隐形眼镜保护液中盐度的测定

Salinity ofContact Lens Solution Star SeriesMethod Note M-1810-E 03/05 RevB Salinity ofContact Lens Solution Analysis Key Words Introduction 1. Place the chloride electrode and stirrer into the beaker with sample such that the electrode tip is fullyimmersed 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. This method provides uncomplicated determination of the salinity of the contact lens solution bymeasuring chloride ion concentration using Known Addition technique and ion selectivechloride electrode. 2.Wait for stable reading (1-2minutes). Record the electrode potential. Known Addition is a technique of adding a small aliquot of the standard of interest to the sample， andcalculating the original sample concentration from the observed change in potential. 3. Pipette 10 mL of standard into the beaker. 4.Wait for stable reading (1-2 minutes). Record the electrode potential. 5. Press the STIRRER key to turn the stirrer off. 6.Subtract the second reading from the first to find AE. 7. From the table in Results section， find the value， Q， which corresponds to the change in potential. · Chloride·Contact LensSolution·Orion ionplusSure-Flow@Combination lonSelective ChlorideElectrode (ISE) 8. Repeat steps 1-7 for additional samples. Remember， rinse electrodes with deionized water between measurements. Upon completion of samples，rinse the electrode with deionized water and store the electrode according to instructions in the ElectrodeStorage section of this method note. Benchtop electrode stand 1110001 5. Volumetric flask (100 mL) Beakers (150 mL) Pipettes (2 mL，5 mL，10 mL) Required Solutions Cat.No. .11. 0.1 M Sodium Chloride Standard 941706 ISA (Ionic Strength Adjuster) for chloride electrode 940011 Reference Filling Solution， Optimum Results""B 900062 4 Deionized water Standard Preparation 1. All samples and standard should be at room temperature. Use a quantity of 0.1 M Sodium ChlorideStandard Solution that， upon addition to the sample， will cause the concentration of the chloride ionto approximately double. Maximum precision will be obtained from a change in reading from about10 mV to about 32 mV. Sample Preparation 1 Pipette 5 mL of the contact lens solution into 100 mL volumetric flask. Dilute to the mark withdeionized water. Add 2 mL ISA. Mix well. 2. Repeat this procedure for measurements on additional samples. Environmental InstrumentsWater Analysis Instruments166 Cummings CenterBeverly， MA 01915 USAM-1810-E 03/05 Rev8250313-001 Toll Free： 1-800-225-1480. Tel： 1-978-232-6000Dom. Fax：1-978-232-6015IntlFax：978-232-6031www.thermo.com/waterO 2005 Thermo Electron CorporationAll rights reserved Registered IS O 9001：2000 Salinity ofContact Lens Solution Results Three samples of the contact lens solution were analyzed using a single known addition method. Chlorideconcentration was calculated using the formula bellow： Csam =Q*Cstd *D Where： Cstd= standard concentration Csam= sample concentration Q = reading from known addition table* D =dilution factor * The table ofQ values is calculated for a 10% volume change for electrodes with slope of58 mV. The equation forthe calculation of Q for different slopes and volume changes is given in the instruction manual for Orion chloride electrode，Orion 94-17 and Orion 96-17. Below an example of calculation for a sample #1： First mV reading-64.3 mV Second mVreading-35.7 mVAE=64.3-35.7=28.6mVThe value， Q， which corresponds to the change in potential= 0.0405Csam， M=0.0405*0.1*20=0.081 Csam，%=0.081*35.45/10=0.29 Contact Lens Solution M Chloride % Chloride Sample # 1： 0.081 0.29 Sample #2： 9.981 0.29 Sample # 3： 9081 0.29 Mean： 0.081 0.29 0.000 Standard Deviation： 0.000 Electrode Storage The solution in the electrode should not be allowed to evaporate， causing crystallization. For short periods oftime， between sample measurements， and up to one week， store the electrode in 0.01 M chloride standard.For storage longer than one week or for an indefinite period， drain the electrode. Flush the inside with distilledwater and store dry with the protective cap to protect the sensing element. Electrode Setup 1. Remove the rubber cap covering the electrode tip. 2. Fill outer chamber with Optimum Result B filling solution. 3. Lift the filling solution bottle’s spout to a vertical position. 4 Insert the spout into the filling hole in the outer sleeve of the electrode and add a small amount of fillingsolution to the chamber. Then tip the electrode to moisten the o-ring at the top and return electrode to avertical position. 5. Holding the electrode by the barrel with one hand， use the thumb to push down on the electrode cap，allowing a few drops of filling solution to drain wetting the inner cone. 6. Release sleeve. 7. If sleeve does not return to its original position immediately， check to see if the o-ring is moist and repeatsteps 4-6 until the outer sleeve has returned to its original position. Add filling solution just bellow thefill hole. Meter Setup For initial meter setup please follow the steps in the Quick Start Guide which is attached to the meter itself.The Quick Start Guide also contains a layout of the meter keyboard for reference. Please note words in allcapitals such as POWER indicate a key on the meter， and words in quotations such as “Unit”indicate a displayon the meter screen. Connect the electrode to the meter.2 Connect the stirrer to the meter. 3. Press the POWER key on the meter to turn the meter on. 4. 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 mV. 5. Press the MEASURE key to return to the measurement mode. If all steps were followed correctly the meter display will show"mV"to the right of the top line. The meter andelectrode are now ready for measurement. Note： The Orion Benchtop Stirrer must be turned on In General instrument Setup before analysis， please see theQuickstart Guide for instructions. www.thermo.com of f f of