H/D exchange reactions of protonated diglycine; an electrospray ionization-flow tube reactor experiment

The H/D exchange reactions of protonated diglycine, GLY(2)H(+), with ND3 were studied under thermal conditions with a combination of an electrospray ion source and a flow tube reactor. Consecutive exchange of the five labile hydrogens is observed with increasing flow rate of ND3. Collision complexes corresponding to the consecutive H/D exchanges are monitored for the first time. The role of multiple exchanges in a single collision event with ND3 is probed. Results will be discussed in the light of previously suggested mechanisms of H/D exchange of GLY(2)H(+) with deuterated ammonia. (C) 1999 Elsevier Science B.V.