AOAC 133rd Annual Meeting - Final Program

Poster Abstracts | Wednesday

spectrometry (IC-MS). Six commercial flour and flour products including homemade bread baked using flour containing potas- sium bromate, were analyzed. Flour samples were extracted with high-purity water and subjected to a series of simple clean up steps before they were analyzed on the IC-MS system. A recently introduced high-capacity anion-exchange column was used to separate bromate from matrix anions. The method showed good precision with RSDs <0.2%, and <5% (n=8), for retention time and peak area respectively. Bromate recoveries from flour samples ranged from 86-110%. The limits of detec- tion and quantitation of bromate in the prepared solution were 0.10 and 0.34 µg/L, respectively, which corresponded to 5 and 17 µg/kg in bread. Presenter: Terri Christison, Thermo Fisher Scientific, Sunnyvale, CA, USA, Email: terri.christison@thermofisher.com P-W-005 Beibei Huang , Terri Christison , Jeffrey Rohrer , Thermo Fisher Scientific, Sunnyvale, CA, USA Determination of Polar Pesticides in Grapes Using a Compact Ion Chromatography System Coupled with Tandem Mass Spectrometry Polar pesticides in food and beverages have become a hot topic in recent years. Two well-known representatives of this group are the broad-spectrum systematic herbicide glyphosate and its metabolite AMPA. Pesticides are used in vineyards world- wide, and this can lead to pesticide residues on grapes and in the final wine product. Other foods and beverages may also contain pesticide residues. This has led to much contro- versy as reported in the media and scrutiny from governing bodies such as the World Health Organization (WHO) and the European Food Safety Authority (EFSA), due to the potential adverse health effects of pesticides. There is increased demand to test for these compounds. Analyzing polar pesticides is challenging, as they can have low recovery when using liquid/ liquid partition methods based on QuEChERS, and poor retention in reversed-phase liquid chromatography. Ion chro- matography (IC) is a technique designed for polar analytes and provides excellent chromatographic resolution in a wide range of samples. Combining IC with the power of a highly selective and sensitive mass spectrometer (MS) has led to the development of an IC-MS/MS method for the direct analy- sis of 16 pesticides and related compounds. Using grapes as the sample, this method was developed with a run time of 20 minutes and detection limits below those required to meet EU maximum residue limits (MRL). Presenter: Terri Christison, Thermo Fisher Scientific, Sunnyvale, CA, USA, Email: terri.christison@thermofisher.com P-W-006 Dimple Shah , Waters Corp., Milford, MA, USA Developing a Robust LC-MS/MS Method for the Determination of Anionic Polar Pesticides in a Range of Foodstuffs Without Derivatization Glyphosate continues to cause controversy and so analysis is of considerable interest to governments, the food industry and contract testing laboratories. Many wish to move away from

methodology that employs derivatization to save time and expand the scope to cover other polar and ionic pesticides. Chromatographic retention and separation was optimized using a novel HILIC column, applying an acidified mobile phase gradi- ent, with and without ammonium formate. The performance of a buffered and un-buffered version of the method was compared. Removal of the ammonium formate from the mobile phase resulted in improved sensitivity without compromising chromato- graphic performance. The aim was to achieve chromatographic retention and baseline separation of isobaric compounds whilst providing maximum sensitivity of all target analytes. Foods of plant origin were prepared using a modified version of the QuPPe extraction procedure and spiked with a panel of representative anionic polar pesticides. All analytes were sufficiently retained detected at concentrations <0.01 mg/kg in matrix-matched standards using the new acidified method. The performance of the LC-MS/MS method was assessed using the relevant criteria defined in the SANTE guidance document. Linearity was assessed through matrix-matched calibration. Ion ratios and retention times agreed well with reference values and all were within the required tolerances. The details of a new improved method will be presented. Presenter: Dimple Shah, Waters Corp., Milford, MA, USA, Email: dimple_shah@waters.com P-W-007 Yingchen Li , Qilei Guo , Thermo Fisher Scientific, Beijing, China; Alexander Semyonov , Thermo Fisher Scientific, Austin, TX, USA; Ed George , Thermo Fisher Scientific, San José, CA, USA; Fausto Pigozzo , Thermo Fisher Scientific, Milan, Italy; Deepali Mohindra , Thermo Fisher Scientific, Sunnyvale, CA, USA Analysis of Thirteen Major Polar Anionic Pesticides by a New Single IC-MS/MS Method A new integrated «sample-to-results» workflow for the reli- able and sensitive quantitation of polar anionic pesticides and contaminants in food. The workflow is based on the use of high capacity ion exchange columns with post column eluent suppression coupled to a high sensitivity triple quadrupole mass spectrometer (IC-MS/MS). Polar anionic pesticides and contaminants such as chlorate, perchlorate, glufosinate, N-acetyl glufosinate, 3-MPPA, glyphosate, AMPA, N-acetyl AMPA, fose- tyl-Al, phosphonic acid, ethephon, HEPA, often occur as residues in food; but are not always included in food safety monitoring programs, because they are not “amenable” to more conven- tional generic multi-analyte methods. The developed IC-MS/MS workflow approach enables aggregation of separate methods into a single analysis, improving productivity, while the high capacity ion exchange columns can withstand higher sample loading enabling the analysis of lower concentrations of polar analytes in the more difficult, but relevant matrices, such as leek and cereal products. The MS/MS ion ratios, retention time stabil- ity, recovery and precision data were in compliance with the with the EU SANTE/11813/2017 method performance criteria. Presenter: Alexander Semyonov, Thermo Fisher Scientific, Austin, TX, USA, Email: alexander.semyonov@thermofisher.com

86 SEPTEMBER 6–12, 2019 SHERATON DENVER DOWNTOWN HOTEL