Gas-gap sensors for the determination of nitrogen oxides and nitrites

Two new air-gap sensors with different indicator electrodes for the determi nation of nitrogen oxides and nitrites are described. The linear range of t he electrode functions E = f(lg[NO2]) and E=f(-lg[NaNO2]) for the sensor on the base of a combined glass pH electrode was 5 x 10(-8)-1 x 10(-3) M, and on the base of combined NO3--ion-selective electrode it was 5 x 10(-6)-1 x 10(-3) M. The calibration curve slopes were 58.5 mV in both cases. The des igned sensors were used for nitrite determination in some environmental sam ples. (C) 2000 Elsevier Science B.V. All rights reserved.