Instruction Manual Manual No. 012-07688E PASPort Dissolved Oxygen Sensor Model No.
Instruction Manual Manual No. 012-07688E PASPort Dissolved Oxygen Sensor Model No.
Model No. PS-2108 Dissolved Oxygen Sensor Table of Contents Equipment List .......................................................... 1 Introduction ............................................................. 1 DO Sensor Setup and Calibration...................................... 3 Prepare the Sensor for First Use .................................................................................................... 3 Set up the Dissolved Oxygen Sensor with DataStudio.......................................
Model No. PS-2108 Dissolved Oxygen Sensor Experiment 3: Effect of Sodium Sulfite on Dissolved O2 Concentrations ......... 20 Materials and Equipment Needed................................................................................................ 20 Optional Materials ....................................................................................................................... 20 Purpose..........................................................................................................
Model No. PS-2108 Dissolved Oxygen Sensor PASPort Dissolved Oxygen Sensor Model No. PS-2108 Equipment List Included Equipment 1. Dissolved Oxygen Probe (1) Replacement Model Number* 699-06320 2. PASPORT Dissolved Oxygen Sensor box (1) 3. Membrane Replacement Kit (1) CI-6541 4. Soaker Bottle (1) 5. Electrolyte Solution (1) R001068 6. Syringe for filling cartridge housing (1) *Use Replacement Model Numbers to expedite replacement orders.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 The sensor functions by measuring the electric current produced by a chemical reaction in the probe. The chemical reaction involves the reduction of oxygen (O2) molecules and the oxidation of the silver (Ag) atoms of the anode. A voltage of 0.7 volts is applied across the electrodes, causing the desired redox reaction (see below) to be favored.
Model No. PS-2108 Dissolved Oxygen Sensor The negatively charged hydroxide ions diffuse to the silver anode. There they combine with silver (Ag) atoms from the silver anode, forming silver oxide and releasing electrons that join the current in the electrode in the following chemical reaction: - 4Ag + 4OH 2Ag 2 O + 2H 2 O + 4e - Reduction potential = 0.343V The released electrons produce a current that passes from the electrode and is amplified.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 Equilibrate the Probe in 100% Humidified Air 1. Place about 5 mL (to a height of about 1 cm) of deionized water into a clean soaker bottle. Slip the cap and O-ring of the soaker bottle over the end of the probe. 2. Insert the probe into the soaker bottle and screw on the lid. Adjust the height of the end of the probe to about 2 cm above the top of the water (Figure 4). 3. Shake the soaker bottle vigorously for about 10 seconds.
Model No. PS-2108 Dissolved Oxygen Sensor your software settings back to mg/L. DataStudio: Click the Setup button on the DataStudio toolbar. Click the % button next to the Calibrate button and select mg/L from the drop-down menu. Note: Calibration is not required for measurements of relative DO content, such as before/during/after experiment relative changes. 2. Click the Calibrate… button to open the Calibrate dialog. 3. Place the probe in 100% humidified air.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 General Sampling Procedure 1. Immerse the Dissolved Oxygen probe into the test solution until the silver temperature compensation band is submerged. 2. Click the Start button on the DataStudio tool bar or select Monitor Data from the Experiment menu. 3. Gently, swirl the probe for a minute or two until the dissolved oxygen readings stabilize around a value.
Model No. PS-2108 Dissolved Oxygen Sensor Maintenance Changing the Electrolyte solution The electrolyte solution (probe filling solution) should be periodically replaced and the silver electrode cleaned to maintain optimal performance of the probe. If the probe is not performing optimally, replace the electrolyte solution as follows: 1. Unscrew the end of the probe by turning it to the left, and remove the cartridge housing (Figure 5).
PASPort Dissolved Oxygen Sensor Model No. PS-2108 2. Use the supplied plunger to push the membrane cartridge out of the cartridge housing (Figure 7A). B A 3. Examine the O-ring (Figure 8) and replace it if it is damaged (See "Replacing the O-ring" below.). 4. Insert a replacement membrane cartridge and use the plunger to push it down until it is seated at the end of the housing that has the O-ring (Figure 7B). 5.
