(PUF) [17–19] were found to be suitable sorbents
for solid phase spectrophotometry, the latter being an
excellent matrix for rapid sorption of a wide variety
of analytes from water [10]. The application of PUF
preconcentration technique coupled with the Griess
color reaction described in this paper, and is thought
useful for determination of traces of nitrite and nitrate
in natural waters, especially in potable waters.