Reagents in liquid form are undoubtedly the fastest detection agents because they dissolve most quickly in the water sample and develop their chemical effect. They are usually used with several components in a measurement method and are added to the sample one after the other with a pipette. This requires dexterity, because both the size and the number of drops influence the colour complex that forms in the water sample. Therefore, the highest accuracy is required in dosing - and accuracy in counting the drops. The shelf life of liquids is limited: Temporary contact with the air when opening, sunlight, higher temperatures have a detrimental effect.
If the optimum storage conditions are observed, Lovibond® DPD and Phenolred solutions can be used for up to 2 years.