啤酒中溶解氧检测方案

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Dissolved Oxygenin Wine/Beer Star SeriesMethod Note M-1407-E 03/05 RevB Dissolved Oxygenin Wine/Beer Calibration and Analysis ·Dissolved Introduction 1. Allow all the standards and the samples to attain room temperature for precise measurements， sincethe measurement is temperature sensitive. 2 Prior to calibration of the meter ensure that the probe has polarized for at least 30 to 50 minutes，thecalibration sleeve (included with the 083010MD electrode) has had at least 10 to 15 minutes to attainproper humidity or air saturated water samples have been properly aerated with oxygen. Oxygen·Wine/Beer·DissolvedOxygen Probe 3. Place the electrode into the calibration sleeve and insure that the calibration sleeve is wet and has beengiven proper time to come to equilibrium. Wineries have recently become concerned with the oxygen incorporation in wine during the bottlingprocess. This is an extremely important issue influencing wine quality， stability and longevity. Theconcentration of molecular oxygen should be measured in the wine before bottling begins and should beless than 0.5 mg/L. If the concentration of oxygen is greater than 0.5 mg/L， it can generally be lowered bysparging with nitrogen gas (see Zoecklein et al.， 1995). The Orion 083010MD polarographic dissolvedoxygen probe offers convenience， quick response and long life between servicing. This dissolved oxygenprobe requires no zero current adjustment， while providing accurate results with ease. 4. Press the CALIBRATE key to activate calibration. Recommended Equipment Cat.No. .5. Once the input has stabilized， 101.7% saturation will be displayed for 3 seconds. Then the meter willreturn to measurement mode. Dissolved Oxygen Application Package (includes all items with a catalog number) 1010138 7.Rinse electrode thoroughly with deionized water. Gently remove excess solution from the outer sleeveof the electrode by dabbing with a clean paper tissue. Do not wipe or rub the sensing element. 1. 3-Star portable dissolved oxygen meter 1214000 2. Dissolved oxygen probe (polarographic) 083010MD 8.Place the electrode in a prepared sample with the electrode tip fully immersed in the solution. 3. Electrode storage sleeve 1210003 9. Obtain and record reading (after 3 minutes have elapsed). The result is displayed in mg/L of the 4. Soft field case 1210004 dissolved oxygen. 5. Magnetic stir plate and stir bars Upon completion of samples， rinse electrode with deionized water and store the electrode according to theinstructions in the Electrode Storage section of this method note. Required Solutions Cat. No. 1.Electrolyte Solution 0 8 0 5 1 4 2.D1eionized water Sample Preparation Open a wine sample bottle just before test， and add a suitable stir bar into the sample’s bottle. 2Place the bottle on a stirrer-plate. Stir very gently.3 Insert the DO electrode in the wine sample bottle to a depth where the electrode tip is close to thebottom of the bottle. 4. Repeat this procedure in another bottle for additional measurements. Results Wine Samples were taken from five bottles of wine and measured for dissolved oxygen. The data in the tablebelow is representative of the results expected for dissolved oxygen in wine. WineDissolved Oxygen mg/LSample #1：0.07Sample #2：0.09Sample #3：0.07Sample #4：9.96Sample #5：0.06 Environmental InstrumentsWater Analysis Instruments166 Cummings CenterBeverly， MA 01915 USAM-1407-E 03/05 RevB248099-001 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 Registered Is O 9001：2000 All rights reserved 4 of 4 Mean： 0.07 Standard Deviation： 0.01 %CV： 14.2 Note： The results were recorded after 3 minutes elapsed time. Beer Samples were taken from five bottles of beer and measured for dissolved oxygen. The data in the table below isrepresentative of the results expected for dissolved oxygen in beer. Beer Dissolved Oxygen mg/LSample #1： 0.24 Sample#2： 0.17 Sample#3： 0.17 Sample # 4： 0.18 Sample# 5： 0.20 Mean： 0.19 Standard Deviation： 0.03 %CV： 15.4 Note： I) The results were recorded after 3 minutes elapsed time. 2) Due to the carbonation in beer， results are variable. Electrode Storage For short-term storage， overnight or between measurements， the probe should be kept in a moist environment.The probe should remain plugged into the meter and stored in the calibration sleeve， BOD bottle or instrument quiver. For long-term storage， disconnect the probe from the meter， remove the membrane cap clean and Equipment Setup Electrode Setup -Dissolved Oxygen Probe Probes are shipped with membrane caps， electrolyte， and polishing paper. Fill the cap assembly halfway with electrolyte. Make sure that there are no bubbles on the insideof the membrane. . 2 While holding the probe vertically， so that the sensing tip is oriented downward， screw the membrane caponto the probe. Allow air and excess electrolyte to overflow from the cap via the channel in the threads.Tighten until "finger tight". 3.The probe is continuously polarized when connected to the instrument. 4. Polarization for a new probe， after the silver anode is cleaned， or when the probe has been unplugged formore than an hour， will take 30 to 50 minutes. Interrupted connections of less than an hour will takebetween 5 and 25 minutes to repolarize. Meter Setup For initial meter setup， follow the steps on the Reference Panel that is attached to the meter itself. The QuickStart Guide also contains a layout of the meter keypad for reference. The words in this method represented inall capital letters such as POWER indicate a key on the meter， and words in quotations such as “Unit"indicateinformation on the meter display. 1. Connect the DO Probe to the meter. 2.Press the POWER key on the meter to turn the meter on. .Note that the arrow on the left of the screen indicates the active line. If the bottom line is not active， pressthe LINE SELECTION key to change the selected line to the bottom line. The DO measurement isactive. 4P.ress the SETUP key to enter DO Setup. Press the LINE SELECTION key to select the middle line. Pressthe UP or DOWN arrow keys to select “rES”mg/L. 5.Press the LINE SELECTION key to select the bottom line. Press the UP or DOWN arrow keys to select“0.01"with mg/L for "rES”which is an abbreviation for resolution and the desired result units (mg/L or %sat). Press the LINE SELECTION key to accept setting. 6.Press the LINE SELECTION key to select the middle line， and press the DOWN arrow key to select“SAL” salinity correction factor type (Auto/Manual). 7.Press the LINE SELECTION key to select the bottom line. Press the UP or DOWN arrow keys to select“SAL”. Press the LINE SELECTION key to accept“mAn". 8.Press the LINE SELECTION key to select the middle line. Press the UP or DOWN arrow keys to select“SALF”. ：9.Press the LINE SELECTION key to select the bottom line. Press DECIMAL/DIGIT key and UP orDOWN arrow keys to select “0”for "SALF”. Press the LINE SELECTION key to accept setting. 10. Press the LINE SELECTION key to select the middle line， and press the DOWN arrow key to select"bAr"which is an abbreviation for barometric pressure compensation type (Auto/Manual). 11. Press the LINE SELECTION key to select the bottom line. Press the UP or DOWN arrow keys to select“AUtO” for barometric pressure compensation type. Press the LINE SELECTION key to accept setting. 12. Press the LINE SELECTION key to select the middle line， and press the UP or DOWN arrow keys toselect“CALt”to select the DO Calibration type selection. 13. Press the LINE SELECTION key to select the bottom line. Press the UP or DOWN arrow keys to select“Air"for“CALt". Press the LINE SELECTION key to accept setting. 14. Press the MEASURE key to return to the measurement mode. If all steps were followed correctly the meter display will show two digits in the bottom line and “mg/L"to theright of the bottom line. The meter and electrode are now ready for calibration. www.thermo.com of ofof