Abstract
A pH meter equipped with a device to provide a continuously renewed liquid junction between a sample solution and an internal solution of reference electrode was used for the pH measurement of rain waters. Stable responses were obtained within 1 minute and the pH could be determined with the coefficient of variation of 0.1% even when the electric conductivity of sample solution was below 20μS/cm.
Differences in pH between conventional and present methods were increased for the rain water samples whose electric conductivities were below 20μS/cm. Ion balance and electric conductivity balance calculations on 169 rain water samples suggested that the present method gave more reliable pH values than the conventional one.
