废水中营养盐检测方案

Ammonia inWastewater 9Press the LINE SELECTION key to select the bottom line. Press UP or DOWN arrow keys to select“HigH” for “rAng”. Press LINE SELECTION key to accept value. 10. Press LINE SELECTION key to select middle line， and press DOWN arrow key to select “Unit". 11. Press the LINE SELECTION key to select the bottom line. Press UP or DOWN arrow keys to select“mGL” for“Unit". Press LINE SELECTION key to accept value. 12. 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 “ISE： mg/Lto the right of 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 theQuickstart Guide for instructions. Calibration and Analysis 1. Allow all the standards and the samples to attain room temperature for precise measurements since themeasurement is temperature sensitive. 2. Calibrate the meter using the 10 ppm and 100 ppm standards， stirring the standards at a uniform rate.3. Place the electrode and stirrer into the beaker with the 10 ppm standard such that the electrode tip isfully 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. 4. Wait for a stable reading (1-2minutes). Enter standard value of“10.00”using UP and DOWN arrowkeys and the DECIMAL/DIGIT key. 5. Press the CALIBRATE key to accept the 10 ppm standard and press the STIRRER key to turn thestirrer off. 6. Rinse electrode and stirrer thoroughly with deionized water. Gently remove excess solution from theouter sleeve of the electrode by dabbing with a clean paper tissue. 7.Place the probe and stirrer into the beaker with the 100 ppm standard such that the electrode tip isfully 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. 8 Wait for stable reading (1-2 minutes). Enter standard value of“100.00”using UP and DOWN arrowkeys and the DECIMAL/DIGIT key. 9. Press the MEASURE key to accept the 100 ppm standard and to move to the measure mode of themeter. Press the STIRRER key to turn the stirrer off. 10. Rinse electrode and stirrer thoroughly with deionized water. Gently remove excess solution from theouter sleeve of the electrode by dabbing with a clean paper tissue. 11. Place the probe and stirrer in a prepared sample such that the electrode tip is fully immersed in thesolution. Press the MEASURE key on the meter； the stirrer will turn on. The ISE： mg/L icon willflash as the measurement is being made. The ISE：mg/L 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. 12. Repeat steps 10 and 11 for additional samples. ( Environmental Instruments Water Analysis Instruments ) Ammonia inWastewater Introduction The direct measurement of ammonia with the ammonia electrode is a well-established technique that isfrequently used as a standard method of analysis. The method， described below， is approved by both theEPA and ASTM. The method requires no titration and has no turbidity or color interferences. I somecases， pre-distillation may be required. The Orion°9512BNWP gas-sensing electrode allows fast， simple，economical and accurate measurements of dissolved ammonia in wastewater solutions. Recommended Equipment Cat.No. 1. 4 Star benchtop pH/ISE meter 1115000 2. Ammonia electrode 9512BNWP 3. Orion benchtop stirrer (or magnetic stir plate and bar) 096019 4. Benchtop electrode stand 1110001 5. Beakers (150mL) 6. Volumetric flask (100 mL) 7. Pipette (10mL) 8. Graduated cylinder (100 mL) Required Solutions Cat. No. 1. Ammonia standard， 100 ppm ammonia as N standard 951207 2. Ammonia standard， 1000 ppm ammonia as N standard 951007 3.pH adjusting ISA for ammonia electrode 951211 4. Internal filling solution for ammonia electrode 951202 5. pH 4.01 buffer， color coded pink 910104 6. Replacement membranes， 20 loose 951204 7.Deionized water Calibration Standard Preparation 1 Prepare a 10 ppm standard by pipetting 10 mL of the 100ppm ammonia standard into a 100 mLvolumetric flask. Dilute to the mark with deionized or deionized water. Mix well. .22. Transfer 100 mL of the 100 ppm ammonia standard into a beaker. Just prior to the calibrationreading， add 2 mL of the pH adjusting Ammonia reagent. In all analytical procedures， pH-adjustingISA must be added to all standards and samples immediately before measurement. After addition ofthe ISA all solutions should fall within a pH 11-14 range (In this range the solutions are blue). 