title: Validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of sulfonamides, trimethoprim and dapsone in muscle, egg, milk and honey.
abstract: A quantitative multi-residue method that includes 13 sulfonamides, trimethoprim and dapsone was developed and validated according to Commission Decision 2002/657/EC for muscle, milk egg and honey samples. For all matrices, the same extraction procedure was used. Samples were extracted with an acetone/dichloromethane mixture and cleaned up on aromatic sulfonic acid (SO3H) SPE cartridges. After elution and concentration steps, analytes were identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Data were acquired according to the multiple reaction-monitoring approach (MRM) and analytes were quantified both by the isotope dilution and the matrix-matched approaches calculating the response factors for the scanned product ions. The developed method shows good linearity, specificity, precision (repeatability and within-laboratory reproducibility), and trueness. Estimated CCβ for sulfonamides ranged between 5.6 and 8.2 µg kg(-1) for eggs, between 11.1 and 69.9 µg kg(-1) for milk, between 64.7 and 87.9 µg kg(-1) for muscle, and between 2.7 and 5.3 µg kg(-1) for honey. CCβ values for dapsone were 3.1, 0.6, 0.7 and 1.5 µg kg(-1) and for trimethoprim were 3.1, 6.7, 81.7 and 3.0 µg kg(-1) calculated for eggs, milk, muscle and honey, respectively. Recovery for all matrices was in the range from 89.1% and 109.7%. In matrix effect testing, no significant deviations were found between different samples of muscle and milk; however, a matrix effect was observed when testing different types of honey. The validation results demonstrate that the method is suitable for routine veterinary drug analysis and confirmation of suspect samples.
authors.affiliation: a Laboratory for Residue Control, Department of Veterinary Public Health , Croatian Veterinary Institute , Savska cesta 143, HR-10000 Zagreb , Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Varenina
authors.affiliation: a Laboratory for Residue Control, Department of Veterinary Public Health , Croatian Veterinary Institute , Savska cesta 143, HR-10000 Zagreb , Croatia.
authors.forename: Nina
authors.initials: N
authors.lastname: Bilandžić
authors.affiliation: a Laboratory for Residue Control, Department of Veterinary Public Health , Croatian Veterinary Institute , Savska cesta 143, HR-10000 Zagreb , Croatia.
authors.forename: Božica Solomun
authors.initials: BS
authors.lastname: Kolanović
authors.affiliation: a Laboratory for Residue Control, Department of Veterinary Public Health , Croatian Veterinary Institute , Savska cesta 143, HR-10000 Zagreb , Croatia.
authors.forename: Đurđica
authors.initials: Đ
authors.lastname: Božić
authors.affiliation: a Laboratory for Residue Control, Department of Veterinary Public Health , Croatian Veterinary Institute , Savska cesta 143, HR-10000 Zagreb , Croatia.
authors.forename: Marija
authors.initials: M
authors.lastname: Sedak
authors.affiliation: a Laboratory for Residue Control, Department of Veterinary Public Health , Croatian Veterinary Institute , Savska cesta 143, HR-10000 Zagreb , Croatia.
authors.forename: Maja
authors.initials: M
authors.lastname: Đokić
authors.affiliation: a Laboratory for Residue Control, Department of Veterinary Public Health , Croatian Veterinary Institute , Savska cesta 143, HR-10000 Zagreb , Croatia.
authors.forename: Ines
authors.initials: I
authors.lastname: Varga
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D003622:Dapsone / Q000032:analysis*; D004531:Eggs / Q000032:analysis*; D006722:Honey / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D009132:Muscles / Q000737:chemistry*; D015203:Reproducibility of Results; D013449:Sulfonamides / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014295:Trimethoprim / Q000032:analysis*
chemical_list: D013449:Sulfonamides; D003622:Dapsone; D014295:Trimethoprim
keywords: Sulfonamides; dapsone; liquid chromatography mass spectrometry; trimethoprim; validation; various matrices