Abstract by Jiuzhi Gao
Chemistry and Biochemistry
Opposite polarity electrical charge on electrosprayed bacterial spores: implications for electrospray mechanism
Electrospray ionization (ESI) is a commonly used soft ionization technique in mass spectrometry. Maze et al. observed a phenomenon of bipolar fission in which about 1% of the droplets in a positive electrospray were measured to have a negative charge. We have previously demonstrated that ESI can produce desolvated, de-agglomerated, bacterial spores with either positive or negative charges on their surface. However, under some conditions, we observe as many as 23.7% of electrosprayed spores carry a charge with polarity opposite to the ESI tip. This effect is present for both positive spray and negative spray. An asymmetric 2-stage image charge detector eliminates ambiguity of charge measurement. ESI experiments with amino-terminated polystyrene beads of similar size showed no such characteristics.