The combination of an analysis time of less than 1 min per sample and the possibility to acquire accurate masses under high mass resolving power (HR) makes the DART-HRMS technique an effective tool for rapid qualitative screening of antiparasitic veterinary drugs. Additionally, the results obtained in this study demonstrated the feasibility of this approach to quantify target analytes at levels down to 1 µg kg(-1) for benzimidazolic compounds in milk and 0.25 mg kg(-1) for coccidiostats in chicken feed.
Drugs that are used as medicines and also as growth promoters in veterinary care are considered as emerging environmental contaminants and in recent years concern about their potential risk to ecosystems and human health has risen. In this paper we used a method based on liquid chromatography/electrospray tandem mass spectrometry to analyze eight coccidiostatic compounds: diclazuril, dinitrocarbanilide (the main metabolite of nicarbazin), robenidine, lasalocid, monensin, salinomycin, maduramicin and nasarin. Multiple-stage mass spectrometry (MSn) based on the precursor ions [M+Na]+ (polyether ionophores), [M+H]+ (robenidine) and [M-H]- (diclazuril and dinitrocarbanilide) was used to study the fragmentation of these compounds. MSn data and genealogical relationships were used to propose a tentative assignment of the different fragment ions. Loss of water, decarboxylations, ketone beta-cleavages and rearrangement of cyclic ethers and amide groups were some of the fragmentations observed for these compounds. Liquid chromatography with a sub-2 microm particle size column was coupled to tandem mass spectrometry (LC/MS/MS) allowing the separation of these compounds in less than 7 min. Method detection limits ranging from 11 to 71 ng L(-1) and run-to-run values in terms of relative standard deviation (RSD) (up to 12%) were obtained.
In this work a fast liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method was developed for the analysis of toltrazuril, a coccidiostatic drug, and its metabolites in meat food products. The applicability of atmospheric pressure chemical ionization (APCI) and heated electrospray ionization in both positive and negative modes was studied. APCI in negative mode provided the best results and the base peak originated from the loss of CF(3) (toltrazuril and toltrazuril sulfone) and CHF(3)* (toltrazuril sulfoxide) was used as the precursor ion in MS/MS. A fast LC separation on a C(18) Fused-Core column was used together with the APCI-MS/MS method developed using enhanced mass resolution mode (highly selective selected reaction monitoring, H-SRM) to improve the sensitivity and selectivity for the analysis of these compounds in food samples. A simple sample treatment based on an extraction with acetonitrile and a cleanup with a C(18) cartridge was used. The LC-MS/MS (H-SRM) method showed good precision (relative standard deviation lower than 10%), accuracy, and linearity and allowed the determination of these compounds in food samples down to the parts per billion level (limits of detection between 0.5 and 5 microg kg(-1)).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.