Nitrate by ISE
Method Abstract #52
Scope and Application
This method is a variation of Standard Methods 4500-NO3– D. It determines the concentration of nitrate ions in a water sample.
The concentration of nitrate is determined by a nitrate ion selective electrode. After calibrating with known standards, the sample’s response can be compared to the calibration curve and a concentration determined. Both the standards and the samples are pre-treated with ionic strength adjuster (ammonium sulfate) to ensure that the background response from each sample is similar.
Sample Calibration Curve
*Data for this measuring range was obtained using laboratory prepared standards formulated from potassium nitrate. The measuring range may be increased by using auto-dilution.
**The Method Detection Limit (MDL) was determined based on data obtaining a coefficient of variance better than 30%. Results may differ depending on laboratory practices and sample matrix.