pH and Reference Electrode Manual
Contents
1. the following steps and calibration are successfully completed IMPORTANT If you havea pH MR electrode calibrate in the protective tube and then carefully move the sensor from this tube into the provided blue guide 11 exposure to air CONNECTING THE ELECTRODES Connect the Unisense pH micro electrode to the amplifier Connect the reference electrode to the black box on the pH electrode cable banana plug connection Immerse the pH electrode still in its protective tube in a buffer 7 solution Place the tip of a reference electrode in the same solution Unisense pH electrode with internal reference has to be submerged sufficiently 2 3 cm in the medium to cover the liquid junction during all measurements In the following we assume that you are using Unisense pH mV Meter If you are using another meter perform analogous steps with the mV meter in question Also please see note in the margin of this page CALIBRATION Please consult the software manual for instruction on how to calibrate in the software Connect the pH mV Meter to your computer and start your SensorTrace program If you are using a strip chart recorder or other data acquisition device connect this to the output connections of the pH mV Meter Expose both the reference electrode and pH micro electrode tip to at least three different pH buffers covering the range in which measurements are to be made Record the signal size in your2. For long term storage the electrode tip can be immersed in demineralized water in the tube For short term storage lt 10 min the electrodes can be stored in air The room in which the electrodes are stored should be dry and not too hot 5 35 C Between measurements leave the electrode in KCI solution Overnight or longer seal the filling hole with paraffin film or with the electrode clip and fit back in place the protection cap filled with the 3M KCI solution MICRO REFERENCE ELECTRODE Store in the protective glass tube used for shipping For short term storage 10 min the electrodes can be stored in air For long term storage the electrode tip must be immersed in 1M KCI in the protective casing used for shipping The room in which the electrodes are stored should be dry and not too hot 10 25 CLEANING THE ELECTRODE The pH electrode can be cleaned by flushing it with 7096 ethanol or 0 01 M HCI for a couple of minutes After this rinse with pH 4 01 The Ref RM electrode should be rinsed with distilled water after measurements Check the level of filling solution often In case of deposits please consult the separate manual in the back of this manual The micro reference electrodes can be cleaned by flushing or submergence in 7096 ethanol for a couple of minutes After this rinse with 1M KCI WARNING The tip of the pH electrode should be kept in aqueous solution at all times it can however
3. please view description under pH combination electrode 10 GETTING STARTED UNPACKING NEW PH ELECTRODE When receiving a new micro electrode remove the shock absorbing grey plastic net Remove the lower piece of black tape and the rubber stopper in order to empty the tube of storage liquid This liquid can be saved for future storage Remove the clear tape covering the hole just below the screw This will expose small hole in the protection tube and allow the liquid to run out The sensor is now ready for calibration NOTE if you have pH MR electrode calibrate in the protective tube and then carefully move the sensor from this tube into the provided blue guide UNPACKING A NEW REFERENCE ELECTRODE REF RM 1 Remove the protection cap from the electrode and any seals covering the filling hole Before starting a measurement remove the clip which closes the electrode filling hole Remember to replace the clip at the end of measurements Check the level of the filling solution It should be approximately 0 5 cm below the filling hole If necessary refill the KCI Ag 3M KCI solution saturated with AgCl UNISENSE REFERENCE ELECTRODE Follow 1 2 under pH electrode The tip of the Unisense reference electrode not the Ref RM electrode should be kept immersed in water or an aqueous solution at all times but can tolerate up to 10 minutes of WARNING Do not remove the seal and protective plastic tube before
