biostudies-literatureXie JThe National Key Research and Development Program of ChinaNational Natural Science Foundation of China3765https://www.ebi.ac.uk/biostudies/studies/S-EPMC10180504biostudies-literatureUnknown28(9)Although dicofol has been widely banned all over the world as a kind of organochlorine contaminant, it still exists in the environment. This study developed a high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) detection technique for dicofol, an environmental pollutant, for the first time using in-source fragmentation. The results confirmed that <i>m</i>/<i>z</i> 251 was the only precursor ion of dicofol after in-source fragmentation, and <i>m</i>/<i>z</i> 139 and <i>m</i>/<i>z</i> 111 were reasonable product ions. The main factors triggering the in-source fragmentation were the H⁺ content and solution conductivity when dicofol entered the mass spectrometer. Density functional theory can be used to analyze and interpret the mechanism of dicofol frMolecules (Basel, Switzerland)Spontaneous In-Source Fragmentation Reaction Mechanism and Highly Sensitive Analysis of Dicofol by Electrospray Ionization Mass Spectrometry.PMC10180504320724662021YFD1700300Liu XZheng YGuo YZhu LXie JJiang HMa YZhang LMao LfalseSpontaneous In-Source Fragmentation Reaction Mechanism and Highly Sensitive Analysis of Dicofol by Electrospray Ionization Mass Spectrometry.Although dicofol has been widely banned all over the world as a kind of organochlorine contaminant, it still exists in the environment. This study developed a high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) detection technique for dicofol, an environmental pollutant, for the first time using in-source fragmentation. The results confirmed that <i>m</i>/<i>z</i> 251 was the only precursor ion of dicofol after in-source fragmentation, and <i>m</i>/<i>z</i> 139 and <i>m</i>/<i>z</i> 111 were reasonable product ions. The main factors triggering the in-source fragmentation were the H⁺ content and solution conductivity when dicofol entered the mass spectrometer. Density functional theory can be used to analyze and interpret the mechanism of dicofol fr2023-01-01T00:00:00Z2023 Apr2025-04-26T17:23:46.642Z2025-04-06T15:29:43.139ZS-EPMC101805043717517110.3390/molecules28093765