Abstract:

Lubaberone （LUB） is the first U S Food and Drug Administration （FDA） approved feed additives for reducing gaseous emissions from animals or their wastes， and the intake of animal-derived foods is an important source of human exposure to LUB. However， the lack of applicable analytical methods makes it difficult for regulatory authorities to monitor LUB in animal-derived foods. There is an urgent need to establish efficient and accurate methods for the analysis of LUB in animal-derived foods. In this study， a method was developed for the determination of LUB from six types of typical animal-derived foods （beef， bovine liver， bovine fat， mutton， sheep liver and sheep fat） by ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）. The effects of extraction solvent types， extraction methods， extraction time and purification cartridges on the recovery of LUB were investigated， and the optimal conditions for sample pretreatment were confirmed. The homogenized samples were extracted using 0.5% formic acid acetonitrile via ultrasonication for 10 min， and then filtered by high-speed centrifugation， and the extracted solution was cleaned using SPE with a PRiME HLB cartridge. The LUB was separated on a Shim-pack GIST C18-AQ chromatographic column （100 mm×2.1 mm， 2.7 μm） with 0.1% formic acid aqueous solution-0.1% formic acid acetonitrile as mobile phases at a flow rate of 0.3 mL/min， and detected in positive ion switching mode （ESI⁺） with multiple reaction monitoring （MRM） scanning， and quantitatively analyzed using the external standard method. Under the optimized experimental conditions， LUB in different animal-derived food matrices showed good linearity within their respective linear concentration ranges with the correlation coefficients （r） greater than 0.99. The limits of detection （LODs） and the limits of quantification （LOQs） were 0.4‒1.0 μg/kg and 1.0‒2.0 μg/kg， respectively. The recoveries of LUB spiked at low， medium and high levels ranged from 81.5% to 116.5% with relative standard deviations （RSDs） of 2.0%‒8.2%. The method is simple， rapid and highly sensitive， which can enable the analysis of LUB residues in animal-derived foods， and provides analytical technology support for the daily detection of LUB residues in imported and exported animal-derived foods.

Key words: lubabegron （LUB）, solid-phase extraction （SPE）, ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）, beef