English Abstract A flow injection method (FIA) for the determination of
hydronium in rainwater has been developed and optimized. The lower limit of
detection is 2.7 mumol/L-3O+ and the upper limit of detection is 180
mumol/L H-3O+. The standard deviation in the working range is less then 1.5
mumol/L H-3O+. Comparison with the titrimetric method showed a small
difference of -2.1 mumol/L H-3O+. Comparison with the hydronium
concentration calculated from the pH showed a significant difference of 3.6
mumol/L H-3O+.
