Figure 2.
MALDI-TOF mass spectra of SOS (40 pmol) acquired using 70 mg/mL ImCHCA matrix in positive-ion (panel A) and negative-ion (panel B) reflectron modes. Upper mass spectra in both panels A and B were obtained with samples in the absence of ammonium salt, and the lower mass spectra in both panels were recorded from samples containing ammonium acetate.