Hach-Lange 2100 AN Laboratory Turbidimeter User Manual - Manual (Page 30)

Absorbance and transmittance measurement procedure
Note: To measure samples with negative absorbance, set the analytical zero using the sample with the greatest absorbance, and measure the sample with the least
absorbance. Report the reading as negative absorbance.
1. Put a clean filter
assembly in the
instrument. Refer to
Change the filter
assembly
on page 48.
Note: The minimum
wavelength for
absorbance and
transmittance
measurement is
420 nm.
2. Push UNITS/Exit
until "%T" or "ABS" is
shown on the display. 3. Using the manual
flow cell kit, install the
flow cell. Refer to
Using
a flow cell
on page 33.
Note: The sample cell
cover does not close
when the flow cell is
installed.
4. Slowly put 250 mL of
100 %T or zero
absorbance reference
solution down the
interior edge of the inlet
reservoir.
Put the sample down
the interior edge of the
reservoir to prevent air
bubbles in the sample. 5. Push CAL/Zero.
The display shows
"100 %T" or zero.
Note:
The instrument starts
analytical zeroing for
color, transmittance,
and absorbance modes
at the same time. 6. Push ENTER.
The instrument display
counts down from 30 to
0.
Note: If the value
shown is not 100 %T,
0.000 A, or if dashes
flash, do steps 5 and
6 again.
28 English