Model No. PS-2108 Dissolved Oxygen Sensor Storage Short-Term Storage (two weeks or less) Store the probe in the plastic storage bag with the tip inserted in the soaker bottle containing about 10 ml of deionized water. Long-Term Storage (more than two weeks) 1. Unscrew and remove the cartridge housing by turning it to the left. Always hold the probe below the stainless steel band when unscrewing the cartridge housing or otherwise applying torque to the end of the probe. 2.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 Theory of Dissolved Oxygen: What is the chemical mechanism by which diatomic oxygen dissolves in water? This is a particularly eloquent description of the mechanism of oxygen solubility in water: [from Water on the Web1] Water, as a polar molecule, induces an accumulation of electron density (dipole moment) at one end of nonpolar gas molecules such as oxygen (O2) and carbon dioxide (CO2).
Model No. PS-2108 Dissolved Oxygen Sensor 1. Water Temperature effects • Gases usually dissolve in liquids in an exothermic process.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 2. Overlying Gas Pressure Effects • Henry's Law states that the solubility of a gas in a liquid is affected by the pressure of the gas above the liquid-gas interface.
Model No. PS-2108 Dissolved Oxygen Sensor equilibrium. A famous, naturally occurring case of supersaturation and subsequent gas release (in this case it was dissolved carbon dioxide gas) was the Lake Nyos tragedy, which took place in Cameroon (1986). 4. Salinity. • Salt and other solids dissolved in water will affect the total amount of gas that a liquid solvent can dissolve. Given otherwise identical conditions, fresh water can hold more dissolved oxygen than salt water.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 Chlorinity (freshwater) Temp. (°C) 0 g/L Cl- 5.0 g/L Cl- 10.0 g/L Cl- 15.0 g/L Cl- 20.0 g/L Cl- 25.0 g/L Cl- 15.0 10.084 9.541 9.027 8.540 8.079 7.642 16.0 9.870 9.344 8.844 8.370 7.922 7.496 17.0 9.665 9.153 8.667 8.207 7.770 7.356 5.
Model No. PS-2108 Dissolved Oxygen Sensor Experiment 1: Introduction to the Operation of the Dissolved O 2 Sensor Purpose The purpose of the experiment is to explore the basic operation of the Dissolved Oxygen Sensor: how to set it up, how to calibrate it, and how to obtain the most accurate measurements with it.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 6. Click the Start button on the DataStudio toolbar to begin recording data (Data Run #2). 7. Allow the probe to rest undisturbed in the test solution and observe the sensor reading. 8. After the sensor reading stabilizes at the new level, gently move the probe back and forth through the test solution and observe the sensor reading. 9. After the sensor reading stabilizes at the new level, repeat steps 6 and 7 several times. 10. .
Model No. PS-2108 Dissolved Oxygen Sensor Experiment 2: Photosynthesis and Oxygen Generation with Aquatic Plants Purpose Explore the change in level of dissolved oxygen in water associated with photosynthesis of aquatic plants.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 Procedure 1. Perform a test run on the DO sensor(s) to ensure that the membrane is intact. 2. Arrange equipment so that the two large test tubes are nearly full of water. 3. Clamp test tubes in place vertically, with the beaker as a water bath (to minimize temperature fluctuations). 4. With no plants in place, allow the entire system to reach equilibrium for about three to four hours (it is not harmful to exceed this time).
Model No. PS-2108 Dissolved Oxygen Sensor Collecting Data 8. Begin collecting data. Allow the system to take in ambient light for 60 seconds, and then cover the entire set up with an opaque cloth, such as a rubberized lab apron. After fifteen minutes, remove the cover and turn on the light. Continue to collect data for another fifteen minutes. Stop data collection. 9. If desired, conduct additional data runs in a similar manner. Sample Data Analysis 1.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 Experiment 3: Effect of Sodium Sulfite on Dissolved O 2 Concentrations Materials and Equipment Needed • • • • • • • • Dissolved Oxygen Sensor PASPort interface or logger 2 M sodium sulfite (25.2 g Na2SO3/100 ml) aquarium pump or large bottle PASPort USB Interface and DataStudio software 600 ml beaker 400 ml deionized water pipet Optional Materials • hot plate/stir plate and magnetic stir bar CAUTION: Sodium sulfite is a potential skin irritant.
