Residual contaminations in food are increasingly a public and a regulatory concern. Contamination from disinfection processes and perchlorate from contaminated soil and water are well known. More recently, ionic herbicides (glyphosate, glufosinate) and fungicides (methylbromide, fosetyl-Al), under the category of polar pesticides, have also become a concern. Ion chromatography (IC) with suppressed conductivity detection is designed for the determination of ionic compounds in a variety of samples, including food, and therefore is better suited for separating these compounds than other chromatography techniques. Additionally, IC is a direct determination method unlike GC which requires labor intensive and costly analyte derivatization. IC with suppressed conductivity detection combined with serial detection by electrospray ionization single quadrupole mass spectrometry (ESI-MS) provides additional selectivity with mass confirmation needed with these critical ions. Here we combine the determinations of select polar pesticides, perchlorate, and disinfection byproducts in homogenized pear and green bean samples into one method. All analytes (2.5 µL) are separated by IC on a 2 x 250 mm anion-exchange column within a 14 min run using an electrolytically generated hydroxide gradient from 10 to 75 mM at 40 oC and 0.35 mL/min. The ions were detected serially by suppressed conductivity and ESI-MS in full scan from 50-350 m/z and in selected ion monitoring (SIM) modes. The method with MS detection had good reproducibility (RSDs &lt; 3) and accuracy (80-120% recoveries). With calibration ranges from 5 µg/L to 10 mg/L, most of the ions exhibited responses fitting a quadratic equation. Sensitivity using a 2.5 µL injection ranged from 5 to 100 µg/L.

Determination of select anionic herbicides, fungicides, disinfection byproducts, and perchlorate in homogenized food samples using ion chromatography coupled with electrospray ionization-mass spectrometry (IC-ESI-MS)

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.