Thermo Fisher Scientific C101 Colorimeter - Manual (Page 12)

Measurement
C401/301/201/101/102/103/104/105 Colorimeter
8
4. Turn on the meter by pressing the ON/OFF key.
5. For the single-parameter colorimeter, the display will momentarily
show the test to be performed before switching directly to [STbY] as
that of step 6. For the multi-parameter colorimeter, the display will
indicate the last test performed. Press the MODE key to make
selection on the desired test to be performed.
6. Press the READ/ENTER key to confirm your selection. The meter will
display [STbY] indicating it is ready to accept a measurement or a
blanking.
7. Press the ZERO key to perform the blanking of the meter. If the user
chooses to skip this step, the meter will use the last value of the
blank for the next calculation.
8. Remove the sample vial used for blanking from the instrument and
add the appropriate reagent to it. Cap the vial and follow the
appropriate instructions (including the time required to develop the
color) for each type of reagents.
9. Place the vial with the developed color into the sample well and align
the ▼ mark on the vial with the ▲ mark on the instrument, and press
it down until it snaps fully into the optical holder.
10. Press the READ/ENTER key. The meter will display the reading in
appropriate units within 3 seconds.
11. To repeat the measurement of the same sample, repeat steps 7-11.
Ideally, step 7 should not be skipped, but the user may do so if
testing the same sample.