3.7. Analytical performance
The analytical performance of the cloud point extraction system was
evaluated in terms of limit of detection, linear range and reproducibility.
The calibration was performed under optimum conditions in order to
establish the working range. The calibration graph was linear in the
range of 8–120 ng mL
−1with an equation of the line A=0.010 C+
0.049 where A is the absorbance and C is the nitrite concentration in
ng mL
−1
. The reproducibility calculated as the relative standard
deviations of ten replicate measurements of 60 ng mL
−1
of nitrite was
3.40% and the limit of detection based on three times the standard
deviation of the blank (3Sb) was 6.0 ng mL
−1
(n=10).