Hach-Lange 2100 AN Laboratory Turbidimeter Basic User Manual - Manual (Page 14)

• Keep the sample compartment lid closed to keep dust and dirt out.
Sample cells
• Always cap the sample cell to prevent spillage of the sample into the
instrument.
• Always use clean sample cells in good condition. Dirty, scratched or
damaged cells can result in readings that are not accurate.
• Make sure that cold samples do not “fog” the sample cell.
• Store sample cells filled with distilled or deionized water and cap
tightly.
• For the best accuracy, use a single sample cell for every
measurement or a flow cell.
Note: As an alternative, matched sample cells may be used for measurements but
do not provide as good of accuracy or precision as a single indexed sample cell or
flow cell. When using matched sample cells, align the orientation mark on the
sample cell with the reference mark on the sample cell holder.
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.
14 English