The EI pos. ion and CI neg. ion mass spectra of alkyl dialkoxyphosphinylacetates are reported. The CI neg. ion mass spectra were recorded using CH4 as reagent gas. Both the pos. and neg. ion mass spectra of alkyl dialkoxyphosphinylacetates show characteristic [M + H]+ and [M - H]- ion peaks, while [M - H]- ions are base peaks for all compounds In the EI spectra, the main decomposition pathways involve successive loss of CnH2n, H2O, CO2 and then CH2CO. A series of fragment ion peaks containing phosphorus and scissions of the P-O and P-C linkages are observed in NCI mass spectra.

Key words: ACETIC ACID ESTER, ALKOXYL GROUP, MASS SPECTROGRAPHY, PHOSPHONIC ACID ESTER, CHEMICAL BONDS, ANION, CHEMICAL IONIZATION SOURCE MASS SPECTROMETRY, FRACTURE MECHANISM, ELECTRON BOMBARDMENT