隐形眼镜保护液中pH的测定

pH ofSaline SolutionpH ofSaline Solution pH ofSaline Solution Star SeriesMethod Note M-1808-E 03/05 RevB Calibration and Analysis ·pH Introduction 1. Allow all the standards and the samples to attain room temperature for precise measurements， sincethe measurement is temperature sensitive. 2.Calibrate the meter using the pH 7.00 buffer followed by the pH 4.01 (or 10.01) buffer， stirring thestandards at a uniform rate. ·Saline Solution forContact Lenses·Orion ROSSTMpH Electrode This method describes a procedure for the determination of the pH of multi-purpose contact lens solution.The ROSS" electrode offers stable， fast results regardless of sample composition. Results are three to fivetimes more precise than those obtained with conventional electrodes. 3.P1lace electrode， ATC probe and stirrer into beaker with pH 7.00 buffer standard with the electrode tipfully immersed in the solution. The stirrer should be positioned slightly below the tip of the electrode.Press the STIRRER key on the meter to turn the stirrer on. Press the CALIBRATE key. Recommended Equipment Cat. No. pH Application Package (includes all items with a Cat. No.) 1010165 4.Wait for stable reading (1-2 minutes). Enter standard value of 7.00 using the UP and DOWN arrowkeys and the DECIMAL/DIGIT key. 5. Press CALIBRATE key to accept 7.00 standard and press the STIRRER key to turn the stirrer off. 6.Rinse electrode， ATC probe， and stirrer thoroughly with deionized water. Gently remove excesssolution from the outer sleeve of the electrode by dabbing with a clean paper tissue. Do not wipe orrub the sensing element of the electrode. 7.Place the electrode and stirrer into beaker with the pH 4.01 (or 10.01) buffer standard with theelectrode tip fully immersed in the solution. The stirrer should be positioned slightly below the tip ofthe electrode. Press the STIRRER key on the meter to turn the stirrer on. 8.Wait for a stable reading (1-2 minutes). Enter standard of 4.01 (or 10.01) using the UP and DOWNarrow keys and the DECIMAL/DIGIT key. 9.Press MEASURE key to accept 4.01 (or 10.01) standard and to move to the measure mode of themeter. Press the STIRRER key to turn the stirrer off. 10. Rinse the electrode， ATC probe and stirrer thoroughly with deionized water. Gently remove excesssolution from the outer sleeve of the electrode by dabbing with a clean paper tissue. Do not wipe orrub the sensing element. 1. 3-Star benchtop pH meter 1112000 2. ROSS Semi Micro Combination 8103BNUWP 3. ATC probe 927005MD 4. Orion stirrer or magnetic stir plate and bar 096019 5. Benchtop electrode stand 1110001 Beakers (50 mL) 7. Beaker watch glass Required Solutions Cat. No. 1. pH 4.01 buffer， color coded pink 910104 2. pH 7.00 buffer， color coded yellow 910107 3. pH 10.01 buffer， color coded blue 910110 4. ROSS reference filling solution(packaged with the 8103BNUWP) (packaged with the 8103BNUWP) 810007 11. Place the electrode， ATC probe and stirrer into the prepared sample with the electrode tip fullyimmersed in the solution. Press the MEASURE key on the meter； the stirrer will turn on. The pHicon will flash as the measurement is being made. The pH icon will become solid and the display valuewill freeze when a stable reading is achieved. This value is logged and printed automatically and thestirrer turns off automatically. 5. Orion pH storage solution 910001 6.Deionized water Calibration Standard Preparation Remember to rinse electrodes with deionized water between measurements. Penetrate each sample to thesame depth to reproduce sample measurement. Upon completion of samples， rinse the electrode withdeionized water and store the electrode according to instructions in the Electrode Storage section of thismethod note. 1. Ensure that all buffers are at the same temperature. If samples are at varying temperatures， temperaturecompensation is recommended. 2.Select two buffers that bracket the expected sample pH. The first should be near the electrode isopotential point (pH 7) and the second near the expected sample pH. Sample Preparation 1. Ensure that the test sample is well conditioned to room temperature. 