Model No. PS-2108 Dissolved Oxygen Sensor Questions 1. Describe the effect of sodium sulfite on dissolved O2 concentrations. 2. Discuss some potential environmental effects of untreated effluent from industries or businesses such as paper mills and photo labs that may use sodium sulfite.
PASPort Dissolved Oxygen Sensor Experiment 4: Biochemical Oxygen Demand Model No. PS-2108 1 Background Biochemical oxygen demand (BOD) is an important measure of water quality. BOD is a measurement of the quantity of oxygen used by microorganisms in the aerobic oxidation of organic matter. In rivers and streams with high BOD levels, much of the available dissolved oxygen is consumed by aerobic bacteria, robbing other aquatic organisms of the oxygen they need to live.
Model No. PS-2108 Dissolved Oxygen Sensor Experiment 5: The Effect Of Respiration On Dissolved O 2 Concentration Purpose The purpose of the experiment is to explore the effect of respiration on dissolved O2 concentrations.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 8. Stop recording and save the data. Questions 1. What is the evidence that the yeast cells are alive and respiring during the experiment? 2. What happens to the yeast cells when the dissolved O2 concentration reaches zero? (Hint: Look carefully at the beaker that contains the concentrated yeast solution and think about how yeast is used in industry.
Model No. PS-2108 Dissolved Oxygen Sensor Appendix A: Copyright and Warranty Information Copyright Notice The PASCO scientific 012-07688D manual is copyrighted and all rights are reserved. However, permission is granted to non-profit educational institutions for reproduction of any part of the Dissolved Oxygen Sensor manual providing the reproductions are used only for their laboratories and are not sold for profit.
PASPort Dissolved Oxygen Sensor Model No.
Model No. PS-2108 Dissolved Oxygen Sensor Appendix C: Tables Table 1: Concentration of dissolved oxygen (mg/L) in water at various temperatures and pressures From R. F. Weiss (1970). Temp ° C, temperature in degrees Celsius; atmospheric pressures from 695-600 millimeters mercury (27.36-23.62 “Hg) begin after 40° C Conversion Factors: 1.0 “Hg = 25.4 mmHg = 33.86 mb or hPa Temp.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 Temp. Atmospheric pressure, in millimeters of mercury and (inches of mercury) °C 795 790 785 780 775 770 765 760 755 750 745 740 735 730 725 720 715 710 705 700 (31.30 (31.10 (30.91 (30.71 (30.51 (30.31 (30.12 (29.92 (29.72 (29.53 (29.33 (29.13 (28.94 (28.74 (28.54 (28.35 (28.15 (27.95 (27.76 (27.56 ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) 14.5 10.6 10.6 10.5 10.4 10.4 10.3 10.2 10.2 10.1 10.0 10.0 9.9 9.8 9.8 9.7 9.6 9.6 9.5 9.4 15.
Model No. PS-2108 Dissolved Oxygen Sensor Temp. Atmospheric pressure, in millimeters of mercury and (inches of mercury) °C 770 765 760 755 750 745 740 735 730 725 720 715 710 705 700 795 790 785 780 775 (31.30 (31.10 (30.91 (30.71 (30.51 (30.31 (30.12 (29.92 (29.72 (29.53 (29.33 (29.13 (28.94 (28.74 (28.54 (28.35 (28.15 (27.95 (27.76 (27.56 ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) 33.5 7.4 7.4 7.3 7.3 7.2 7.2 7.1 7.1 7.1 7.0 7.0 6.9 6.9 6.8 6.8 6.7 6.7 6.6 6.6 6.5 34.0 7.4 7.
PASPort Dissolved Oxygen Sensor Temp. Model No. PS-2108 Atmospheric pressure, in millimeters of mercury and (inches of mercury) °C 695 690 685 680 675 670 665 660 655 650 645 630 625 620 615 610 605 600 640 635 (27.36 (27.17 (26.97 (26.77 (26.57 (26.38 (26.18 (25.98 (25.79 (25.59 (25.39 (24.80 (24.61 (24.41 (24.21 (24.02 (23.82 (23.62 (25.20 (25.00 ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) 8.5 10.7 10.6 10.5 10.4 10.4 10.3 10.2 10.1 10.0 10.0 9.9 9.8 9.7 9.7 9.6 9.5 9.4 9.3 9.3 9.2 9.
