Nitrate and nitrite absorb sufficiently over the wavelength
range from 190 to 225 mm to allow direct UV detection.
For sensitive detection of the analytes, the electrolyte buffer
used should have low absorbance at the detection wavelength
(Guan et al. 1996). In this work, tetraborate was
selected as the electrolyte anion because its mobility is
similar to that of the analytes of interest; it presents “high
transparency” and its solutions are stable during storage and
continuous analysis