Determination of N-methyl-1,3-propanediamine in bovine muscle by liquid chromatography with triple quadrupole and ion trap tandem mass spectrometry detection.

Morantel, pyrantel and their drug-related metabolites in food of animal-origin are regulated as sum of residues which may be hydrolysed to N-methyl-1,3-propanediamine (NMPA). In this study, an isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS) method with pentafluoropropionic acid anhydride (PFPA) derivatization was developed for the determination of NMPA in bovine muscle. A stable isotope labeled internal standard N-methyl-d(3)-3,3'-d(2)-propane-1,3-diamine (NMPA-d(5)) was synthesized as internal standard.

Determination of closantel and rafoxanide in animal tissues by online anionic mixed-mode solid-phase extraction followed by isotope dilution liquid chromatography tandem mass spectrometry.

A rapid and high-throughput isotope dilution LC-MS/MS method with online sample pre-concentration and clean-up using anionic mixed-mode SPE was described for the determination of closantel and rafoxanide in edible bovine and ovine tissues. Tissue samples were extracted with acetonitrile and acetone mixture (60:40, v/v). Sample pre-concentration, clean-up and analysis were completed simultaneously with the online MAX SPE LC-MS/MS system.

Quantitative analysis of closantel and rafoxanide in bovine and ovine muscles by high-performance liquid chromatography with fluorescence detection.

An HPLC method with a fluorescence detector (HPLC-FLD) was described for the quantitative determination of closantel and rafoxanide in bovine and ovine muscles. A structural analog closely related to rafoxanide, viz., N-[4-(4-chlorophenoxy)phenyl]-2-hydroxy-3,5-diiodobenzamide, was synthesized as an internal standard.

Screening of closantel and rafoxanide in animal muscles by HPLC with fluorescence detection and confirmation using MS.

A sensitive and selective LC-FLD method was described for determination of closantel and rafoxanide in bovine and ovine muscles. Bovine and ovine muscles were extracted with ACN and acetone mixture (80:20, v/v). After cleanup with Oasis MAX SPE cartridges, the sample was analyzed by LC-FLD using the control point approach.