For data analysis, the raw spectra were deconvoluted using a 27000:37000 Da window and 1 Da resolution. The signal from masses 27000:30000 and 34000:37000 (which contained no peaks) was averaged and subtracted from the whole signal. The peaks of each species were integrated using a 100 Da window in every direction (reducing the window down to 10 Da did not change the results significantly).