Thermo Products 9678BNWP manuale d’uso

Thermo Fisher Scientific Environmental Instruments W ater Analysis Instruments 166 Cummings Center Beverly , MA 01915 USA T el: 978-232-6000 T oll Free: 800-225-1480 Dom. Fax: 978-232-6015 Int’l. Fax: 978-232-6031 www .thermo.com/water User Guide Redox/ORP Electrodes[...]

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1 Redox/ORP Electrode User Guide Introduction This user guide contains information on the preparation, operation and maintenance of the T hermo Scientific Orion ORP electrodes. T hese ORP electrodes combine a platinum redox sensing electrode and a silver/silv er c hloride ref erence electrode in one body . The redo x/ORP electrodes can be used to [...]

2 Redox/ORP Electrode User Guide Required Equipment 1 . Thermo Scientific Orion pH/mV meter , suc h as the 3-Star pH meter , 4-St ar pH/ISE meter , 4-Star pH/DO meter , 4-St ar pH/conductivity meter or 5-St ar pH/ISE/DO/conductivity meter . ORP electrodes can be used on any pH/mV meter with a BNC or U.S . standard connection. The electrodes can al[...]

3 Redox/ORP Electrode User Guide Sample Requirements Electrodes with an epoxy body should only be used in aqueous solutions. Electrodes with a glass body may be used in non-aqueous solutions and solutions that contain organic solvents. The ORP electrodes contain a silver/silv er c hloride (A g/AgCl) ref erence that may become clogged in solutions t[...]

4 Redox/ORP Electrode User Guide Electrode Preparation Electrode Preparation for Refillable Electrodes 1 . Remo ve the protectiv e shipping cap from the sensing element and sav e the cap for storage. 2. Clean any salt deposits from the e xterior of the electrode by rinsing with distilled water . 3. Uncov er the filling hole by remo ving the tape [...]

5 Redox/ORP Electrode User Guide filling hole Ag/AgCl internal reference filling solution chamber ceramic reference junction sensing element fill hole AgAgCl internal reference reference filling solution chamber Sure-Flow junction sensing element Figure 1– Refillable ORP Electr ode filling hole Ag/AgCl internal reference filling solution c[...]

6 Redox/ORP Electrode User Guide Electrode Calibration ORP readings can be reported using the absolute mV values or the E H mV values. E H mV v alues give the cor responding mV values that w ould be obtained using a St andard Hydrogen Electrode (SHE), also known as the Normal Hy drogen Electrode (NHE). Orion ORP standard, Cat. No. 96790 1 or 967961[...]

7 Redox/ORP Electrode User Guide T emperat ur e (°C) E H V alue (mV) Absolute V alue with Cat. No . 900 0 1 1 Filling Solution (mV) Absolute V alue with Cat. No . 900 00 1 Filling Solution (mV) 1 0 431 219 1 75 1 1 430 219 1 75 1 2 430 219 1 75 1 3 429 219 1 75 1 4 428 219 1 75 1 5 428 219 1 75 1 6 427 219 1 7 4 1 7 426 219 1 7 4 18 425 219 1 7 4 [...]

8 Redox/ORP Electrode User Guide Measurement T echniques • Alwa ys use fresh ORP standard for calibration. • If the electrode is refillable, remov e the filling hole cov er during measurements to ensure a uniform fl ow of filling solution. • Between measurements, thoroughly rinse the electrode with distilled water . Gently shake the elect[...]

9 Redox/ORP Electrode User Guide Electrode Measurements Direct Measurements Direct oxidation-reduction potential (ORP) measurements can be used to determine the oxidizing or reducing capability of a solution and are commonly made in polluted streams, c hlorinated w aters, industrial waste waters and other w ater samples. 1 . Prepare the electrode a[...]

10 Redox/ORP Electrode User Guide Oxidation-Reduction T itrations Oxidation-reduction or redox titrations pro vide a simple, reliable method for determining man y substances in solution. A redox titration consists of adding to an unkno wn sample small increments of a titrant that conv erts the unknown to a dif f erent oxidation state. Af ter eac h [...]

