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 (R²) 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 (R² = 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.

The evaluation of the catalytic capacity of catalysts is indispensable research, as catalytic capacity is a crucial factor to dictate the efficiency of heterogeneous Fenton catalysis. Herein, we obtained cigarette tar-methanol extracts (CTME) by applying methanol to cigarette tar and found that CTME could cause CL reactions with Fe²⁺/H₂O₂ systems in acidic, neutral, and alkaline media. The CL spectrum experiment indicated that the emission wavelengths of the CTME CL reaction with Fe²⁺/H₂O₂ systems were about 490 nm, 535 nm, and 590 nm. Quenching experiments confirmed that hydroxyl radicals (•OH) were responsible for the CL reaction for CTME. Then the CL property of CTME was applied in-situ to rapidly determine the amounts of •OH in tetrachloro-1,4-benzoquinone (TCBQ)/H₂O₂ system in acidic, neutral and alkaline media, and the CL intensities correlated the best (R² = 0.99) with TCBQ concentrations. To demonstrate the utility of the CTME CL method, the catalytic capacity of different types and concentrations of catalysts in heterogeneous Fenton catalysis were examined. It was found that the order of CL intensities was consistent with the order of degradation efficiencies of Rhodamine B, indicating that this method could distinguish the catalytic capacity of catalysts. The CTME CL method could provide a convenient tool for the efficient evaluation of the catalytic capacity of catalysts in heterogeneous Fenton catalysis.