2.3. Recommended procedure
5.5 mL of 0.02 mol L
−1
of KI, and 3 mL of 0.1 mol L
−1
sulfuric acid
were added to a 25 mL volumetricflask. Then an aliquot of the nitrite
(so that its concentration would be in the range of 8–120 ng mL
−1
)
and 8 mL of Triton X-100 (5%) were added and made up to the mark
with water and left to stand for 30 min. This solution was then placed
in a thermostat bath at 80 °C for 25 min. After the separation of the
two phases, the solution was placed in an ice bath for the surfactant
rich phase to become viscose. Then the dilute phase was removed by
decantation and the surfactant rich phase was diluted with water in a
5 mL volumetricflask. The absorbance of the solution was measured
at 365 nm. A blank solution was also run using water instead of
nitrite.