The electro-DPD test for free chlorine is coming to SenseItAll.
BACKGROUND
The DPD (N,N-diethyl-p-phenylenediamine) method, introduced in 1957, is widely used for testing chlorine levels in water. It involves liquid tests using a dropper bottle and photometer. DPD strip tests in the market are not true dip-and-read tests but transfer agents for DPD powder, where the powder reacts with chlorine in water, producing a pink color that is then compared to a color chart or measured with a device.
The photometric DPD equipment today is manual and not Cloud-enabled, with several manual steps, including:
- Begin by rinsing the test tube with the water sample, leaving a small amount in the tube.
- Crush the DPD No. 1 tablet in the remaining water sample until thoroughly crushed.
- Add 10ml of the test solution, mix, and seal the tube with the cap.
- Choose Phot 7 on the Photometer.
- Follow the usual Photometer instructions to take a reading.
The obtained result represents the free chlorine residual in milligrams per liter (mg/l).
Excessive chlorine concentration, exceeding 10 mg/l, may lead to the fading of the pink color developed in the DPD test, resulting in a potentially inaccurate negative reading or a lower-than-anticipated result. If the test solution appears colorless or only faintly pink, it suggests a potential high chlorine level. To verify this, conduct the test again using a sample diluted with water that is free from chlorine, checking for any signs of bleaching.
SENSEITALL (SIA) electro-DPD
The SIA platform from ZP is EVK/MVP for anyone looking to digitize the DPD test for 2024. The SIA platform from ZP is an OEM solution for those who want to integrate DPD testing into their product or service offering. The SIA platform offers a test-to-cloud solution and so offers revenue on the sensors, the meter, and the data.
