How to use pH indicator strips

The pH of a liquid indicates whether a liquid is acidic, neutral or alkaline. In some cases, this is important to know, for example when you want to determine whether a disinfectant is still effective. To determine the pH of a liquid, you can use pH indicator strips. In this article, our specialist provides more information about the use of pH indicator strips. 

How does a pH indicator strip work?

pH indicator strip is a strip of litmus paper with which you can measure the pH value of a liquid. The substance in the paper causes the paper to show a different colour at different acidities. The official pH scale is from 0 to 6, where 0 is very acidic and 6 very alkaline. Some pH indicator strips can measure a pH from 0 to 6, but there are also strips that can measure only acid or only alkaline substances.

How to use a pH indicator strip

Dip the strip for two seconds in the fluid which you want to control, then wait for ten seconds. Because the strip contacts an acidic or alkaline substance, the strip discolours. The more acidic the fabric, the redder the strip becomes and the more alkaline the fabric, the bluer the strip becomes. Using the indicator scale with the different colours on the box, you can determine how acidic or alkaline the liquid you measured is.

In the video below, product specialist Jan Willem Keijzer measures the pH of the disinfectant in a disinfection mat using a pH indicator strip. 

The difference between pH strips and a pH meter

A pH meter usually contains a computer and generally gives results to a hundredth of an inch. This is not the case with pH indicator strips, these are less accurate. pH indicator strips are therefore very useful to quickly determine whether a solution is acidic, neutral or alkaline, but are not suitable for accurate measurements. 

Note: if you are colour blind, it can be difficult to read a pH indicator strip correctly. 

Questions about pH indicator strips
Do you have any questions about the use of pH indicator strips, or would you like to get advice? Please contact product specialist Jan Willem Keijzer, or ask your question using the contact form below.

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