11 Redox/ORP Electrode User Guide 6. Calculate the normality of the sample, N x , in equivalents per liter . N x = (V t * N t ) / V x where: N t = normality of titrant (Eq/1) V t = volume of titrant at end point (mL) V x = volume of sample (mL) T able 2 Refer ences: 1 . F urman (ed.), Scot t’ s St andard Methods of Chemical Analysis, 5th Ed., V a[...]

12 Redox/ORP Electrode User Guide T able 2– T ypical Redo x Titration Methods Unknown Int erf er ences antimony (Sb +3 ) As, F e, SO 2 , V , and organic substances arsenic (As +3 ) other reducing agents hy drogen peroxide (H 2 O 2 ) preser vativ es present in commercial H 2 O 2 may interf ere hypoc hlorite ion (ClO ¯ ) or c hlorine (Cl 2 ) Br 2 [...]

13 Redox/ORP Electrode User Guide Suitable Titrants Titration Reaction Ref potassium permanganate (KMnO 4 ) 5Sb +3 + 2MnO 4 ¯ + 1 6H + –› 5Sb +3 + 2Mn +2 + 8H 2 O 2 sodium bromate (NaBrO 3 ) BrO 3 ¯ + 3As +3 + 6H + – › Br¯ + 3As +5 + 3H 2 O 3 potassium permanganate (KMnO 4 ) 5H 2 O 2 + 2MnO 4 ¯ + 6H + – › 5O 2 + 2Mn +2 + 8H 2 O 5 so[...]

14 Redox/ORP Electrode User Guide Electrode Maintenance 1 . Inspect the electrode for scratc hes, cracks, salt crystal buildup, or membrane/junction deposits. 2. Rinse of f any salt buildup with distilled w ater . Remo ve an y membrane/junction deposits as directed in the General Cleaning section. 3. If the electrode is refillable, drain the ref e[...]

15 Redox/ORP Electrode User Guide Electrode Cleaning Procedures General Cleaning 1 . Soak the electrode in 0.1 M HCl or HNO 3 for half an hour . The electrode can also be soak ed for 1 5 minutes in a 1:1 0 dilution of household laundr y bleac h or a 0.1 to 0.5% liquid detergent solution mixed with hot w ater . The solution should be stirred at a mo[...]

16 Redox/ORP Electrode User Guide Sure-Flow Electrode Cleaning Cat. No. 9678BNWP and 967800 If the area between the electrode sleev e and inner cone becomes clogged with sample or precipitate, flush the area with filling solution or distilled water . 1 . Hold the electrode body with one hand and use your thumb to push down on the electrode cap to[...]

17 Redox/ORP Electrode User Guide Reassembling the Sure-Flo w Electr ode 1 . Moisten the O-ring on the electrode body with a drop of filling solution. Insert the screw -thread end of the electrode body into the tapered, ground end of the sleeve. 2. Push the body into the slee ve using a gentle twisting motion until the bot tom surf ace of the inne[...]

18 Redox/ORP Electrode User Guide T roubleshooting F ollow a sy stematic procedure to isolate the problem. The measuring system can be divided into f our components for ease in troubleshooting: meter , electrode, sample/application and tec hnique. Meter The meter is the easiest component to eliminate as a possible cause of error . Thermo Scientifi[...]

19 Redox/ORP Electrode User Guide Checking Electrode Operation Chec king the electrode is necessary only when there is evidence of malfunction that cannot be traced to other causes. Fill the electrode with Cat. No. 900 0 1 1 filling solution for this testing procedure. 1 . Prepare solution A (0.1 M potassium fer rocyanide and 0.05 M potassium ferr[...]

20 Redox/ORP Electrode User Guide Ordering Information Cat. No . Descr iption 9179BNMD L o w maintenance gel ORP/A TC T riode with epoxy body and w aterproof BNC and 8 pin MiniDIN connectors 9179BN L o w maintenance gel ORP/A TC T riode with epoxy body and BNC and 8 pin DIN connectors 9180BNMD R efillable ORP/A TC T riode with epoxy body and water[...]

Thermo Fisher Scientific Environmental Instruments W ater Analysis Instruments 166 Cummings Center Beverly , MA 01915 USA T el: 978-232-6000 T oll Free: 800-225-1480 Dom. Fax: 978-232-6015 Int’l. Fax: 978-232-6031 www .thermo.com/water 254794-001 Rev .A[...]