Nitriet HR PP / M273
Ferrous Sulfate Method
Instrument-Specific Information
The test can be performed on the following instruments. The required cuvette and the absorption range of the photometer are also indicated.
| Instruments | Cuvette | λ | Measurement Range |
|---|---|---|---|
| XD 7000, XD 7500 | Ø 24 mm | 585 nm | 2 - 250 mg/L NO₂⁻ |
Reagents
Required materials (partly optional):
| Reagents | Packaging Unit | Order No. |
|---|---|---|
| VARIO Nitri NT-2 F10 | Powder / 100 pcs. | 530280 |
Application Areas
- Cooling water
- Boiler water
Procedure for Determining Nitrite HR with Powder Packet
Select the method in the instrument.
- Fill the 24 mm cuvette with 10 mL of sample. [image: Filling cuvette with sample]
- Close the cuvettes. [image: Closing cuvette]
- Place the sample cuvette in the measurement chamber. Pay attention to the positioning. [image: Placing cuvette in chamber]
- Press the ZERO button. [image: Pressing ZERO button]
- Close the cuvettes. [image: Closing cuvette]
- Remove the cuvette from the measurement chamber. [image: Removing cuvette from chamber]
- Add one Vario Nitri 3 F10 powder packet. [image: Adding powder packet]
- Mix the contents by inverting (20 sec.). [image: Mixing contents]
- Place the sample cuvette in the measurement chamber. Pay attention to the positioning. [image: Placing cuvette in chamber]
- Press the TEST (XD: START) button. [image: Pressing TEST button]
- Wait for 10 minutes for the reaction time. [image: Stopwatch indicating 10 minutes]
- After the reaction time, the measurement is performed automatically. The display shows the result in mg/L NO₂⁻.
Evaluation
The following table indicates that the output values can be converted to other citation forms.
| Unit | Calculation Formula | Conversion Factor |
|---|---|---|
| mg/l | N | 1 |
| mg/l | NO₂⁻ | 3.2846 |
Chemical Method
Ferrous Sulfate Method
Calibration Function for Third-Party Photometers
Conc. = a + b•Abs + c•Abs² + d•Abs³ + e•Abs⁴ + f•Abs⁵
| Ø 24 mm | 10 mm | |
|---|---|---|
| a | 1.9063 · 10⁻¹ | 1.9063 · 10⁻¹ |
| b | 1.4494 · 10⁻² | 3.1162 · 10⁻² |
| c | ||
| d | ||
| e | ||
| f |
Method Validation
| Limit of detection | 1 mg/L |
| Quantification limit | 3 mg/L |
| End of measurement range | 250 mg/L |
| Sensitivity | 145 mg/L / Abs |
| Confidence intervals | 4.7 mg/L |
| Standard deviation procedure | 2.0 mg/L |
| Coefficient of variation procedure | 1.55% |
