Caldur® Chlorine dioxide – Photometric
Determination of chlorine dioxide in water photometrically (0.05-0.5 mg/l)
Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for Caldur® Chlorine dioxide – Photometric:
See also:
CALDUR® Chlorine Dioxide Test Set – Photometric
What is chlorine dioxide measured for?
Chlorine dioxide (ClO₂) is a highly effective disinfectant that is used in drinking water treatment, the food industry and industrial water treatment. Compared to chlorine, chlorine dioxide has the advantage that it is also effective at higher pH values and does not form chloramines that impair the taste.
Precise monitoring of the chlorine dioxide concentration is crucial, as values that are too low mean inadequate disinfection, while concentrations that are too high pose health risks and can lead to undesirable by-products.
The limit value for drinking water in Germany is 0.2 mg/l (Drinking Water Ordinance). In practice, a residual value of 0.05 – 0.1 mg/l is often aimed for in order to ensure a continuous disinfection effect in the pipe network.
How does the test set work?
The CALDUR® Chlorine Dioxide Test Set – Photometric works according to the proven DPD method (diethyl-p-phenylenediamine). After adding two reagents to the water sample, a characteristic pink to violet coloration develops within about 1 minute, the intensity of which is proportional to the chlorine dioxide concentration.
The measured value is precisely determined photometrically with the WINLAB Data Line photometer, which guarantees objective and reproducible results.
Advantages of the CALDUR® test set
- Fastest analysis in just 1 minute
Ideal for on-site measurements – enables immediate process adjustments
- High sensitivity from 0.05 mg/l
Perfect for compliance with the Drinking Water Ordinance and residual value monitoring
- 140 provisions per set – economical in continuous use
Cost-efficient for regular inspections in waterworks and industry
- Photometric measurement for objective results
Precise laboratory analyses with WINLAB Data Line Photometer – eliminates subjective color deviations
- Optimized for WINLAB Data Line photometer
Stored calibration curves enable fast and precise measurements
- Complete documentation possible
Automatic storage of all measured values with date and time for seamless quality assurance
Areas of application
Carrying out the measurement:
- Fill water sample into test tube up to the 10 ml mark
- Add 5 drops of reagent A (DPD) and swirl briefly
- Add 3 drops of reagent B (buffer) and mix
- After waiting 1 minute, place the test tubes in the photometer
- Perform photometric measurement – concentration is automatically calculated and displayed
💡 Tip for best results
For precise measurements, the water sample should be clear. Always use the same test tube for zero adjustment and measurement. The reaction time of 1 minute should be strictly adhered to, as the coloration can intensify over time. Carry out a zero adjustment with distilled water before the first measurement.
⚠️ Important notes
- Bring reagents to room temperature before use
- Observe waiting time of 1 minute exactly for precise measurement results
- The simultaneous presence of free chlorine can lead to adulteration
- Rinse test tubes thoroughly with distilled water after use
- Keep test tubes clean and dry on the outside for accurate photometer measurement
Measuring range
| Parameters | Measuring range | Wavelength |
|---|---|---|
| Chlorine dioxide (ClO₂) | 0.05 – 0.5 mg/l | 520 nm |
The photometric measurement enables an objective, precise determination without subjective color perception. The photometer measures the absorbance at a defined wavelength and automatically calculates the concentration.
Number of possible provisions
You can carry out 140 measurements with a CALDUR® chlorine dioxide test kit.
This refers to the quantity of reagents contained.
Measuring accuracy and reproducibility
Accuracy: ± 2 % of the measured value (for photometric measurement)
Reproducibility: Very good if the application instructions are followed
Interference: Free chlorine can influence the result. If chlorine and chlorine dioxide are present at the same time, the combined test set should be used. Turbidity of the sample can falsify the result (filter the sample if necessary).
What to do if measured values are out of range?
Measured value > 0.5 mg/l
| Dilution | Procedure | Calculation of the measured value |
|---|---|---|
| 1:1 | 5 ml sample + 5 ml distilled water | Measured value × 2 |
| 1:4 | 2 ml sample + 8 ml distilled water | Measured value × 5 |
| 1:9 | 1 ml sample + 9 ml distilled water | Measured value × 10 |
Measured value < 0.05 mg/l
Measured value is below the detection limit. This may mean that there is insufficient disinfection. Check the dosage of your disinfection system.
Specifications at a glance
| Property | Value |
|---|---|
| Parameters | Chlorine dioxide (ClO₂) |
| Item number | 31-073272 |
| Method | Photometric (DPD method) |
| Measuring principle | Photometric measurement with WINLAB Data Line Photometer |
| Measuring range | 0.05 to 0.5 mg/l |
| Wavelength | 520 nm |
| Analysis duration | 1 minute |
| Number of provisions | 140 |
| Number of reagents | 2 (reagent A, B) |
| Accuracy | ± 2 % of the measured value |
| Scope of delivery |
|---|
| 2 reagent bottles (reagent A, B) with detailed labeling |
| 1 test tube with 10 ml scale |
| Detailed operating instructions (DE/EN) |
| Safety data sheets for all reagents |
Reagent details
| Reagent | Volume | Shelf life | Notes |
|---|---|---|---|
| Reagent A (DPD) | 30 ml | 24 months (24M) | Shake before use, store in a cool place |
| Reagent B (buffer) | 10 ml | 24 months (24M) | 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 away from direct sunlight.
Compatible photometer
WINLAB Data Line Photometer
- Wavelength range: 380 – 810 nm
- 9 LED wavelengths incl. 520 nm for chlorine dioxide
- Saved calibration curve for chlorine dioxide
- Automatic calculation of the concentration
- Data memory for up to 1000 measured values
- IrDA interface for data transmission
Additional information
| Packaging | Hinged lid box, Refill pack |
|---|
Flyer
Operating instructions
Instructions for use
Instructions for use
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