2.DIispense approximately 40-50 mL of sample into a beaker. Add a magnetic stir bar to the beaker andcover the beaker with a watch glass. 3. Repeat this procedure for additional measurements. ( Environmental Instruments Water Analysis Instruments ) www.thermo.com ( 1 66 Cummings C enterBeverly， MA 01915 USAM-1808103/05 feYi 2503 1 1-0 0 1 ) Toll Free： 1-800-225-1480Tel：1-978-232-6000Dom.Fax：1-978-232-6015IntlFax：978-232-6031www.thermo.com/waterO 2005 Thermo Electron Corporation RegisteredIS O9001：2000 All rights reserved Results Five aliquots of saline solution were measured for pH. The results obtained demonstrate a good repeatabilitybetween replicate tests. Saline Solution pH Sample #1： 7.26 Sample #2： 7.27 Sample #3： 7.28Sample # 4： 7.27Sample # 5： 7.27 Mean： 7.27 Standard Deviation： 0.01 %CV： 0.10 Electrode Storage For short-term storage， soak the electrode in pH Electrode Storage Solution (Cat. No. 910001).For long-term storage， the reference chamber should be filled and the filling hole covered. Cover the sensingelement and reference junction with its protective cap containing a few drops of pH storage solution.There are no special storage requirements for the ATC probe. Equipment Setup Electrode Setup - ROSS° Semi Micro Combination 1.Remove the protective shipping cap from the sensing element and save for storage. 2.Clean any salt deposits from exterior by rinsing with deionized water. 3. Uncover filling hole by removing plastic sleeve， and add ROSS° Internal Filling Solution (Cat. No.810007) to electrode. To maintain an adequate flow rate， the level of filling solution must cover the coiland be at least one inch above the sample level when immersed. 4 Place the electrode in the electrode holder and suspend in air for 15 minutes to thoroughly wet the reference junction. Once the junction is wet， do not allow the electrode to dry out. For initial meter setup， follow the steps on the Reference Panel that is attached to the meter itself. The QuickStart Guide included with each meter also contains a layout of the meter keypad for reference. The words inthis method in all capital letters such as POWER indicate a key on the meter， and words in quotations such as“Unit”indicate information on the meter display. Connect the electrode to the meter 2. Connect the temperature probe to the meter. 3. Connect the stirrer to the meter. 4. Press the POWER key on the meter to turn the meter on. 5. Note that the arrow on the left of the screen indicates the active line. If the top line is not active， press theLINE SELECTION key to change the selected line to the top line. Then press the UP or DOWN arrowkeys to change the measurement mode of the top line to pH. 6， Press the SETUP key to enter p Setup. Press the LINE SELECTION key to select the middle line. Pressthe UP or DOWN arrow keys to select “rES”which is an abbreviation for resolution. 7. Press the LINE SELECTION key to select the bottom line. Press the UP or DOWN arrow keys to select“0.001”for "rES”which is an abbreviation for resolution or number of significant digits. Press the LINESELECTION key to accept setting. 8 Press the LINE SELECTION key to select the middle line， and press the UP or DOWN arrow keys toselect “bUF”which is an abbreviation for pH buffer. 9 Press the LINE SELECTION key to select the bottom line， and press the UP or DOWN arrow keys toselect“USA”which is an abbreviation for US/Orion buffers. 10. Press the LINE SELECTION key to accept the setting and select the pH Setup Menu line (Top Line). 11. Press the MEASURE key to return to the measurement mode. If all steps were followed correctly the meter display will show three digits in the top line and“pH" to the rightof the top line. The meter and electrode are now ready for calibration. Note： The Orion Benchtop Stirrer must be turned on in General Instrument Setup before analysis， please see the Quick StartGuide for instructions. of of