective, for colors from natural sources, there is a general lack of product definitions or publicly available purity, quality, and safety specifications that are consistently applied. Under current regulations, color additives fall into two categories: Those subject to the FDA’s certification process and those that are exempt. Recently, a growing consumer interest in “natural colors” has led to a broad application of plant extracts and other materials as “exempt” colorants in foods and beverages. A significant risk of adulteration of natural colors exists, ranging from simple misbranding or misuse of the term “natural” on a product label to potentially serious cases of physical, chemical, and/or microbial contamination from raw material sources, improper processing methods, or intentional postproduction adulteration. Consistent industry‐wide safety standards are needed to address the manufacturing, processing, application, and international trade of colors from natural sources to ensure quality and safety throughout the supply chain. Methods are needed for the analysis of residual solvents, microorganisms, heavy metals, pesticides, and mycotoxins as a means to establish such standards. The focus of this presentation is to highlight the expanding use of natural colors in the food industry and discuss key potential safety hazards affecting sourcing and use of food colorants from natural sources.


Quantitation of Mycotoxins in Four Food Matrices Comparing Stable Isotope Dilution Assay (SIDA) with Matrix Matched Calibration Methods by LC-MS/MS
Joe Konschnik (presenter), Dan Li, Justin Steimling, Ty Kahler
Restek Corporation
For more information, email Joe Konschnik.
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Mycotoxins are secondary fungal metabolites produced by mold that may be found in food or feed. They can cause severe health problems in humans and animals and can result in significant economic losses. Among the hundreds of toxic mycotoxins, aflatoxins, fumonisins, deoxynivalenol, ochratoxin A, HT-2 toxin, zearalenone, and T-2 toxin are considered as a major concern for corn, wheat, peanuts, and other agricultural products. LC-MS has become the standard and is now widely used for routine mycotoxin analysis and identification. One of the challenges faced by LC-MS techniques is the matrix effects caused by the use of electrospray ionization (ESI). Generally, sample preparation, chromatographic, and calibration techniques are the common strategies for reducing the negative effects of matrix effects. Standard addition, matrix matching, and stable isotope dilution assay (SIDA) are all possible calibration solutions. In this work, a quick “dilute-filter-shoot” method was used for sample preparation. A seven-minute LC-MS/MS method using a Biphenyl-phase column was developed and verified for quantifying twelve mycotoxins in four commodities: corn, peanut butter, brown rice, and corn and wheat mixed. Both SIDA and matrix-matched calibration methods were applied, compared, and evaluated in terms of recovery, efficiency, advantages, and limitations.

Optimizing a 190+ Pesticides Multiresidue Screening Workflow for the Preparation and Analysis of Produce by LC-MS/MS
Landon A. Wiest1 (presenter), Alexandria Pavkovich Bush1, Jamie York2, Dan Li1, and Joe Konschnik1
1. Restek Corporation, 2. The University of Texas at Arlington
For more information, email Landon Wiest.
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Pesticides are ubiquitously used to help increase crop yields; however, they can pose risks for public health and pollinators (honeybees). Faster multiresidue screening workflows, which combine easier sample preparation techniques that yield higher recoveries with lower instrument detection limits in fruits and vegetables, are often sought. Accomplishing these goals increases sample throughput and reduces costs for laboratories and their clients. To demonstrate the feasibility of developing improved methods, organic celery and other representative matrices were spiked with pesticides down to 10 ppb. Samples were extracted using Restek QuEChERS slim pouch salts and cleaned up with complementary dSPE. Each sample was diluted 10x with water prior to analysis. Separations were performed with a Restek Raptor ARC-18 column (100 mm x 2.1 mm, 2.7 µm) on a Shimadzu Nexera UHPLC. A Shimadzu LCMS-8060 was used for detection. Recovery and precision results from organic celery, spinach, and other samples will be shown.

The Detection of Fipronil and Fipronil Sulfone in Eggs
Jamie York1, Landon A. Wiest2 (presenter), Justin Steimling2, Ty Kahler2, and Kevin A. Schug1
1. The University of Texas at Arlington, 2. Restek Corporation
For more information, email Landon Wiest.
Read abstract

Fipronil is a pesticide in the phenylpyrazole class and is used for a wide array of products, including some home flea and tick preventatives/treatments for household pets. The use of fipronil near animals for human consumption or laying hens is not permitted in Europe, as fipronil is fat soluble and could contaminate meat and chicken eggs. However, millions of eggs were destroyed last year due to illegal use of fipronil in Europe near laying hens, which resulted in the contamination of millions of eggs with the insecticide. Fipronil and its metabolite of similar toxicity, fipronil sulfone, inhibit the action of GABA in the central nervous system. Fipronil is more effective at blocking the GABA action in insects than in mammals, but fipronil sulfone is less selective. Once ingested fipronil can cause hypertension, paralysis, and death in insects and can cause indigestion, sweating, nausea, dizziness, agitation, vomiting, and seizures in humans. Because of the illegal use of fipronil around laying hens, it is crucial to develop a rapid, reliable, and sensitive method for detection of fipronil and its metabolite in eggs. In this study, we optimized methods for extraction of fipronil from eggs using QuEChERS. We also evaluated multiple HPLC stationary phases and developed an optimized method calibrated from 0.1 to 10 ppb.

Optimizing GC-MS Analysis of 3-MCPD and Glycidyl Esters
Jana Rousova, Joe Konschnik, Hansjoerg Majer, Alexandria Pavkovich Bush (presenter), and Chris English
Restek Corporation
For more information, email Alexandria Pavkovich.
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3-MCPD and glycidyl esters in edible oils are contaminants that are formed through refining processes, and several of these substances have been classified as possible human carcinogens. Methods, which are similar to one another, have been developed by ISO, AOCS, and DGF for analyzing these contaminants. While the methods cover extraction and derivatization techniques in detail, very little attention is paid to the GC-MS methods. With emerging automated systems, it is important to simplify and speed up the method by optimizing the parameters, to include switching to split injection.

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