title: Determination of 22 triazole compounds including parent fungicides and metabolites in apples, peaches, flour, and water by liquid chromatography/tandem mass spectrometry.
abstract: A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed for the determination of 14 parent triazole fungicides and 8 of their metabolites found in apples, peaches, flour, raw water, and tap water. The triazole fungicides chosen for this multiresidue method development project included propiconazole, fenbuconazole and its RH-9129 and RH-9130 metabolites, cyproconazole, difenoconazole, tebuconazole and its HWG 2061 metabolite, hexaconazole, bromuconazole (both stereoisomers), epoxiconazole, tetraconazole, triticonazole and its RPA-404886 and RPA-406341 metabolites, triadimefon, triadimenol, and myclobutanil. Of special concern to the U.S. Environmental Protection Agency were the metabolites common to all triazole fungicides: free triazole, 1,2,4-triazole (T), and its 2 conjugates: triazolylalanine (TA) and triazolylacetic acid (TAA). These metabolites were the primary focus of this project. All samples we cleaned up by a combination of C18 solid-phase extraction (SPE), mixed-mode cationic SPE, and mixed-mode anionic SPE columns. A triple-stage quadrupole mass spectrometer, equipped with electrospray ionization in the positive-ion mode, was used to determine the compounds of interest. T, TA, and TAA were quantitated using isotopically labeled internal standards (IS), in which the 1,2,4-triazole ring had been synthesized by using 13C and 15N (IS_T, IS_TA, and IS_TAA). These isotopically labeled internal standards were necessary to correct for matrix effects. The T, TA, and TAA metabolites were quantitated at the 25-50 parts-per-billion (ppb) level in food commodities and at 0.50 ppb in water. Recoveries were 70-101% from apples, 60-121% from peaches, 57-118% from flour, 75-99% from raw water, and 79-99% from tap water.
authors.affiliation: U.S. Environmental Protection Agency, Office of Pesticide Programs, Biological and Economic Analysis Division, Analytical Chemistry Branch, 701 Mapes Rd, Fort George G. Meade, MD 20755-5350, USA. schemerhorn.patricia@epa.gov
authors.forename: Patricia G
authors.initials: PG
authors.lastname: Schermerhorn
authors.forename: Paul E
authors.initials: PE
authors.lastname: Golden
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Krynitsky
authors.forename: William M
authors.initials: WM
authors.lastname: Leimkuehler
mesh_terms: D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D005433:Flour / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D005659:Fungicides, Industrial / Q000032:analysis* / Q000145:classification / Q000378:metabolism; D027845:Malus / Q000737:chemistry; D027861:Prunus / Q000737:chemistry; D012680:Sensitivity and Specificity; D014230:Triazoles / Q000032:analysis* / Q000145:classification / Q000378:metabolism; D014867:Water / Q000737:chemistry
chemical_list: D005659:Fungicides, Industrial; D014230:Triazoles; D014867:Water