Vessel-inside-vessel microwave-assisted acid digestion was developed for the analysis of samples with high-unsaturated fat content. For the first time, thermal decomposition of (NH₄)₂S₂O₈ solutions was evidenced for SO₃ generation in situ and gas-phase modification in pressurized digestion flasks. NMR analysis demonstrated the oxidative effect of SO₃ on olefin double bonds despite incomplete mineralization of oil samples. In this context, (NH₄)₂S₂O₈ decomposition was used in association with HNO₃ solutions for sample digestion and mineral determination in edible oils (safflower, coconut, flaxseed, and chia). For all oils, dissolved organic carbon (DOC) contents lower than 5% m m^-1 were obtained under optimum conditions: 210 °C with an irradiation time of 40 min, 7.0 mol L^-1 HNO₃ and 2.0 mol L^-1 (NH₄)₂S₂O₈ in 0.9 mol L^-1 H₂SO₄. Thus, a DOC reduction of about 70% was reached compared to digestions using only HNO₃ at the same conditions. Additionally, a time reduction of up to three-fold was achieved compared to typically demanding edible oil digestions. The proposed method allowed the determination of As, Cd, Cr, Mn, Ni, and Pb in edible vegetable oil samples by ICP-MS. Accuracy was evaluated against the reference method, and no significant difference was observed (p = 0.05), with wide linear ranges and good linearity (r ≥ 0.999) and LOD ranging from 0.48 (As) to 2.41 (Cd) μg L^-1.

开发了容器内容器微波辅助酸消解技术，用于分析具有高不饱和脂肪的样品。首次证明了（NH ₄）₂ S ₂ O ₈溶液的热分解可在加压消化瓶中原位产生SO ₃并进行气相改性。NMR分析表明，尽管油样品矿化不完全，SO ₃对烯烃双键的氧化作用。在这种情况下，将（NH ₄）₂ S ₂ O ₈分解与HNO ₃结合使用用于食用油（红花，椰子，亚麻籽和嘉）中样品消化和矿物质测定的解决方案。对于所有油，在以下最佳条件下获得的溶解有机碳（DOC）含量均低于5％mm ^-1：210°C，照射时间为40分钟，7.0 mol L ^-1 HNO ₃和2.0 mol L ^-1  （NH ₄）在0.9 mol L ^-1  H ₂ SO _4中的2 S ₂ O ₈。因此，与仅使用HNO _3的消化相比，DOC减少了约70％在相同条件下。此外，与通常要求的食用油消化相比，可节省多达三倍的时间。该方法可以通过ICP-MS测定食用植物油样品中的砷，镉，铬，锰，镍和铅。精度与参考方法评价，并且没有观察到显著差异（p  = 0.05），具有宽的线性范围和良好的线性度（[R  ≥0.999）和LOD范围从0.48（As）的2.41（CD）微克大号^-1。