Ig. Torro et al., FLOW-INJECTION BIAMPEROMETRIC DETERMINATION OF NITRATE (BY PHOTOREDUCTION) AND NITRITE WITH THE NO2- I- REACTION/, Analytica chimica acta, 366(1-3), 1998, pp. 241-249
An unsegmented continuous-flow method for the determination of nitrite
and nitrate is proposed. Nitrate is photoreduced by UV irradiation wi
th a low-pressure 8 w mercury lamp. The nitrite in the sample and that
resulting from the photoreduction of nitrate are used to oxidize iodi
de ion. Tri-iodide thus formed is detected biamperometrically in exces
s iodide by using a flow-cell furnished with two platinum electrodes p
olarized at 100 mV. The limits of detection, throughput and reproducib
ility (n=26) thus achieved for nitrite and nitrate are 25 and 50 mu g
l(-1), 27 and 25 h(-1), and 1.2 and 1.6%, respectively. The proposed m
ethod was used to determine nitrate and nitrite in natural waters, was
te waters, soils, meat products and fertilizers. (C) 1998 Elsevier Sci
ence B.V.