3 Transfer 100 mL of the 10 ppm ammonia standard into a beaker. Just prior to the calibration reading，add 2 mL of the pH adjusting Ammonia reagent. Sample Preparation 1. Using a graduated cylinder， measure 100 mL of the sample into a beaker. Just prior to themeasurement， add 1 mL of the pH adjusting Ammonia reagent. 2. Repeat for additional measurements. Results Five aliquots of effluent wastewater sample were measured for ammonia. The table bellow provides results forthese samples. Wastewater ppm Ammonia Sample # 1： 15.7 Sample #2： 14.9 Sample # 3： 15.2 Sample #5： Sample #4： 15.914.4 Mean： 15.2 Standard Deviation： 0.61%CV： 4.0 Electrode Storage Between measurements， keep the electrode tip immersed in 10 ppm ammonia standard with added ISA. Forovernight or week long storage， the electrode tip should be immersed in 1000 ppm ammonia standard withoutadded ISA .For storage over one week disassemble electrode completely and rinse the inner body， outer body，and bottom cap with deionized water. Dry and reassemble electrode without filling solution or membrane. Equipment Setup Electrode Setup-Ammonia Electrode Note： Soak inner body in electrode filling solution for at least two hours before assembling electrode. For best results， soakinner body overnight. 1.While holding the probe vertically， unscrew the top cap (a) and carefully remove the glass electrode innerbody (b) from the electrode outer body (c) (See Fig. 1). Set cap with inner body aside carefully. Pour outremaining electrode filling solution from outer body ifapplicable， new probe will not have any filling. solution in the body. 2 Unscrew membrane cap (d) from outer body (See Fig.2). Remove old membrane， if applicable. 3. Wearing gloves use tweezers to carefully grasp corner of white membrane from between paper separators(See Fig. 3). Do not to touch center of membrane. 4 With free hand， grasp electrode outer body with threads oriented to the top. Align straight edge ofmembrane against threaded shoulder and hold with thumb (See Fig. 4). With other hand，gently stretchthe membrane upwards (See Fig.5)， then across the opening (See Fig.6)， then down to align other edgewith the opposite shoulder (See Fig.7). While holding each edge on both sides， gently stretch each serratedside of the membrane out and down over threads making sure that membrane surface is smooth andwithout wrinkles (See Fig.8). Smooth any loose material taking care not to touch center of membrane(See Fig. 9). Note： Do not overstretch the membrane. The membrane is considered overstretched ifthe black body material can be seenthrough the membrane. Discard membrane ifoverstretched and replace with new membrane. Continue from Step 3. 5 Replace membrane cap being careful not to touch membrane center (See Fig.10). Screw down half wayand tuck any loose membrane material under cap while twisting. Make sure cap is fully screwed on. 6. Fill the outer body with 2.5 mL filling solution， or approximately 50 drops from the bottle (See Fig.11). 7.Place inner body into outer body containing filling solution and screw on upper cap (See Fig. 12). 8 Carefully shake fully assembled electrode as if it were a clinical thermometer to remove bubbles. Gentlypull spring loaded cable back and slowly release to allow filling solution to migrate between membrane andglass electrode inner body (See Fig. 13). 9. Rinse the electrode well and wipe dry. H Meter Setup-4 Star benchtop 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 indicates akey on the meter， and words in quotations such as “Unit"indicates adisplay on the meter screen 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 not active， pressthe LINE SELECTION key to change the selected line to the top line. Then press the UP or DOWNarrow keys to change the measurement mode of the top line to ISE. 5. Press the SETUP key to enter ISE Setup. Press the LINE SELECTION key to select the bottom line.Press UP or DOWN arrow keys to select “3”for "rES". Press LINE SELECTION key to accept value. Press LINE SELECTION key to select middle line， and press DOWN arrow key to select“nLln”. 7 Press the LINE SELECTION key to select the bottom line. Press UP or DOWN arrow keys to select“off” for “nLln". Press LINE SELECTION key to accept value. www.thermo.com of of of of