美发产品中pH的测定

pHofHair Care Products Calibration and Analysis 1. Allow all the standards and the samples to attain room temperature for precise measurements since the. measurement is temperature sensitive. 2. Calibrate the meter using the pH 7 and pH 4.01 buffers， stirring the solutions at a uniform rate. 3. P]lace the electrode， ATC probe， and stirrer into the beaker with the pH7 buffer such that theelectrode tip is fully immersed in the solution. The stirrer should be positioned slightly below the tipof the electrode. Press the STIRRER key on the meter to turn the stirrer on. Press the CALIBRATEkey. 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 and then with the nextstandard to be measured. 7.Place the electrode and stirrer into beaker with the pH 4.01 buffer standard with the electrode tip fullyimmersed in the solution. The stirrer should be positioned slightly below the tip of the electrode. Pressthe STIRRER key on the meter to turn the stirrer on. 8.Wait for stable reading (1-2 minutes). Enter standard of 4.01 using the UP and DOWN arrow keysand the DECIMAL /DIGIT key. 9.Press MEASURE key to accept 4.01 standard and to move to the measure mode of the meter. Pressthe STIRRER key to turn the stirrer off. 10. Rinse the electrode， ATC， and stirrer thoroughly with deionized water and then with the next solutionto be measured. 11. Place the electrode， ATC and stirrer into prepared sample with the electrode tip fully immersed in thesolution. Press the MEASURE key on the meter； the stirrer will turn on. The pH icon will flash as themeasurement is being made. The pH icon will become solid and the display value will freeze when astable reading is achieved. This value is logged and printed automatically and the stirrer turnsoff automatically. 12. Repeat steps 10 and 11 for additional samples. Remember to rinse the electrodes with deionized waterbetween measurements. Penetrate each sample to the same depth to reproduce sample measurement.Upon completion of samples， rinse the electrode with deionized water and store the electrodeaccording to instructions in the Electrode Storage section of this method note. pH ofHair Care Products Introduction The following method utilizes the Orion ROSS Ultra° Combination with epoxy body， semi-micro pHelectrode to measure pH in Hair Care Products， such as Shampoo and Conditioners.The ROSS Ultra Combination pH electrodes make measurements quickly and precisely. Recommended Equipment Cat. No. pH of Hair Care Products Application Package (includes all items with a Cat. No.) 1010160 1. 3-Star benchtop pH meter 1112000 2. ROSS Ultra Combination with epoxy body， semi-micro 8115BNUWP 3. ATC probe 927006MD 4. Orion benchtop stirrer (or magnetic stir plate and bar) 096019 5. Orion benchtop electrode stand 1110001 6. Beakers (100 mL) 7. Graduated cylinders (100 mL) Required Solutions Cat.No. 1. pH 4.01 Buffer (color coded pink) 910104 2. pH 7.00 Buffer (color coded yellow) 910107 3. pH 10.00 Buffer (color coded blue) 910110 4. ROSS reference filling solution 810007 5. Electrode storage solution 910001 6. Deionized water Calibration Standard Preparation 1. Ensure that all buffers are at the same temperature. 2. Using a graduated cylinder， transfer 60 mL of the pH 7.00 buffer into a 100 mL beaker. 3. Using a graduated cylinder， transfer 60 mL of the pH 4.01 buffer into a 100 mL beaker. Sample Preparation Weigh 5 g sample in the 100 mL beaker， add 50 g of deionized water. Mix sample with Orion stirrer. 2 Repeat this procedure for additional measurementsS. Results Five samples of the shampoo and five samples of the conditioner， prepared as 10 % (w/w) aqueous solution， aremeasured. The results provide a representative results expected for pH in shampoo and conditioner. Shampoo pH Conditioner pH Sample #1： 5.28 Sample #1： 4.79 Sample #2： 5.28 Sample#2： 4.84 Sample #3： 5.27 Sample#3： 4.85 Sample #4： 5.27 Sample#4： 4.86 Sample #5： 5.27 Sample #5： 4.88 Mean： 5.27 Mean： 4.84 Standard Deviation： 0.005 Standard Deviation： 0.034 %CV： 0.104 %CV： 0.694 Electrode Storage For short-term storage， soak electrode in pH Electrode Storage Solution， Cat. No. 910001. For long-termstorage period， the reference chamber should be filled and the fill hole securely covered. Cover the sensingelement and reference junction with its protective cap containing a few drop of storage solution. Equipment Setup Electrode Setup-ROSS Ultra" 1. Remove the protective shipping cap from 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 coverthe coil and 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 thereference junction. Once junction is wet， do not allow the electrode to dry out. 5. Shake down the electrode to remove air bubbles. For initial meter setup， follow the steps on the Quick Reference Guide that is attached to the meter itself.The Quick Start Guide also contains a layout of the meter keypad for reference. The words in this methodrepresented 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. 1. Connect the electrode to the meter. 2.Connect the stirrer to the meter. 3.Press the POWER key on the meter to turn meter on. 4.Note that the arrow on the left of the screen indicates the active line. If not the top line is active， press theLINE SELECTION key to change the selected line to the top line. Then press the UP or DOWNarrowkeys to change the measurement mode of the top line to pH. 5.Press the SETUP key to enter pH Setup. Press the LINE SELECTION key to select the middle line.Press the UP or DOWN arrow keys to select “rES”， which is resolution. 6.Press the LINE SELECTION key to select the bottom line. Press UP or DOWN arrow keys to select“0.01” for “rES”， which is an abbreviation for resolution or number of significant digits. Press LINESELECTION key to accept value. 7.1Press LINE SELECTION key to select middle line， and press DOWN arrow key to select “bUF”， which iswhich is pH buffer. 8.Press the LINE SELECTION key to select the bottom line. Press UP or DOWN arrow keys to select“USA”which is US/Orion buffers. Press LINE SELECTION key to accept value. 9P.ress the LINE SELECTION key to accept and select the pH setup menu line (top line). 10. Press MEASURE key to return to 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 Setupbefore analysis， please see the Quick-Start Guide for instructions. of of