PASCO Specialty & Mfg. PS-2126A User's Manual
Contents
1. com 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 O 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 O 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 O 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 packa2. 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 dur ing typical operating conditions Warning Do not allow the sensing element to contact liquids TEIH Collecting O Samples 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 O 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
3. 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 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
4. with the membrane for extended periods of storage Sensor life may be extended by storing the sensing element in a refrigerator at 40 F to 50 F 4 C to 10 C Do not freeze the sensor or sensing element TEIH Specifications Range 0 to 100 O concentration O to 1000000 parts per million ppm Resolution 0 025 oxygen Repeatability 0 5 oxygen Accuracy 1 O at constant temperature and pressure 5 Os over operating temperature range Operating temperature 0 to 40 C Relative humidity range 0 to 100 non condensing Sensing element 4 years useful life Sensing element 24 months warranty period Technical Support For assistance with any PASCO product contact PASCO at Address PASCO scientific 10101 Foothills Blvd Roseville CA 95747 7100 Phone 916 786 3800 worldwide 800 772 8700 U S Fax 916 786 3292 Web WWw pasco com Email support pasco com Limited Warranty For a description of the product warranty see the PASCO catalog Copyright The PASCO scientific 012 11736B Oxygen Gas Sensor Instruc tion 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 class rooms and are not sold for profit Reproduction under any other circum stances without the written consent of PASCO scie
5. ging 2 Remove the pink tape from the Oxygen Sensing Element 3 Carefully thread the deflector onto the Oxygen Sensing Element 4 Slide the rubber stopper over the deflector Model No PS 2126A 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 O 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 element inside a plastic bag Press any atmo a spheric 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 h Y et 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
6. ntific is prohibited Trademarks PASCO PASCO scientific DataStudio PASPORT Xplorer Xplorer GLX SPARK and SPARKvue are trademarks or registered trade marks of PASCO scientific in the United States and or in other countries For more information visit www pasco com legal
7. pasforl Instruction Sheet 012 11736B Oxygen Gas Sensor PS 2126A sensor amplifier sensing rubber stopper element ll A i i ey i N W i y sampling connecting cable bottle Included Equipment Part Number PS 2126A includes sensing element Sensor Amplifier Oxygen Sensing Element with deflector 699 299 Rubber Stopper 699 08186 Connecting Cable 3 5 millimeter 514 08583 Sampling Bottle 650 064 Required Equipment PASPORT Interface See PASCO catalog or Www pasco com 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 O gt 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 f B A Toy os o 800 772 8700 www pasco
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