THE ELECTROSPRAY MASS-SPECTRA OF PHOSPHORIC-ACID, METHYLPHOSPHONIC ACID AND ITS ALKYL ESTERS, AND THEIR COMPLEXES WITH ALKALI AND ALKALI-EARTH METAL-IONS

Positive and negative ion electrospray mass spectra were obtained dire ctly from water/alcohol solutions for phosphoric acid, methylphosphoni c acid and its mono( 1,2,2-trimethylpropyl) ester and bis(l-methylethy l) ester, Collisional activation and tandem mass spectrometry (MS/MS) of both the cations and anions of the phosphonates resulted in hydroge n rearrangement with loss of neutral alkenes to give the respective me thylphosphonic acid anion (m/z 95) and methylphosphonic acid cation (m /z 97), Solutions of this series of compounds, which comprise a neutra l, mono-basic, di-basic and tri-basic ligand, were complexed with alka li and alkali earth metal ions, The peaks observed in the positive ion electrospray mass spectra, and their propensity for fragmentation und er collisional activation, were found to be consistent with the predic ted stabilities of the complexes.