Determination of sodium nifurstyrenate and nitrovin residues in edible food by liquid chromatography-tandem mass spectrometry after ultrasound-assisted extraction.

A specific and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of nitrovin and sodium nifurstyrenate residues in muscle and liver of swine and chicken and in muscle of fish. Sample preparation procedure includes ultrasound-assisted extraction with acetonitrile, defatting with n-hexane and final clean-up with solid phase extraction (SPE) on Oasis HLB cartridges. The analytes were detected in multiple reaction monitoring (MRM) under negative scan mode acquiring two diagnostic product ions for sodium nifurstyrenate and under positive mode for nitrovin. The averaged decision limits (CCα; α 1%) ranged 0.09-0.26 μg/kg while the detection capability (CCβ; β 5%) was 0.33-0.97 μg/kg in the tissues. Reasonable recoveries (71-110%) spiked in muscle and liver showed excellent relative standard deviation (RSD). The validated method was simple, rapid, sensitive, and complied with the regulations for the determination of nitrovin and sodium nifurstyrenate residues in food matrices.