Trace Analysis of Fenbutatin Oxide in Soil and Plant- and Animal-Derived Foods Using Modified QuEChERS Coupled with HPLC-MS/MS.

A modified QuEChERS method in combination with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was first developed for the determination of fenbutatin oxide in six types of samples (soil, tobacco, rice, milk, pork liver, and pork). Fenbutatin oxide was extracted with acetonitrile containing 1% formic acid (v/v) and purified by dispersive solid-phase extraction using primary secondary amine (PSA) and quantitatively analyzed by HPLC-MS/MS. In the range of 0.005-1 mg/kg, a good linear relationship exists between the concentration of fenbutatin oxide and the peak area, giving a coefficient of determination (R 2) of >0.99. The recoveries of fenbutatin oxide at three spiked levels were 79.04-97.12% with the relative standard deviations (RSDs) of 3.30-10.96%, and the limit of quantification (LOQ) was 0.007 mg/kg. In addition, the developed method is consistent with the reference method (R 2 = 0.9896, n = 40). The method is demonstrated to be convenient and reliable for the routine monitoring of fenbutatin oxide in soil and plant- and animal-derived foods.