Specifications
About Turbidity Measurement
What is Turbidity?
Turbidity refers to the concentration of undissolved, suspended particles
present in a liquid measured in Nephelometric Turbidity Units (NTU). It
is important to note that turbidity is a measure of sample clarity and
not colour.
Water with cloudy or opaque appearance will have high turbidity, while
water that is clear or translucent will have low turbidity. High turbidity
value is caused by particles such as silt, clay, microorganisms, and organic
matter. By denition, turbidity is not a direct measure of these particles
but rather a measure of how these particles scatter light.
Why is Turbidity Important?
This determination of clarity in water is important in many manufacturing
operations such as beverage production, food processing and potable
water treatment plants.
For drinking water application, a turbidity value may give an indication
of presence of bacteria, pathogens, or particles that can shelter harmful
organisms from disinfection process. Therefore, turbidity measurement is
particularly useful for water treatment plants to ensure cleanliness.
In industrial processes, turbidity can be part of quality control to verify
the eciency in treatment or manufacturing process.
Good Measurement Techniques
Turbidity is a very complex analytical measurement which can be aected
by many factors. Some are inherent in the instrument’s design such as
angle of detection, light beam aperture, incident beam wavelength and
colour sensitivity of the photocell.
However, there are other factors such as stray light, air bubbles and
care of vial, which can be prevented through proper care of equipment
and accessories.
The Eutech CyberScan TB 1000 turbidimeter meets the performance
criteria specied by US EPA method 180.1 for NTU measurement.
In addition, the infrared light source models meet the ISO 7027
standards of measurement. The Eutech waterproof handheld
TN 100 turbidimeter designed for testing on-the-go features
laboratory accuracy and excellent repeatability with US EPA
approved non-formazin standards and is ISO 7027 compliant.
Maintain Sample Vials in Good Condition
Sample vials must be meticulously clean and free from significant
scratches. It should be treated on the outside with a thin coat of silicone
oil. This is to mask minor imperfections and scratches that may contribute
to stray light. Sample vials should be handled only by the top to avoid
dirt accumulation (or deposits) and ngerprints that might interfere
with the light path.
Match Sample Vials
Best accuracy and repeatability of turbidity measurement are achieved
using a single, indexed vial. However, for more convenience, dierent
vials can be used for measurement provided their readings with the same
solution are matched. That is, the meter gives identical readings or within
the specied repeatability and accuracy of the meter.
Timeliness of Sample
Samples should be measured immediately to prevent changes in
particle characteristics due to temperature and settling. Temperature
can aect particles by changing their behavior or creating new particles
if precipitates form. Dilution water may dissolve particles or change
their characteristics. It is recommended to take samples only when the
turbidimeter is ready to be operated. Samples should not be drawn and
allowed to sit while the instrument warms up.
Other Important Sampling Techniques
1. Samples should not be violently shaken or agitated as particles
can be broken apart or air may be entrapped into the uid.
Gentle agitation such as swirling the sample vial is advisable to
reduce particle settling.
2. Sample vials should be used only with the instruments for which
they are intended. Do not mix and match.
3. Perform a visual observation of the sample vial every time a
measurement is made. Ensure that there are no visible bubbles in
the sample and the vial is clean and free of scratches.
4. Samples placed in the turbidimeter should be at the same
temperature as the process ow samples. Changes in temperature
can cause precipitation of soluble compounds and aect readings.
5. Sample vials should be evaluated with a low turbidity water
(after cleaning) to determine if vials remain matched. If the
evaluation determines that a vial is corrupted, discard the vial.
It is recommended to conduct this evaluation weekly.
6. When in doubt or question about whether a sample vial is too
scratched or stained, throw it away.
The Eutech CyberScan deluxe bench meter TB 1000 allows
instantaneous sampling without having to transfer samples into
vials hence providing hassle-free laboratory research.
Turbidity | About Turbidity Measurement
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