Absorbance and transmittance measurement, Measurement notes, Absorbance and transmittance measurement procedure – Hach-Lange 2100 AN IS Laboratory Turbidimeter User Manual User Manual
Page 29
Absorbance and transmittance measurement
Measurement notes
For the best accuracy and reproducibility:
• Absorbance and transmittance can only be measured at 860 nm.
• Set the zero reference point before measurement. Set the zero
reference point again when a measurement is not taken for several
hours as shown in
Absorbance and transmittance measurement
on page 27.
• Transmittance and absorbance measurements use the same zero
reference point. Absorbance and transmittance can be measured on a
single sample after setting a zero reference point in one of the two
modes.
• Use a flow cell for measurements. A flow cell is necessary to get the
accuracy and reproducibilty specifications shown in
on page 5.
If a flow cell is not used, use a single indexed sample cell or match
sample cells. Sample cells should be matched using the
Transmittance or Absorbance modes. Refer to
on page 21.
• Refer to
on page 25 for more measurement
notes.
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. Push UNITS/Exit
until "%T" or "ABS" is
shown on the display.
2. Using the manual
flow cell kit, install the
flow cell. Refer to
on page 30.
Note: The sample cell
cover does not close
when the flow cell is
installed.
3. 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.
4. Push CAL/Zero.
The display shows
"100 %T" or zero.
Note:
The instrument starts
analytical zeroing for
transmittance, and
absorbance modes at
the same time.
5. 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.
6. Slowly put 250 mL of
the sample in the inlet
reservoir.
English 27