In an initial investigation into the electrospray ionisation ion trap mass spectrometry (ESI/ITMS) of simple organophosphate esters we reported that in one of the collision induced fragmentation steps of protonated dimethyl methylphosphonate (DMMP), formaldehyde was eliminated with a concomitant partial scrambling of the methyl group attached to the phosphorus and a methoxy group. The present paper describes a further investigation of this reaction. Three novel isotopomers of DMMP were used for this study and their synthesis and properties are reported. A mechanism for the formaldehyde elimination and scrambling of the methyl groups is proposed and supported by a kinetic analysis of a limiting case. During this study ‘black holes’ were found to occur in one of the ITMS instruments used and it is shown that these could lead to severe distortions in the amounts of product ions observed. A brief analysis of this observation is presented
在对简单有机
磷酸酯的电喷雾电离离子阱质谱 (ESI/ITMS) 的初步研究中,我们报道了在质子化
甲基膦酸二甲酯 (
DMMP) 的碰撞诱导断裂步骤之一中,
甲醛被消除,同时伴随着部分扰乱甲基连接至
磷和甲氧基。本文描述了对该反应的进一步研究。本研究使用了
DMMP 的三种新型同位素异构体,并报告了它们的合成和性质。提出了消除
甲醛和扰乱甲基的机制,并得到了极限情况的动力学分析的支持。在这项研究中,我们发现所使用的一台 ITMS 仪器中出现了“黑洞”,并且表明这可能会导致观测到的产物离子数量严重失真。对这一观察结果进行了简要分析