Massive cluster impact ionization on a four sector tandem mass spectrometer

High energy gycerol cluster ions from an electrohydrodynamic ion gun have been used as a primary ion beam to generate secondary ions of proteins with molecular weights up to 29 kDa and oligonucleotides. The technique not only demonstrated good performance in the picomole/nanomole range for the desorbtion of highly polar and fragile molecules such as proteins and deoxyoligonucleotides, but it also allowed the observation of a non‐covalent complex in the form of a deoxyoligonucleotide duplex. We have also shown that it is feasible to carry out structural analysis of oligonucleotides by collisional activation in a four sector tandem instrument.