Iron (II, III) oxide/multi-walled carbon nanotube composite as solid-phase extraction sorbent followed by ultra-high performance liquid chromatography tandem mass spectrometry for simultaneous determination of zearalenone and type A trichothecenes in Salviae miltiorrhizae Radix et Rhizoma (Danshen).

For the first time, a reliable solid-phase extraction (SPE) procedure using iron (II, III) oxide (FeO)/multi-walled carbon nanotube (MWCNT) composite as sorbents was proposed for purification and enrichment of zearalenone (ZEA) and four type A trichothecenes (T-2 toxin (T-2), HT-2 toxin (HT-2), neosolaniol (NEO) and diacetoxyscirpenol (DAS)) in Salviae miltiorrhiza Radix et Rhizoma (Danshen). The FeO/MWCNT composite was synthesized by assembling FeO with MWCNT by sonication through an "aggregation wrap" mechanism and several key parameters affecting the performance of SPE procedure such as the composition of sample loading solutions, washing and elution solvents were thoroughly investigated. After optimization, 2% acetonitrile aqueous solution as the loading solution, 5% methanol aqueous solution as the washing solution and acetone containing 0.5% formic acid as the elution solvent presented an excellent purification efficiency for the five targets in Danshen. Under the optimal sample pretreatment conditions followed by analysis with ultra-high performance liquid chromatography-tandem mass spectrometry, satisfactory linearity (R≥0.991), high sensitivity (limit of quantification in the range of 1.20-4.80μgkg), good recovery (73.7-91.9%) and acceptable precision (RSD, 2.1-13.3%) were obtained. The applicability of the validated method was further verified in real Salviae miltiorrhiza Radix et Rhizoma samples.