4. software for each pH buffer The pH micro electrode should respond linearly between these points with a slope of 50 70 mV pH unit Millivolt readings during subsequent measurements can be converted to pH values with a linear conversion using the calibration values This can be done directly in the SensorTrace software please see the software manual for instructions IMPORTANT As the pH micro electrode is sensitive to temperature it is necessary to perform calibration and measurements at the same temperature NOTE Conventional pH meters often have an automated calibration procedure However due to the very small area ofpH sensitive glass on the electrodes this does not work well Therefore Do NOT use the auto calibration but read the signal in mV and convert it to pH afterwards If the sensor functions according to the above description carefully remove the black tape with the white seal and the protective plastic tube before making measurements MEASUREMENTS MOUNTING OF THE ELECTRODE TEMPERATURE To mount the electrode for measurements unscrew the screw Closely monitor breaking the white paper seal When the screw is loose the sensor the temperature because the sensor can be drawn from the protective tube and used normally signal will vary Although the Unisense micro electrodes are made of glass the with temperature tip is flexible and can bend slightly around physical obstacles However larg
5. tolerate up to 20 minutes of exposure to air IMPORTANT Construction of the electrode with an internal reference involves the creation of a liquid junction approximately 3cm from the electrode tip During measurements this liquid junction must be submerged in the medium in order to complete the measurement circuit REFERENCES e K hl M Revsbech 2001 Biogeochemical microsensors for boundary layer studies In The Benthic boundary layer Boubreau B P Jorgensen B B eds New York Oxford University Press pp 180 210 Revsbech P and B Jorgensen 1986 Micro electrodes Their Use in Microbial Ecology 293 352 In C Marshall ed Advances in Microbial Ecology vol 9 Plenum New York Thomas 1978 lon selective intracellular microelectrodes how to make them and use them Academic Press London TROUBLE SHOOTING Problem Possible cause Solution Problem Possible cause 1 Solution Possible cause 2 Solution Possible cause 3 Solution Possible cause 4 Solution Possible cause 5 The sensitivity of the pH micro electrode is low the signal is stable and does not change with pH The pH sensitive tip has suffered physical damage and is most likely broken Replace the electrode Sensitivity of the pH micro electrode is low or the signal is unstable The pH meter is not suitable for pH micro electrodes Change the pH meter to one with a su
6. 00 200 glass electrode and a REF321 filled with 3M KCI will give a zero pH of approx pH 7 25 23 dy UNISENSE UNISENSE DENMARK www unisense com infogunisense com
7. KCI 3M e f Radiometer Vanalytical REF321 Reference Electrode Introduction The 21 is a general purpose Ag AgCl reference electrode fitted with a screw cap Preparation for measurement 1 Remove the protection cap from the electrode and any seals covering the filling hole 2 Before starting a measurement remove the clip which closes the electrode filling hole Remember to replace the clip at the end of measurements 3 Check the level of the filling solution It should be approximately 0 5 cm below the filling hole If necessary refill with KCleAg 3 M KCI Solution saturated with AgCl If desired the concentration of can be changed However it is advisable to use a high concentration Remember always to saturate the solution with AgCl For nonaqueous applications such as measurements in acetic acid Empty the electrode and fill it up again with a saturated KCI solution in acetic acid Saturate the solution with AgCI 4 In order to remove air bubbles trapped inside the electrode shake the electrode holding it at its head with the porous plug down Maintenance 1 Electrode contamination is a major cause of faulty measurements 2 The electrode should be rinsed with distilled water after measurements 3 Check frequently the level of filling solution 4 In case of deposits which cover the electrode clean the electrode with e a solution of acid 0 1M 0 1 HNO minera
8. VA UNISENSE pH AND REFERENCE ELECTRODE USER MANUAL Uni ca Wb AND REFERENCE ELECTRODE MANUAL Copyright 2014 Unisense A S Version December 2014 pH AND REFERENCE ELECTRODE MANUAL UNISENSE A S 5 SUPPORT ORDERING AND CONTACT INFORMATION OVERVIEW zi cag l dor ada aua PH ELECTRODE REFERENCE ELECTRODE GETTING STARTED sits iore DOE ER RUD RC RE Kad UNPACKING A NEW PH ELECTRODE UNPACKING A NEW REFERENCE ELECTRODE CONNECTING THE ELECTRODES CALIBRATION MEASUREMENTS seursai tn rapere RR Ra MOUNTING OF THE ELECTRODE pH COMBINATION SPECIAL CAUTIONS FOR COMBINATION ELECTRODES ADVANCED PH ELECTRODES rere RI RS Rr RET CER STORAGE AND STORAGE CLEANING THE ELECTRODE REFERENCES TROUBLE SHOOTING sister ai MANUAL siii eee WARRANTY AND LIABILITY NOTICE PURCHASER This product is for research use only Not for use in human diagnostic or therapeutic procedures WARNING Microsensors have very pointed tips and must be handled with care to avoid personal injury and only by trained personnel Unisense A S recommends users to attend instruction courses to ensure proper use of the products WARRANTY AND LIABILITY The pH electrode is covered by a 90 days lim
