Ammonium adduct ion in ammonia chemical ionization mass spectrometry: 2—Mechanism of elimination of neutrals from the ammonium adduct ion

The mechanism of elimination of ROH (R = H or CH 3 ) from the ammonium adduct ion, [M+NH 4 ] + , of 1‐adamantanol and its methyl ether is examined by using linked‐scan metastable ion spectra and by measuring the dependence of the peak intensity ratio [M+NH 4 ] + /[M+NH 4 ROH] + on ammonia pressure. For 1‐adamantanol both S N i and S N 1 reactions are suggested in metastable ion decomposition, while only the S N 1 mechanism is operative in the ion source. For 1‐adamantanol methyl ether the S N 1 reaction predominates both in metastable ion decomposition and in the ion source reaction.