Measurement Of High Turbidity Values - Lovibond TB 300 IR Mode D'emploi

Type of Method
sample
Samples that Addition of a surf-
are oversatu- actant
rated with air
Liquid samp- Use of a partial
les without vacuum
readily volatile
components
Viscous Use of an ultrasonic
samples bath
Very viscous Heating the sample
samples

2.3.8.2 Measurement of high turbidity values

High turbidity samples with more than 1100 NTU ("overrange") may be diluted. The dilution
water should be a water with very low turbidity as described in chapter 2.3.7.1 "Preparing
dilution water".
For accurate dilution proceed as follows:
Mix the water sample well and pipette x ml of the water sample (see table below) into
a 100 ml volumetric flask. Fill with low turbidity water up to the mark and mix gently.
Water sample
(x ml)
10
25
50
Fill the diluted water sample into the vial, perform reading and multiply the displayed result
with the multiplication factor.
TB300 IR 6 03/2022
Description of the
method
Surfactants minimise
the surface tension
of a sample, allowing
entrained gases to
disappear.
A vacuum can be crea-
ted with the help of a
clean, oil-free syringe
or pump fitted onto
a vial.
The vacuum reduces
the atmospheric pres-
sure, so that trapped
air bubbles can be
removed.
The ultrasonic waves
excite the sample,
effectively removing
air bubbles from most
samples.
Heating the sample
makes it less viscous,
air bubbles can disap-
pear more easily.
The sample has to cool
to its original tempe-
rature.
Multiplication factor
10
4
2
Notes:
Particles in the sample
settle more rapidly, so
the sample must be
swirled before being
measured. Avoid vi-
gorous shaking as this
causes the surfactant
to foam.
Volatile components
can escape from the
sample.
The vacuum may com-
pound the air bubble
problem in viscous
samples.
Ultrasonic waves can
change the particle
size in the sample,
therefore changing the
turbidity.
Volatile components
can disappear from the
sample. The attributes
of suspended particles
change, therefore
changing the turbidity.
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