Identification of the C3H7 moiety of isopropyl‐ and propylphosphonates by electrospray tandem mass spectrometry

Structure analysis of phosphorus compounds within the framework of the Chemical Weapons Convention requires the specific identification of alkyl substituents on phosphorus. In this work the distinction of the P-propyl substituent in propylphosphonic acid derivatives by electrospray tandem mass spectrometry was investigated. P-Isopropyl and P-n-propyl groups were readily distinguished and a mechanistic proposal was given, based on labelling experiments. The findings were applied to the identification of the P-propyl moiety of two V-agents, O-ethyl S-[2-(dialkylamino)ethyl/propylphosphonothiolates, and to a degradation product of a G-agent, propyl propylphosphonate.