Determination of submicromolar concentrations of ammonia in natural waters by a standard addition method using a gas‐sensing electrode1

Abstract

A standard addition technique using a gas‐sensing electrode with a modified electrode filling solution provides a rapid and convenient method suitable for both field and laboratory measurement of ammonia. The method has a detection limit of 0.2 µ M of NH 3 , a precision of ±0.1 µ M of NH 3 , and no measurable salt error. Calibration is stable for a period of days and analytical rates of 15 samples per hour are possible.