PASCO PASPort PS-2126A User manual

Instruction Sheet
012-11736E
Oxygen Gas Sensor
PS-2126A
Introduction
The PS-2126A Oxygen Gas Sensor measures oxygen gas con-
centration in percent (%) and parts per million (ppm) oxygen.
It can be used to study plant, animal, or cellular respiration; air
quality; and the rate of oxygen (O2) production in chemical
reactions (see the experiment on page 2 for one example).
How it works:
The Oxygen Sensing Element is a galvanic fuel cell with a gas
permeable membrane at one end. It is very similar to a battery.
The fuel cell contains an electrolyte, anode and cathode. When
oxygen enters the fuel cell through the membrane, a chemical
reaction between the metallic cathode and anode and the elec-
trolyte occurs. This chemical reaction produces a voltage and
current that is present at the output jack at the other end of the
Oxygen Sensing Element. The current produced is propor-
tional to the concentration of oxygen present.
Oxygen Sensing Element Life:
Galvanic fuel cells have a limited lifetime which is determined
by their age and their exposure to oxygen. This is similar to
the life of a battery in a flashlight. If the flashlight frequently
used, the battery life will not be as long as it would have been
with limited usage. Similarly, the fuel cell’s useful life is
determined by its exposure to oxygen gas.
The fuel cell included with the PS-2126A has a useful life of
900,000 oxygen percent (O2 %) hours.
An example: If the sensor is used in a 100% oxygen atmo-
sphere, the life of the sensor may be calculated as
900,000 O2 % hours divided by 100% oxygen which is
9,000 hours. This is about 1 year.
The life of the sensor in normal air (20.9% oxygen) is
900,000 O2 % hours divided by 20.9% oxygen which is
43,062 hours. This is about 4.9 years.
The sensor is guaranteed for a minimum of 2 years from the
date of manufacture. This is the absolute guarantee. If it is
used in a 100% oxygen atmosphere its life will be shortened.
If it is used in normal air, its life will be 4 to 5 years. There is
reported evidence of this particular sensing element being in
use for almost 10 years. In the end, the useful life of the sens-
ing element is dependent on the manner in which it is used.
Setup
Connect the Oxygen Gas Sensor to your PASPORT interface.
To prepare the Oxygen Sensing Element for use:
1. Remove the Oxygen Sensing Element and deflector from
the packaging.
2. Remove the pink tape from the Oxygen Sensing Element.
sensor amplifier
sampling
bottle*
connecting cable
sensing
element
rubber stopper
Included Equipment Part Number
Sensor Amplifier PS-2126A (with
sensing element)
Oxygen Sensing Element (with deflector) PS-6524
Rubber Stopper
Connecting Cable (3.5 millimeter)
Sampling Bottle*
Required Equipment
PASPORT Interface and Software See PASCO catalog
or www.pasco.com
*CAUTION: Do not wash
the sampling bottle in a
dishwasher or autoclave.
It will melt.

