Phosphate testing in Water

The contamination of waterways with Phosphate from Agricultural run-off causes environmental issues e.g. growth of Algae which reduce the Oxygen levels of natural waters. The most common test involves a colorimeter and hazardous reagents. We offer a simple safe and low cost test which can be carried out in the field or in the laboratory.

The Method:

The concentration of Phosphate in aqueous samples is determined indirectly by the use of a Phosphate
ISE and the addition of two reagents to the sample being measured.
Please note:
1. This method requires the use of a QP459 Ion Meter
2. Calibration requires the use of EDT directION Phosphate Standards only.
3. The test requires 50ml of sample and 5 ml additions of reagent A and Reagent B prior to
measurement.
4. The test is for Phosphate concentration of between 0 and 120ppm. For concentrations higher
than this please dilute the sample with deionised water.

Procedure:
1. Select the Phosphate Mode on the QP459 Meter
2. Ensure the Phosphate ISE has been conditioned by standing in the low standard for 20 minutes.
3. Measure out 50ml of the 10ppm and 100ppm standards into separate 100ml beakers.
4. Add 5ml (using the green Syringe) of reagent A to each standard. Stir and wait for 1 minute.
5. Add 5ml (using red syringe) of reagent B to each standard. Stir and wait for 1 minute.
6. Insert the ISE into the 10ppm Standard and follow the CAL procedure on the QP459 meter.
7. Insert the ISE into the 100ppm standard for a 2 point calibration.
8. Follow the instructions on the QP459 to measure the samples
9. Measure out 50ml of each sample into 100ml plastic beakers. Add 5ml of Reagent A (Green Top)
with the syringe provided to each sample. Stir and leave for 1 minute. Add 5ml of Reagent B (Red
Top) with the syringe provided to each sample. Stir and leave for 1 minute.

After measuring the samples rinse electrode with DI water and store dry. Ensure the green and red
syringes are used for their own reagents only. Seal all standards and reagent after use.
Once the reagents have been added the samples cannot be re analysed. 

Take a look at the Phosphate Meter Kit.