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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Commodity Protection and Quality Research » Research » Publications at this Location » Publication #419734
Research Project: Improved Systems-based Approaches that Maintain Commodity Quality and Control of Arthropod Pests Important to U.S. Agricultural Production, Trade and Quarantine

Location: Commodity Protection and Quality Research

Title: Capillary electrophoresis quantification of fluoride residues following sulfuryl fluoride treatment of grain ¿

Author
item Hall Iv, Wiley
item Corbett, Stephen
item STIGLMEIER, KYLIE - Oak Ridge Institute For Science And Education (ORISE)

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: The accurate and sensitive analysis of fluoride residues in agricultural commodities is critical for the regulatory approval of sulfuryl fluoride (SF), ensuring that the use of SF is in compliance with safety and environmental regulations. Fluoride is often used as a measure of SF exposure because the volatility of parent compounds makes its concentration in the treated commodity dynamic. Even in situations where the dose of SF greatly exceeds the label maximum, no SF residue may be detectable several days after treatment. Fluoride residues, in contrast, are stable. The method is automated and accurate, generates very low amounts of waste, and could be expanded to include other components of interest, which is not possible with the ISE method. Unfortunately, fluoride is not an easyily compounded to measure in most ag. commodities, the current preferred method, measurement by ion sensitive electrode (ISE), is slow and requires a relatively high amount of manual labor. In this study, capillary electrophoresis with contactless conductivity detection (CE-C4D) is shown to quickly and accurately quantify fluoride levels in SF treated corn. The method is automated and accurate, generates very low amounts of waste, and has the potential to be expanded to include other inorganic anions of interest, which is not possible with the ISE method.

Technical Abstract: Capillary electrophoresis coupled with contactless conductivity detection (CE-C4D) is presented as an alternative method to fluoride ion sensitive electrodes for the analysis of fluoride in food. CE-C4D was used to quickly and accurately determine the residue of fluoride resulting from treating corn with the postharvest fumigant sulfuryl fluoride using a buffer containing 50 mM acetic acid, 55 mM triethylamine, and 5% glycerol as background electrode (BGE). Fortified corn samples showed good accuracy and precision with a recovery of 94% and relative standard deviation of 16% at 1.00 mg / kg fluoride and a sub-ppm detection limit (0.50 ppm).