Model No. PS-2126A Collecting O2 Samples
2
012-11736E
3. Carefully thread the deflector onto the Oxygen Sensing
Element.
4. Slide the rubber stopper over the deflector.
5. Plug one end of the connecting cable into the Oxygen
Sensing Element.
6. Plug the other end of the connecting cable into the Sensor
Amplifier.
7. Connect the Sensor Amplifier to the PASCO interface.
8. Refer to the documentation that came with the PASCO
interface and software for further instructions for data
collection.
Collecting O2 Samples
To collect an atmospheric sample,
hold the bottle upright and open
to the air. Insert the end of the
sensing element into the bottle.
Press the rubber stopper into the
neck to seal the bottle.
To collect expired air or other gas
samples, place the sensing ele-
ment inside a plastic bag. Press
any atmospheric air out of the bag. Use a tube to fill the bag
with the gas sample. Hold, tie, or clamp the bag closed round
the tube and sensing element cable to contain the gas sample
and exclude atmospheric air.
When doing an experiment that requires a faster than usual
response time, the response time of the sensor may be
increased by removing the white deflector and stopper from
the Oxygen Sensing Element. This shortens the path to the
sensor's membrane allowing it to be populated more rapidly
with the sample.
The purpose of the white deflector is to deflect air from an air
stream into the sensing element and provide protection for the
gas permeable membrane. It also holds the rubber stopper.
While the white deflector is removed from the sensing ele-
ment, be careful not to place sharp objects near the membrane
as puncturing the membrane could lead to damage to the sens-
ing element and electrolyte leaking from the membrane.
Removal of the deflector is not required or recommended
during typical operating conditions.
Warning: Do not allow the sensing element to contact liquids. Caution:
Do not clean the sampling bottle in a dishwasher or autoclave.
Calibration
The sensor is factory calibrated. However, for greater accu-
racy, you can follow these steps to calibrate the sensor:
1. With the sensor connected to a powered PASPORT inter-
face, place the sensing element in the empty sampling
bottle. Outside air has an O2 concentration 20.9%.
2. Press the CAL (20.9%) button on the sensor and hold it
for 3 seconds. The green light will flash on and off for 4
seconds, indicating that calibration is in progress.
3. After 4 seconds, the reading will stabilize at 20.9%. When
calibration is complete, the light will stop flashing.
Note: If the green light flashes rapidly after calibration, the sensing ele-
ment may be expired and it may need replacement.
Experiment: Oxygen
Production from Liver Catalase
Equipment required: Oxygen Gas Sensor with sampling bottle, beef
or chicken liver, hydrogen peroxide, pipette, mortar and pestle, ice
bath, boiling water, and safety goggles.
Safety: Always wear safety goggles when performing this experiment.
Do not allow excessive pressure to develop in the sampling bottle.
1. Place the liver in an open container and allow it to warm
to room temperature.
2. (Optional) Calibrate the Oxygen Gas Sensor (see above).
3. Grind the liver to a mushy consistency.
4. Place 10 mL of hydrogen peroxide into the clean, dry
sampling bottle.
Note: Perform step 5 through 7 carefully and quickly.
5. With a pipette, extract 1 mL of blood/homogenate from
the ground liver and release it into the sampling bottle.
6. Insert the end of the sensing element into the bottle. Press
the rubber stopper into the neck of the bottle just enough
to close the bottle, but not too tightly
7. Start data collection on the computer or interface.
8. After about 300 seconds, stop data collection.
9. Clean and dry the sampling bottle. Repeat steps 4 through
8 with cold liver homogenate that has been chilled in an
ice bath. Repeat again with liver homogenate that has
been boiled in water.
10. Compare your results from the three runs.

Model No. PS-2126A
3
012-11736E
Sensing Element Maintenance
Storage:
The Oxygen Sensing Element may be stored in its package
until its first use.
It is recommended that the sensing element be stored with the
threaded nose piece in the downward position. This insures
that the electrolyte remains in contact with the membrane for
extended periods of storage. Sensor life may be extended by
storing the sensing element in a refrigerator at 40ºF to 50ºF
(4°C to 10°C). Do not freeze the sensor or sensing element.
Replacement:
Order Model Number PS-6524 Oxygen Sensing Element
Replacement.
Specifications
Technical Support
For assistance with any PASCO product, contact PASCO at:
To see the latest revision of this instruction sheet, visit the
PASCO Web site at www.pasco.com/manuals and enter the
Product Number (for example, PS-2126A).
Limited Warranty: For a description of the product warranty, see the
PASCO catalog.
Copyright: This PASCO scientific Instruction Sheet is copyrighted with all
rights reserved. Permission is granted to non-profit educational institutions
for reproduction of any part of this manual, providing the reproductions are
used only in their laboratories and classrooms, and are not sold for profit.
Reproduction under any other circumstances, without the written consent of
PASCO scientific, is prohibited.
Trademarks: PASCO and PASCO scientific are trademarks or registered
trademarks of PASCO scientific, in the United States and/or in other coun-
tries. For more information visit www.pasco.com/legal.
Product End of Life Disposal Instructions:
This electronic product is subject to disposal and recycling regu-
lations that vary by country and region. It is your responsibility to
recycle your electronic equipment per your local environmental
laws and regulations to ensure that it will be recycled in a manner
that protects human health and the environment. To find out
where you can drop off your waste equipment for recycling,
please contact your local waste recycle/disposal service, or the
place where you purchased the product.
The European Union WEEE (Waste Electronic
and Electrical Equipment) symbol (to the right)
and on the product or its packaging indicates
that this product must not be disposed of in a
standard waste container.
Range 0 to 100% O2 concentration
0 to 1000000 parts per million (ppm)
Resolution 0.025% oxygen
Repeatability ±0.5% oxygen
Accuracy ±1% O2 at constant temperature and
pressure; ±5% O2 over operating
temperature range
Operating temperature 0 to 40 °C
Relative humidity range 0 to 100%, non-condensing
Sensing element
useful life
4+ years
Sensing element
warranty period
24 months
Address: PASCO scientific
10101 Foothills Blvd.
Roseville, CA 95747-7100
Phone: [phone] (worldwide)
800-786-3800 (U.S.)
Web: www.pasco.com
Email: [email protected]