Nitrate Nitrogen Calculator
Definition: In the cadmium reduction method, nitrate is reduced to nitrite. The resulting nitrite is measured colorimetrically. Nitrite originally present in the sample must be subtracted when nitrate alone is required.
A = absorbance after cadmium reduction
b = calibration curve intercept
m = calibration curve slope
DF = dilution factor
NO₂-N = nitrite nitrogen originally present
Method basis: Standard Methods for the Examination of Water and Wastewater, Method 4500-NO₃⁻ E — Cadmium Reduction Method. Nitrate is reduced to nitrite and measured colorimetrically.