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A high-throughput, QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) sample preparation and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method has been developed and validated for the determination of 191 pesticides in vegetation and fruit samples. Using identical LC analytical column and MS/MS instrumentation and operation(More)
A method for the determination of 35 acid herbicides in food matrices was developed, validated, and implemented. It utilizes a modified QuEChERS extraction procedure coupled with quantitation by liquid chromatography tandem mass spectrometry (LC-MS/MS). The acid herbicides analyzed are all organic carboxylic acids, including the older chlorophenoxy acid(More)
Seven FDA pesticide laboratories collaborated to develop and validate an LC-MS/MS method to determine 173 pesticides in <20 min. The average determination coefficient (r²) was >0.99 for all but two compounds tested. The limits of detection were <20 ng/mL for all compounds and <10 ng/mL for 363 of the 368 transitions reported. The method was used to(More)
The effectiveness of cysteine hydrochloride (Cys-HCl) as a preservative of ethylenethiourea (ETU) in product matrixes and during analysis was studied. ETU recoveries were adversely affected by certain product matrixes when fortified directly into the product. Recoveries in 8 selected food items were 0-92% when analyzed 30 min after fortification and 0-51%(More)
A liquid chromatographic-electrochemical method for the determination of ethylenethiourea (ETU) residues uses methylene chloride in the cleanup. Distilled-in-glass grade methylene chloride produced erratic ETU recoveries ranging from 0 to 106% for vacuum rotary evaporation of the solvent. ETU recoveries were found to be dependent on the bottle of methylene(More)
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