Hach-Lange 2100P iso - Portable Turbidimeter Instrument - Manual (Page 25)

Page 25
4650098 measure.fm TURBIDITY MEASURE
Section 3 TURBIDITY MEASURE
3.1 Turbidity Measurement
Measurements may be made with the signal average mode on or off and in manual
or automatic range selection mode.
With signal average mode off, the final value is displayed after approximately 12
seconds.
Accurate turbidity measurement depends on good measurement technique by the
analyst, such as using clean sample cells in good condition and removing air
bubbles (degassing).
3.1.1 Turbidity Measurement Procedure
1. Thoroughly clean
the sample cell.
2. Collect a
representative sample
in a clean container.
Fill a sample cell to the
line (about 15 mL),
taking care to handle
the sample cell by the
top. Cap the cell.
3. Wipe the cell with a
soft, lint-free cloth to
remove water spots and
fingerprints.
4. Apply a thin film of
silicone oil. Wipe with
a soft, lint-free cloth to
obtain an even film
over the entire surface.
Note: Applying a thin coat
of silicone oil will mask
minor imperfections and
scratches which may
contribute to turbidity or
stray light. Use silicone oil
equivalent to Hach Cat. No.
1269-36, which has the
same refractive index as
glass.