Fenton or Fenton‐like reactions are ubiquitous in nature, and the hydroxyl radicals (·OH) generated in these reactions are accountable for a plethora of oxidation processes both in the environment and in vivo. Among these oxidation reactions, lipid oxidation initiated by ·OH radicals has long been oversimplified as a peroxidation mechanism, but in reality, it is a highly complicated process that can result in a large variety of products. Using the unique field‐induced droplet ionization mass spectrometry (FIDI‐MS) methodology that is capable of selective sampling of amphiphilic molecules that reside at the air–water interface, here, we show distinct mechanisms from the ultraviolet (UV)‐enhanced Fenton oxidations of two phospholipids, POPC and POPG, even though these two lipids possess the same functional groups that are vulnerable to ·OH attack. We postulate that it is the different packing densities that determine the permeability of ambient NO molecules into the monolayers, resulting in highly distinct reaction pathways and products. We anticipate that this work will be a wake‐up call that the lipid peroxidation mechanism is sometimes taken for granted and that lipid oxidation can be subtly affected by various factors that deserves deeper investigations.

中文翻译：

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超越脂质过氧化：观察到由空气-水界面处的紫外线增强的Fenton反应引发的POPC和POPG氧化的不同机制

Fenton或类Fenton反应本质上无处不在，这些反应中产生的羟基自由基（·OH）是环境和体内过多氧化过程的原因。在这些氧化反应中，由·OH自由基引发的脂质氧化作为过氧化机理一直以来都被过分简化，但实际上，它是一个高度复杂的过程，可能导致产生各种各样的产物。使用独特的场致液滴电离质谱（FIDI-MS）方法，该方法能够选择性采样位于空气-水界面的两亲分子，在这里，我们展示了与紫外线（UV）增强的Fenton氧化作用不同的机理尽管这两种脂质具有易受OH攻击的相同官能团，但它们却含有两种磷脂，即POPC和POPG。我们假设是由不同的堆积密度决定周围的NO分子进入单层的渗透性，从而导致高度不同的反应途径和产物。我们预计这项工作将引起人们的警醒，有时认为脂质过氧化机制是理所当然的，脂质氧化会受到各种因素的微妙影响，值得进一步研究。