AOAC 133rd Annual Meeting - Final Program

Poster Abstracts | Wednesday

WEDNESDAY, SEPTEMBER 11, 2019 Poster Presentation Viewing: 10:00am–5:00pm Author Presentations: 12:00pm–1:00pm ANALYSIS OF FOODBORNE CONTAMINANTS AND RESIDUES P-W-001 Douglas Hayward , U.S. Food and Drug Administration, College Park, MD, USA Novel Approaches for Removing Lipids Before the Isotope Dilution Mass Spectrometry Measurement of Persistent of Organic Pollutants (POPs) in Dairy Foods All POPs methods for animal derived foods utilize mixtures of nonpolar and polar organic solvents for the extraction of 10-100 g of dairy, eggs or fish. Such extractions dissolve associated test portion lipids completely. These methods must eliminate all co-extracted lipids (>99.99%) before determination by isotope dilution GC-MS where the sample volume must be 10-20 µL. Validated approaches require high quantities of sulfuric acid or GPC with additional high quantities of organic solvent. In this work, two novel approaches are described to remove co-ex- tractant lipids using either an isolation column with the adsorbent order reversed (from EPA 1613) or acetonitrile extraction where 90% of the potential co-extractants are not dissolved. These two new procedures require a restriction of the test portion intake to <4 g of crude lipid, although less sulfuric acid and organic solvent is required. These approaches also require use of 13 C 12 uniformly labelled standards for each target analyte with sufficient recovered signal and a sufficient steady state between standards and the test portion to provide accurate results. Using either two approaches gave comparable results in cream or butter when compared to the conventional approach. Presenter: Douglas Hayward, U.S. Food and Drug Administration, College Park, MD, USA, Email: douglas.hayward@fda.hhs.gov P-W-002 Titan Fan , Jingping Xie , Beacon Analytical Systems, Inc., Saco, ME, USA Development of ELISA Assays for the Detection of Industrial Dyes in Food One of the major food adulteration and safety issues is the treating of industrial dyes as food coloring additives. Rhodamine B (RB) is consided to be potentially both genotoxic and carcino- genic and Methyl Yellow (MY) is the azo dyes family with known carcinogenic properties. A competitive immunoassay was devel- oped for the quantitative determination of RB in sauce samples. Rabbit polyclonal antibodies against RB were produced and the limit of detection in the sample was 1 ppb with the range from 1 to 10 ppb. Total assay time of this quick test was 15 min. Soy sauce, fish sauce, red enchilada sauce, and marinated Teriyaki sauce purchased from U.S. supermarkets were extracted with acetonitrile. RB was spiked in 5 sauces with 1 and 5 ppb and the recoveries were 71-117%. The second competitive immuno- assay was developed for the quantitative determination of MY. Rabbit polyclonal antibodies against MY were produced and

the assay calibrators’ range from 0.5 to 50 ppb. Total assay time of MY was 30 min. A 1 ppb MY was spiked in soy sauce and red enchilada sauce and the recoveries were 94-100%. Higher concentration of spiked samples will be investigated further. Presenter: Jingping Xie, Beacon Analytical Systems, Inc., Saco, ME, USA, Email: jingping@beaconkits.com P-W-003 Terri Christison , Jeffrey Rohrer , Thermo Fisher Scientific, Sunnyvale, CA, USA Direct Determination of Paraquat, Diquat, and Related Cationic Polar Pesticides in Homogenized Food Samples Using Ion Chromatography and High-Resolution Accurate Mass Spectrometry Robust, sensitive analytical methods are needed to determine six polar pesticides (paraquat, diquat, chloromequat, mepiquat, trimethylsulfonium, and morpholine) due to their chronic and acute toxicity. Here we demonstrate direct determinations of six cationic polar pesticides in food samples using cation-exchange chromatography with serial detection by suppressed conductivity and high-resolution accurate mass spectrometry (HRAM MS) in full scan and Parallel Reaction Monitoring (PRM) modes for targeted MS/MS. The pesticides were separated using an electrolytically generated acid gradient from 1 to 40 mM at 0.4 mL/min and 40 ºC. After passing through a desalting electrolytic suppressor, the pesticides were detected by suppressed conductivity and ionized by positive ESI-MS and acetonitrilefor detection by MS. The method was applied to extracted, diluted homogenized food samples following the Quick Polar Pesticide (QuPPe) method. The polar pesticides had good peak shape with good peak asymmetries and eluted from the column within 20 min. Diquat- paraquat with the carbon isotopic masses within 2 m/z fully coeluted but were easily resolved in PRM mode by HRAM MS. The six pesticides had good accurate mass, between <2 to 2.5 ppm m/z normalized to the true isotopic mass. Good accuracy was found, 80-120% recoveries of spiked in reagents. Sensitivities were single digit µg/L LODs. Presenter: Terri Christison, Thermo Fisher Scientific, Sunnyvale, CA, USA, Email: terri.christison@thermofisher.com P-W-004 Manali Aggrawal , Terri Christison , Jeffrey Rohrer , Thermo Fisher Scientific, Sunnyvale, CA, USA Selective and Sensitive Determination of Bromate in Bread by IC-MS Potassium bromate is a food additive used as “flour improver” in the baking industry. Bromate is considered a carcinogenic and nephrotoxic substance. Due to its carcinogenic potential, many countries have banned this use of potassium bromate. The U.S. FDA restricts its use and allows up to 50 mg of potassium bromate to 1 kg of flour, with the belief that the baking process converts potassium bromate to non-carcinogenic bromide. However, if baking is incomplete, there may be significant residual bromate. It is thus important to monitor bromate concen- tration in finished flour products. We developed a method for a selective and sensitive determination of bromate in flour that uses ion chromatography coupled with single quadrupole mass

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