The development of a reagentless electrode system for the determination of
nitrate is presented. The approach is based upon the deposition of a macrop
orous copper deposit which shows marked selectivity for nitrate ion under m
ildly acidic conditions (pH 3) with a linear range extending from 10 to 200
mu M nitrate. Fabrication of the layer is both inexpensive and simple and
is relatively substrate independent (Cu, Au, glassy carbon) as the response
is attributed to the electrodeposited support. The influence of potential
interferents such as chloride, nitrite and complexing agents such as citric
acid were examined. In particular, the reduction of nitrite was found to o
ccur at potentials significantly less negative than those required for nitr
ate reduction and as a result clear resolution of both voltammetric peaks i
s obtainable. The lack of direct interference between the two ions combined
with wide peak separation (200 mV) provides a system that may offer some p
otential in speciation studies. The analytical applicability of the propose
d system was demonstrated through the standard addition determination of ni
trate in a number of authentic samples with the nitrate concentrations inde
pendently corroborated using established Griess assay spectroscopic protoco
ls.