9. e obstacles like stones or coarse lateral movements of the electrode when the tip is in contact with a solid substrate may cause the tip to break Also due to the small size of the microsensor tip and to the steepness of gradients in many environments even a displacement of the electrode tip of few microns may change its environment Therefore measurements should be performed only in a stabilized set up fixed on a sturdy table free of moving or vibrating devices We recommend the Unisense lab stand LS18 and the Unisense micromanipulator MM 33 MM33 2 double for laboratory use For in situ use we recommend our in situ stand 1519 and a micromanipulator ELECTRICAL NOISE The electrical current generated by the high impedance micro electrode is very small Although the Unisense pH micro electrodes are very resistant to electrical noise from the environment electrical fields may interfere with the electrode signal Therefore we recommend that unnecessary electrical or mechanical equipment is switched off and the electrode or wires are not touched during operation 13 COMBINATION ELECTRODE For a limited number of pH electrodes we offer combination electrodes with internal reference as indicated by the product number ending with a eg pH 500C These are made for selected applications like small volume measurements or small space applications measuring inside an applied electrical field or crude profiling But for most applicat
10. fficiently high impedance gt 10 Ohm e g Unisense pH mV Meter The reference electrode is not properly connected or is malfunctioning Connect the reference electrode and make sure that it is properly submerged in the same solution as the pH electrode Alternatively repair or change the reference electrode Insoluble compounds have been deposited on the pH sensitive tip Rinse the tip with ethanol rinse with 0 01 M HCI and rinse with distilled water Air bubbles present at the tip of a micro reference electrode Remove bubbles with a fine brush and avoid entrapment of bubbles Contamination of micro reference half cell with soluble compound e g sulfide visible dark band approaching the half cell through the gel TROUBLE SHOOTING Solution Replace reference electrode Possible cause 6 Insoluble compounds deposited at the gel water junction of the micro reference electrode Solution Replace reference electrode If you encounter other problems and need scientific technical assistance please contact sales unisense com for online support we will answer you within one workday 19 MANUAL FOR REF RM 20 REF321 Reference Electrode Electrode de R f rence 12 Filling hole Orifice de remplissage Filling solution Solution de remplissage la Ag AgCl wire Fil de Ag AgCl Porous plug Poreux 8mm Protection cap filled with 3M KCI Capuchon de protection rempli de
11. ions we recommend to use our standard pH electrode with external reference electrode Please test calibrate and measure as described for standard pH electrodes but with attention to the special causes for pH combination electrodes SPECIAL CAUTIONS FOR PH COMBINATION ELECTRODES Reference electrode is built in do not use external reference electrode as well Electrode must be stored in 2M KCI solution Do not allow electrode to dry out only allow short time less than minutes exposure to air Reference electrode is situated near the electrode tip about 1mm away thus minimum immersion depth is 1mm Through the 10 um opening for the reference electrode small amounts of KCI will diffuse out and give a small contamination of the sample Reference electrolyte cannot be refilled but the included electrolyte is expected to last for the lifetime of the electrode ADVANCED ELECTRODES Unisense can construct pH electrodes for customer requested applications at an additional cost Unisense provides several options for customizations e g tip size response time and stirring sensitivity and adaptations e g mounting in needle or flow through cell making accurate measurements possible for even more applications Please visit our website for more information 15 STORAGE AND MAINTENANCE STORAGE PH ELECTRODE The pH electrode should be stored upright in the protective tube Always keep the tip moist
