Comparators
The Comparator is the choice of many when a mid-range cost solution is required for a single or low number of parameters.
A sample of water is taken in two tubes, reagents added to one tube - the other is the blank. The parameter specific disc is put into the comparator with the two tubes and the colour is the sample tube is compared to that on the disc.
There are currently two different styles of comparator available on the market, plastic and glass, with a significant price difference between the two:
- Plastic discs with a continuous colour scale and limited shelf life.
- Glass discs with individual glass standards for each division, guaranteed for life.
The accuracy of the comparator has been accepted for many years as a reasonable solution for field analysis giving an accuracy in the region of 10 - 20%. Again the result is only guaranteed to be within one division either way of the actual result.
Comparator tests are most often used for chlorine, bromine, chlorine dioxide and molybdate.
- Easily portable
- Mid-range cost
- Simple methodology
- Quick result