Liquid chromatographic fluorescence method for multiresidue determination of thiabendazole and 5-hydroxythiabendazole in milk.
A novel liquid chromatographic multiresidue method has been developed for quantitation of thiabendazole (TBZ), the metabolite 5-hydroxythiabendazole (5-OH-TBZ), and the sulfate conjugate of 5-hydroxythiabendazole (5-HSO4-TBZ) in raw cow's milk. The 5-HSO4-TBZ is hydrolyzed quantitatively under acidic conditions to 5-OH-TBZ. TBZ and 5-OH-TBZ are extracted from milk at pH 8.0 with ethyl acetate followed by cleanup of the extract on a cation-exchange solid-phase extraction column. Analytes are quantitated by liquid chromatography with a cation-exchange stationary phase and fluorescence detection. Recoveries from raw cow's milk samples fortified with TBZ and 5-OH-TBZ or TBZ and 5-HSO4-TBZ at 0.05 to 2 ppm ranged from 87 to 103% for TBZ, 98-109% for 5-OH-TBZ, and 96-115% for 5-HSO4-TBZ (quantitated as 5-OH-TBZ). The assay provides a simple, rapid, and sensitive multiresidue method for monitoring total residues of TBZ, 5-OH-TBZ, and 5-HSO4-TBZ in milk.
Arenas
R V
RV
Merck & Co., Inc., Merck Research Laboratories, Three Bridges, NJ 08887-0450, USA.
Johnson
N A
NA
D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D005453:Fluorescence; D008892:Milk / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*; D013827:Thiabendazole / Q000031:analogs & derivatives* / Q000032:analysis*
D010573:Pesticide Residues; C035151:5-hydroxythiabendazole; D013827:Thiabendazole