Negative ion mass spectrometry and the detection of carbonyls and HCN front clover

We have demonstrated that negative ion-chemical ionization mass spectrometr y (NI-CIMS) can be used to distinguish several isomeric volatile organic co mpounds (VOCs) that are emitted from wounded plants. Reaction chemistry wit h HO-, hydrogen/deuterium exchange patterns, and collision-induced dissocia tion spectra allow identification of the isomers. Laboratory studies of emi ssions from wounded clover using NI-CIMS show several previously detected V OCs, but also clearly demonstrate the emission of HCN. This compound is pre sumably formed by the decomposition of cyanogenic glycosides which also for m aldehyde and ketone byproducts. These results suggest that NI-CIMS may be a valuable tool for investigating VOCs and HCN release from vegetation.