Reactions of the trimethylsilyl ion with 1,2‐cyclopentanediol isomers in the collision region of a triple quadrupole instrument

Ion‐molecule reactions with the trimethylsilyl ion were used to distinguish between cis ‐ and trans ‐1,2‐cyclopentanediol isomers. The ion kinetic energy of [Si(CH 3 ) 3 ] + was varied from 0 eV to 15 eV (center of mass frame of reference). At low ion kinetic energies (<4 eV), there are significant differences in the relative stabilities and decomposition behavior of the adduct ions [M + Si(CH 3 ) 3 ] + . The cis ‐1,2‐cyclopentanediol isomer favors decomposition of [M + Si(CH 3 ) 3 ] + to yield the hydrated trimethylsilyl ion [Si(CH 3 ) 3 OH 2 ] + at m / z 91. For the trans isomer, the formation of the hydrated trimethylsilyl ion is an endothermic process with a definite threshold ion kinetic energy.