Hach-Lange 2100 AN Laboratory Turbidimeter User Manual - Manual (Page 28)

Measurement
• Measure samples immediately to prevent temperature changes and
settling. Before a measurement is taken, always make sure that the
sample is homogeneous throughout.
• Avoid sample dilution when possible.
• Avoid instrument operation in direct sunlight.
Turbidity measurement procedure
1. Rinse a clean,
empty sample cell two
times with the solution
to be measured and
drain to waste. Fill to
the line (about 30 mL)
with sample and
immediately put the cap
on the sample cell. 2. Clean the sample
cells with a soft, lint-free
cloth to remove water
spots and fingerprints. 3. Apply a small bead
of silicone oil from the
top to the bottom of the
sample cells. 4. Use the oiling cloth
provided to apply the oil
equally to the surface of
the sample cells.
Remove the excess oil.
Make sure that the
sample cells are almost
dry. 5. Gently and slowly
invert the sample cell to
fully mix the sample. Be
careful not to add air
bubbles. 6. Put the sample cell
in the sample cell
holder with the triangle
on the sample cell
aligned with the
reference mark on the
sample cell holder.
Close the cover.
26 English