PASCO PS-2122 Turbidity Sensor - Manual (Page 3)

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M o d e l N o . P S - 2 1 2 2 P r o d u c t D e s c r i p t i o n
3
Preparation Procedures: Intermittent Use
If the 100 NTU Standard cuvette has been stored for more
than one month, do the following before calibration:
1. Shake the cuvette vigorously for one minute to stir up
the particles.
2. Allow the cuvette to stand undisturbed for five minutes
to eliminate air bubbles.
3. Gently invert the cuvette five times.
4. Clean the outside of the glass cuvette.
Expiration
By following the preparation procedures, the 100 NTU
Standard sample should provide accurate results (±7%) up
to the expiration data on the bottom of the cuvette. After
the expiration date, PASCO cannot guarantee the stability
of the sample. Order PS-2511 to replace the 100 NTU
Standard sample.
Sensor Usage Tips
• For very turbid samples, the initial turbidity measure-
ment will fluctuate as particles begin to settle. Wait for
the reading to stabilize and then record the measure-
ment.
• Avoid taking readings around bright lights. Make sure
that the lid is closed securely.
• Avoid or dilute dark-colored samples.
• Always fill the cuvette to the lid with at least 6 mL of
sample.
• Before making a turbidity reading, use a sieve or pipette
to remove “floaters” or large, visible particles of sedi-
ment from the sample
Orienting the Cuvette (Optional)
To minimize variations in the readings due to natural dif-
ferences or imperfections in the glass of the cuvette, do the
following for each cuvette you plan to use:
1. Insert the cuvette containing 6 mL of a sample into the
Sample Compartment, but do not close the lid. Instead,
grasp the cap of the cuvette.
2. Put a piece of black cloth over your hand and the sensor
so that no light enters the sensor.
3. Set up a Digits display in the data acquisition software.
Start recording data.
4. With your covered hand, rotate the cuvette while
observing the reading in the display. At the lowest tur-
bidity reading, stop recording data. Do not rotate the
cuvette any further. Stop recording data.
5. With the cuvette still in the Sample Compartment, place
one of the provided arrow labels on the cap, with the
arrow pointing toward the screw on the front of the
Sample Compartment.
For subsequent measurements, always align the arrow
with the screw. Do not switch caps between cuvettes.
Specifications
*1 NTU = one nephelometric turbidity unit
Other Items
*Use the Silicon Oil to wipe the outside of the glass cuvette.
Item Information
Range: 0 to 400 NTU*
Accuracy: ± 0.2 NTU for 0 to 20 NTU
± 0.5 NTU for 20 to 100 NTU
±1 NTU for 100 to 400 NTU
Resolution: 0.1 NTU
Temperature Range: 5 to 40 °C
Cuvettes and Caps PS-2509 (set of 6 each)
Silicone Oil* PS-2510
Sample Compartment
Lid
Cap Label
with Arrow
Screw