Ethylenediamine as a liquid chemical reagent to probe hydrogen bonding and host‐guest interactions with crown ethers in an ion trap tandem mass spectrometer

Ethylenediamine (EDA) was used as a novel liquid chemical reagent to probe hydrogen bonding and host‐guest interactions with crown ether derivatives in an ion trap mass spectrometer (ITMS). Selective ion/molecule reaction product ions were generated by reactions of EDA with oxygenated and aza‐crown ethers. For the oxygenated crown ethers, glycols and dimethylglycols, ion/molecule reactions led to the formation of the protonated molecules ([M+H] + ) and adduct ions including [M+30] + , [M+44] + and [M+61] + . The aza‐crown ethers produced [M+H] + , [M+13] + and [M+27] + ions. Collisionally activated dissociation (CAD) experiments were applied to probe the binding strength of these ion/molecule reaction products. CAD results indicated that all these hydrogen‐bonding complexes are weakly bound except for the [M+44] + ion of 18‐crown‐6, since all the complexes dissociate to the protonated polyether and/or protonated EDA. Fragmentation of the [M+H] + ions under CAD conditions indicates the extensive covalent bond cleavage of the protonated crown ether skeleton. Copyright © 2004 John Wiley & Sons, Ltd.