What turbidimeter would be recommended for colored samples?

Document ID

Document ID TE8920

Published Date

Published Date 07/12/2021
Print
Question
What turbidimeter would be recommended for colored samples?
Summary
Measuring turbidity in colored samples.
Answer
Hach offers several turbidimeters and each instrument line has two version of that instrument. The options are an EPA version and an ISO version. The major difference is in what light source is used. EPA versions usually use a white light source from a tungsten filament, while the ISO versions use an LED at a specific wavelength. Respectively, they are required in order to meet EPA and ISO requirements. As turbidity units are defined by the light source used, EPA and ISO turbidimeters report results in different units.

When the samples are colored the light source used becomes very important. When using an EPA version of a turbidimeter some of white light will be absorbed by the color of the sample. Therefore, the results are going to be higher with an ISO turbidimeter relative to an EPA than they otherwise would be on noncolored samples in which results would be much closer. The wavelength that is used for the ISO versions is 860 nm which is outside the visible spectrum and, therefore, results are uninfluenced by sample color.

So if the sample is colored, EPA requirements do not need to be met, and results of FNU are acceptable, it would be recommended to get the ISO version of the turbidimeter.
Here is a list of currently available ISO turbidimeters:
2100Qis (Product # 2100QIS01) - This is the portable option.
TL2310 (Product # LPV444.99.00120) - Benchtop with 0-1000 FNU range
TL2360 (Product # LPV444.99.00320) - Benchtop with 0-10,000 FNU range
TU5200 ISO (Product # LPV442.99.01022) - Benchtop laser turbidimeter with 0-1000 FNU range (preferred for samples below 10 FNU)

Was this answer helpful?

Submitting...
Thank you for your feedback!
There was an error with your submission. Please try again.