A simple nitrate sensor system using titanium trichloride and an ammonium electrode

A simple sensor system using titanium trichloride (TiCl3) and an ammonium electrode was developed for nitrate determination. The sensor measures the ammonium ion resulting from the reduction of nitrate by titanium trichloride in hydrochloric acid. The advantages of this system are that it is easy to operate and free from interference due to ammonium ion already present in the samples. The sensor system has a dynamic range from 0.1 to 30 mg/l NO3− and a detection limit of 0.05 mg/l NO3−, with a response time of less than 10 min for the entire procedure. The sensor had a relative standard deviation (R.S.D.) of less than 1.97% after more than 10 successive measurements of 1.0 mg/l nitrate. The sensor is unaffected by other possible interfering compounds in nature waters, such as FeCl3, NaCl and Na2SO4 at concentrations of 30 mg/l. The effects of titanium trichloride solution concentration, reaction time and temperature were also investigated. Furthermore, several river water samples were examined to demonstrate the application of this system to environmental monitoring.