CALDUR® Phosphate LR – Colorimetric
Phosphate determination in the water using a color chart (0.25-10 mg/l PO₄³-)
Private customers can also find our range in our partner store Ampha-Analyse.
Reagent for CALDUR® Phosphate LR – Colorimetric:
See also:
CALDUR® Phosphate LR Test Set – Colorimetric
What is phosphate measured for?
Phosphate (PO₄³-) is an essential nutrient, but in high concentrations it leads to the eutrophication of water bodies. Excessive phosphate inputs from fertilizers, wastewater or detergents promote excessive algae growth and can severely disrupt the ecological balance.
In drinking water treatment, phosphate is specifically dosed as corrosion protection to protect pipes from limescale deposits and corrosion. The optimum dosing range is typically 2-5 mg/l PO₄³-.
Phosphate elimination is a central process step in wastewater treatment plants. Regular monitoring of the phosphate concentration in the effluent ensures compliance with the limit values.
How does the test set work?
The CALDUR® Phosphate LR test kit is based on the molybdate blue method. Phosphate reacts with molybdate in an acidic solution to form phosphomolybdenum blue. The resulting blue coloration is proportional to the phosphate concentration.
The measured value is determined by direct color comparison with a 6-stage color chart supplied.
Advantages of the CALDUR® test set
- Measuring range 0.25 – 10 mg/l PO₄³-
Ideal for drinking water, waste water and water monitoring
- 200 determinations per set
Particularly economical for regular checks
- Quick analysis in just 5 minutes
Immediate results on site
- Easy handling with 2 reagents
No measuring devices required
- Robust plastic housing with hinged lid
Safe transportation and protection of reagents
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 and mix
- Add 5 drops of reagent B and mix
- Wait for 5 minutes reaction time
- Perform color comparison with color chart
Tip for best results
For best results, the water sample should be clear and free of suspended solids.
If the water is cloudy, pre-filtration with a filter paper is recommended.
The response time of 5 minutes should be strictly adhered to.
Important notes
- Bring reagents to room temperature before use (20-25 °C)
- Adhere exactly to the reaction time of 5 minutes
- Avoid direct sunlight during the measurement
- Rinse test tubes thoroughly with the sample before each measurement
- Silicate can influence the measurement in high concentrations
Measuring range
| Measuring level | Description |
|---|---|
| 0.25 mg/l | Very low concentration (weak blue) |
| 0.5 mg/l | Low concentration (light blue) |
| 1.0 mg/l | Slightly increased concentration (blue) |
| 2.0 mg/l | Medium concentration (strong blue) |
| 5.0 mg/l | High concentration (dark blue) |
| 10.0 mg/l | Very high concentration (deep blue) |
If the color is between two fields, you can form the mean value
(e.g. between 1.0 and 2.0 mg/l = approx. 1.5 mg/l).
Number of possible determinations
You can carry out 200 measurements with one CALDUR® Phosphate LR 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: Silicate in high concentrations (> 50 mg/l) can slightly increase the measured value. Strongly colored or cloudy samples can make color readings more difficult.
What to do if measured values are out of range?
Measured value > 10 mg/l
| Dilution | Procedure | Calculation of the measured value |
|---|---|---|
| 1:4 | 2 ml sample + 8 ml phosphate-free water | Measured value × 5 |
| 1:9 | 1 ml sample + 9 ml phosphate-free water | Measured value × 10 |
Measured value < 0.25 mg/l
measured value is below the detection limit of this test kit. This is generally not critical and indicates that the phosphate concentration is very low.
Specifications at a glance
| Property | Value |
|---|---|
| Parameters | Phosphate (PO₄³-) |
| Item number | 31-072410 |
| Method | Colorimetric (molybdate blue) |
| Measuring principle | Color comparison with 6-stage color chart |
| Measuring range | 0.25 to 10 mg/l PO₄³- |
| Color scale | 6 measuring levels (0.25 / 0.5 / 1.0 / 2.0 / 5.0 / 10.0 mg/l) |
| Duration of analysis | 5 minutes |
| Number of determinations | 200 |
| Number of reagents | 2 |
| Packaging | Hinged lid box |
| Packaging size | 103 x 91 x 36 mm |
| weight | approx. 160 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 (molybdate) | 15 ml | 24 months (24M) | Shake before use |
| Reagent B (reducing agent) | 15 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.
Additional information
| Packaging | Hinged lid box, Refill pack |
|---|---|
| Product category | Test kit |
Flyer
Operating instructions
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