12. ited warranty Microsensors are a consumable Unisense will only replace dysfunctional sensors if they have been tested according with the instructions in the manual within 14 days of receipt of the sensor s The warranty does not include repair or replacement necessitated by accident neglect misuse unauthorized repair or modification of the product In no event will Unisense A S be liable for any direct indirect consequential or incidental damages including lost profits or for any claim by any third party arising out of the use the results of use or the inability to use this product Unisense mechanical and electronic laboratory instruments must only be used under normal laboratory conditions in a dry and clean environment Unisense assumes no liability for damages on laboratory instruments due to unintended field use or exposure to dust humidity or corrosive environments REPAIR OR ADJUSTMENT Sensors and electrodes cannot be repaired Equipment that is not covered by the warranty will if possible be repaired by Unisense A S with appropriate charges paid by the customer In case of return of equipment please contact us for return authorization For further information please see the document General Terms of Sale and Delivery of Unisense A S as well as the manuals for the respective products CONGRATULATIONS WITH YOUR NEW PRODUCT SUPPORT ORDERING AND CONTACT INFORMATION This microelectrode is a miniaturized conventiona
13. l pH electrode based on selective diffusion of protons through pH glass The small tip size facilitates rapid and precise pH measurements in a broad variaty of micro environments If you wish to order additional products or if you encounter any problems and need scientific technical assistance please do not hesitate to contact our sales and support team We will respond to your inquiry within one working day E mail sales unisense com Unisense A S Tueager 1 DK 8200 Aarhus N Denmark Tel 45 8944 9500 Fax 45 8944 9549 Further documentation and support is available at our website www unisense com REPLACEMENT OF SENSORS Unisense will replace sensors that have been damaged during shipment provided that The sensors were tested immediately upon receipt in accordance with the delivery note and the manual The seal is still intact The sensors are returned to Unisense for inspection within two weeks The sensors are correctly packed for return to Unisense in accordance with the note included in the sensor box RECOMMENDED METERS FOR SENSORS One channel meter pH mV Meter Multi channel meters for pH Microsensor Multimeter OVERVIEW This manual covers all Unisense and reference electrodes WARNING Unisense sensors PH ELECTRODE are neither The Unisense pH micro electrode is miniaturized glass intended nor electrode designed for research applications within physiology approved for use bio
14. l salt deposits etc e KS400 Pepsin in Solution or RENOVOeX Xtra Strong Cleaning Solution protein deposits milk cheese serums Duration of treatment 1 to 2 hrs 21 22 5410 Thiourea Solution for porous plugs contaminated with sulphides or blocked by an AgCI precipitate Duration of treatment a few hours until the porous plug turns white RENOVOeN Normal Cleaning Solution greasy or oily deposits The porous plug of the electrode can be cleaned using a fine abrasive paper Storage Between measurements leave the REF321 in KS110 3M KCI Solution Overnight or longer seal the filling hole with paraffin film or with the electrode clip and fit back in place the protection cap filled with the KS110 3M KCI Solution Accessories KS110 KCI Solution 500 C20C320 KCleAg Solution S21M004 saturated with AgCI 100 ORENOVO N S16M001 Normal Cleaning Solution 250 ml 516 002 Xtra Strong Cleaning Solution 250 ml KS400 Pepsin Solution 250 ml C20C370 KS410 Thiourea Solution 250 ml C20C380 CL111 Electrode cable with banana plug A94L111 Specifications Reference potential when filled with in mV Temperature 0 10 20 25 30 40 std hydrogen elec 225 219 212 208 204 196 vs sat Hg Hg Cl elec 35 36 36 36 37 38 Temperature range O to 80 C Note an electrode chain comprising pHG301 or XG1
15. technology environmental sciences and related areas on humans With tip diameters down to 10 microns the Unisense pH micro electrode allows measurements of pH with a very high spatial resolution The Unisense pH micro electrode can be used for measurements in salinities from zero to full ocean strength MEASUREMENT PRINCIPLE The electric potential reflects the acidity of the solution Thus the pH micro electrode must be used in combination with a reference electrode internal or external and connected to a high impedance 10 Ohm millivolt meter When the electrode tip is immersed in an aqueous solution and connected via a millivolt meter to a reference electrode immersed in the same solution the pH electrode tip will develop an electric potential relative to the reference electrode reflecting the pH of the solution REFERENCE ELECTRODE The Unisense reference electrode is a simple open ended Ag AgCl electrode with a gel stabilized electrolyte The reference electrode is used to establish a reference potential against the pH micro electrode For laboratory use Unisense provides a macro reference electrode from Radiometer Analytical please see separate manual in the back of this booklet Our micro sized reference electrodes are glass electrodes manufactured at Unisense For situ use Unisense manufactures a pressure compensated macro electrode Unisense offers selected versions of pH electrodes with internal reference
Download Pdf Manuals
Related Search