What is Turbidity?
Turbidity is a measure of sample clarity. The term is used to describe the cloudy or milky appearance of a liquid.
Turbidity is due to particles of varying sizes scattering or absorbing light, giving the medium in question a cloudy appearance. High turbidity value is caused by particles such as silt, clay and micro-organisms. It is not a direct measure of these particles but rather a measure of how these particles scatter light. Turbidity is measured in Nephelometric Turbidity Units (NTU).
Measurement of Turbidity is important in many manufacturing operations such as beverage production, food processing and potable water treatment plants. For drinking water, a turbidity value may give an indication of bacteria, pathogens or particles that can shelter harmful organisms from the disinfection process. In industrial processes, turbidity can be part of quality control to verify the efficiency in treatment or production processes.
Tips for accurate measurement:
- Most important: DO NOT SHAKE sample vials (or calibration standards) before testing, this can cause bubbles.
- Rather invert (turn upside down) twice before reading the results, don’t let the contents settle.
- Samples should be measured immediately to prevent changes due to temperature or settling.
- The vial must be very clean. Don’t use silicone / oil , use a tissue / contact lens tissue to remove fingerprints or dust.
- If there are any scratches or stains on the vials, have them replaced.