蒽醌类化合物在大气压化学电离源中的离子化行为研究

Ionization Behavior of Anthraquinones in Atmospheric-pressure Chemical Ionization Source

对蒽醌类化合物在大气压化学电离源(atmospheric-pressure chemical ionization,APCI)中的离子化行为进行了研究,首次提出了APCI源中可以存在分子内氢键,更好地解释了质子转移和电荷转移2种离子化方式在APCI源中的竞争,是对APCI源离子化机理的补充。分别比较研究了7种蒽醌类化合物在流动注射进样时正离子和负离子模式下的离子化规律及HPLC-MS进样时的离子化规律。通过改变流动相的流速和比例改变离子源中反应离子的种类和数量,研究离子化环境对蒽醌类化合物电离方式的影响。蒽醌类化合物在正离子模式下主要是得质子的离子化过程,在负离子模式下表现出明显的质子转移和电子转移2种离子化方式的竞争,电子转移的离子化方式在蒽醌类化合物中占明显优势。APCI源中质子转移和电荷转移方式哪种占优势除受化合物本身结构的影响外,离子化环境中的反应离子对其也起到很重要的作用。

The ionization behavior of anthraquinones in atmospheric-pressure chemical ionization（AP- CI） source was studied. The formation of intramolecular hydrogen bond of anthraquinone molecules in APCI source was firstly proposed to explain the competition action between proton transfer and charge transfer in APCI source. The ionization regular pattern of anthraquinones was studied by flow injection sampling in positive and negative ion modes in APCI source, and by HPLC sampling in negative ion mode in APCI source. Effects of ionization environment, including reaction ions type and amounts in APCI source, on ionization mode of anthraquinones were examined by changing the flow rate and mobile phase proportion. The result indicated that the proton transfer was a predominant process in positive ion mode, while a competition existed between proton transfer and charge transfer in negative ion mode in APCI source. The charge transfer was considered to be the predominant process for anthraquinones in APCI. Thus, the ionization mode in APCI source was not only affected by the structure of compounds, but also affected by the types and amounts of reactive ions in ionization environment.