Model No. PS-2108 Dissolved Oxygen Sensor Temp. °C Atmospheric pressure, in millimeters of mercury and (inches of mercury) 695 690 685 680 675 670 665 660 655 650 645 630 625 620 615 610 605 600 640 635 (27.36 (27.17 (26.97 (26.77 (26.57 (26.38 (26.18 (25.98 (25.79 (25.59 (25.39 (24.80 (24.61 (24.41 (24.21 (24.02 (23.82 (23.62 (25.20 (25.00 ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) 27.0 7.2 7.2 7.1 7.1 7.0 7.0 6.9 6.9 6.8 6.7 6.7 6.6 6.6 6.5 6.5 6.4 6.4 6.3 6.3 6.2 27.5 7.2 7.1 7.
PASPort Dissolved Oxygen Sensor Model No. PS-2108 Table 2: Salinity correction factors for dissolved oxygen in water (based on conductivity) From R. F. Weiss (1970). Temp ° C, temperature in degrees Celsius; Temp. Conductivity, in microsiemens per centimeter at 25 degrees Celsius °C 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 15000 16000 0.0 1.000 0.996 0.992 0.989 0.985 0.981 0.977 0.973 0.969 0.965 0.961 0.957 0.953 0.950 0.946 0.
Model No. PS-2108 Dissolved Oxygen Sensor Temp. Conductivity, in microsiemens per centimeter at 25 degrees Celsius °C 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 15000 16000 30.0 1.000 0.997 0.994 0.991 0.988 0.985 0.981 0.978 0.975 0.972 0.969 0.966 0.962 0.959 0.956 0.953 0.950 31.0 1.000 0.997 0.994 0.991 0.988 0.985 0.982 0.978 0.975 0.972 0.969 0.966 0.963 0.959 0.956 0.953 0.950 32.0 1.000 0.997 0.994 0.
PASPort Dissolved Oxygen Sensor Temp. Model No. PS-2108 Conductivity, in microsiemens per centimeter at 25 degrees Celsius °C 17000 18000 19000 20000 21000 22000 23000 24000 25000 26000 27000 28000 29000 30000 31000 32000 33000 24.0 0.944 0.941 0.937 0.934 0.930 0.927 0.923 0.920 0.917 0.913 0.910 0.906 0.903 0.899 0.896 0.892 0.889 25.0 0.944 0.941 0.938 0.934 0.931 0.927 0.924 0.921 0.917 0.914 0.910 0.907 0.903 0.900 0.896 0.893 0.889 26.0 0.
Model No. PS-2108 Dissolved Oxygen Sensor Temp. Conductivity, in microsiemens per centimeter at 25 degrees Celsius °C 34000 35000 36000 37000 38000 39000 40000 41000 42000 43000 44000 45000 46000 47000 48000 49000 50000 18.0 0.880 0.877 0.873 0.869 0.866 0.862 0.858 0.855 0.851 0.847 0.843 0.840 0.836 0.832 0.829 0.825 0.821 19.0 0.881 0.877 0.874 0.870 0.867 0.863 0.859 0.855 0.852 0.848 0.844 0.841 0.837 0.833 0.830 0.826 0.822 20.0 0.882 0.
PASPort Dissolved Oxygen Sensor Temp. Model No. PS-2108 Conductivity, in microsiemens per centimeter at 25 degrees Celsius °C 51000 52000 53000 54000 55000 56000 57000 58000 59000 60000 61000 62000 63000 64000 65000 66000 67000 12.0 0.810 0.806 0.802 0.798 0.794 0.791 0.787 0.783 0.779 0.775 0.771 0.767 0.763 0.760 0.756 0.752 0.748 13.0 0.811 0.807 0.804 0.800 0.796 0.792 0.788 0.784 0.780 0.777 0.773 0.769 0.765 0.761 0.757 0.753 0.750 14.0 0.
