CALDUR® Nitrate – Colorimetric
Determination of nitrate in water using a color chart (1-50 mg/l NO₃-)
Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for CALDUR® Nitrate – Colorimetric:
See also:
CALDUR® Nitrate Test Set – Colorimetric
What is nitrate measured for?
Nitrate (NO₃-) is one of the most important parameters in drinking water analysis. It enters the groundwater primarily through agricultural fertilization and wastewater discharges. The limit value for drinking water is 50 mg/l NO₃- (Drinking Water Ordinance).
Elevated nitrate concentrations are harmful to health, as nitrate can be converted to nitrite in the body, which impairs the oxygen supply. A low nitrate level is particularly important for infants and small children.
In environmental analysis, nitrate is an Reagent for the pollution of water bodies by nutrients and can contribute to eutrophication.
How does the test set work?
The CALDUR® Nitrate Test Set – Colorimetric is based on the NED method (N-(1-naphthyl)-ethylenediamine). After adding two reagents to the water sample, a characteristic pink to violet coloration develops within 6 minutes, the intensity of which is proportional to the nitrate concentration.
The measured value is determined by direct color comparison with a supplied color chart.
Advantages of the CALDUR® test set
- Practical measuring range 1 – 50 mg/l NO₃-
Covers the entire drinking water range up to the limit value
- 200 provisions per set
Particularly economical for regular checks
- Quick analysis in just 6 minutes
Results directly on site
- Proven NED method
Reliable and reproducible results
- Robust plastic housing with hinged lid
Safe transportation and protection of reagents
Areas of application
Carrying out the measurement:
- Fill water sample into test tubes up to the 10 ml mark
- Add 5 drops of reagent A and mix
- Add 3 drops of reagent B and mix
- Wait for 6 minutes reaction time
- Perform color comparison with color chart
Tip for best results
The measurement should be carried out promptly after sampling. If nitrite interference is suspected, the sample can be pre-treated with amidosulphuric acid. Samples with high chlorine concentrations (>5 mg/l) should be pre-treated with sodium thiosulphate.
Important notes
- Adhere exactly to the reaction time of 6 minutes
- Avoid direct sunlight during the measurement
- High nitrite concentrations can influence the result
- Do not warm the sample – this can falsify the result
- Thoroughly rinse the test tube with the sample before each measurement
Measuring range
| Measuring level | Description |
|---|---|
| 1 mg/l | Very low concentration (pale pink) |
| 5 mg/l | Low concentration (light pink) |
| 10 mg/l | Slightly increased concentration (pink) |
| 20 mg/l | Medium concentration (deep pink) |
| 30 mg/l | Increased concentration (pink-violet) |
| 50 mg/l | Drinking water limit value (violet) |
If the color lies between two fields, you can form the mean value
(e.g. between 10 and 20 mg/l = approx. 15 mg/l).
Number of possible destinations
You can carry out 200 measurements with one CALDUR® nitrate test kit.
This refers to the quantity of reagents contained.
Measuring accuracy and reproducibility
Readability: ± 1 color level
Reproducibility: Very good if the application instructions are followed
Interference: Nitrite in high concentrations can influence the result. Highly colored samples make color readings more difficult. At high chlorine concentrations, the reaction can be slightly disturbed.
What to do if measured values are out of range?
Measured value > 50 mg/l
| Verduction | Execution | Calculation of the measured value |
|---|---|---|
| 1:1 | 5 ml sample + 5 ml nitrate-free water | Measured value × 2 |
| 1:4 | 2 ml sample + 8 ml nitrate-free water | Measured value × 5 |
Measured value < 1 mg/l
The measured value is below the detection limit. This indicates a very low nitrate load.
Specifications at a glance
Reagents (2 reagents)
| Property | Value |
|---|---|
| Parameters | Nitrate (NO₃-) |
| Item number | 31-072340 |
| Method | Colorimetric (NED) |
| Measuring principle | Color comparison with 6-stage color chart |
| Measuring range | 1 to 50 mg/l NO₃- |
| Color scale | 6 measuring levels (1 / 5 / 10 / 20 / 30 / 50 mg/l) |
| Duration of analysis | 6 minutes |
| Number of provisions | 200 |
| Number of reagents | 2 |
| Packaging | Hinged lid box |
| Packaging size | 103 x 91 x 36 mm |
| weight | approx. 140 g |
| Scope of delivery |
|---|
| 2 reagent bottles (reagent A, reagent B) with detailed labeling |
| 1 test tube with 10 ml scale |
| 1 color card with 6 measuring levels |
| Detailed operating instructions (DE/EN) |
| Safety data sheets for all reagents |
| Robust hinged lid box (103 x 91 x 36 mm) |
Reagent details
| Reagent | Volume | Shelf life | Notes |
|---|---|---|---|
| Reagent A (reducing agent) | 30 ml | 24 months (24M) | Nitrate reduction reagent, shake before use |
| Reagent B (NED color reagent) | 15 ml | 24 months (24M) | NED reagent, shake before use |
Shelf life: The shelf life starts from the date of manufacture (printed on the bottle).
After opening, the reagents should be used within 12 months.
Store the test kit in a dry, cool place (10-25°C) and protected from direct sunlight.
Additional information
| Packaging | Hinged lid box, Refill pack |
|---|---|
| Product category | Testset |
Flyer
Operating instructions
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