Application of ISFETs for pH measurement in rain droplets

The analysis of chemical components in single raindrops, including pH, is expected to give a new information about air pollution. This paper presents the first attempt of an ISFET application for the pH measurement in raindrops. The investigated rain samples are originated from 11 different rain events including even individually collected (using a liquid nitrogen) droplets. The results of pH measurements in raindrops with the pH ISFET are compared with the conventional glass electrode measurements in bulk rain samples. The observed raindrop size dependence of the pH value is discussed.