Cleaning and Maintenance Procedure of pH electrodes

Cleaning and Maintenance Procedure of pH electrodes

Conditions to avoid

Maintenance and care with pH electrodes Reference ORP Conductivity

PH Electrode Cleaning reference

ORP Electrode Cleaning

Conductivity Cell Cleaning




Conditions to avoid 
 

  • Whenever you remove the vial with the storage solution from your sensor, completely unscrew the cap from the sensor;
     
  • Be very careful when handling your analytical sensor, it is constructed of glass and has parts, such as the bulb, that are very sensitive to mechanical action. A knock on the bottom of a Becker cup, for example, is enough to damage the piece;
     
  • Never scrape or sand the surface of the glass (bulb) of the electrode;
     
  • Do not leave your sensor (pH, ORP or conductivity) out of the storage solution for longer than 6 hours. This may compromise the speed of response of the part or even render it unusable;
     
  • Never store your pH or ORP sensor in deionized water. Respect the recommendation of storage solution for pH, reference and ORP sensor type; Only conductivity cells should be packed in deionized water;
     
  • Inlays on the surface of the glass (bulb) or its reference system (ceramic joints) will prevent a correct reading;
     
  • Avoid extreme conditions whenever possible, and be aware of the specific usage limitations of each sensor model you are using. High temperatures, as well as constant measurements in strong acids or caustic solutions, shorten the life of the sensor;
     
  • Never expose the electrode to temperatures below -12 ° C.
     




Maintenance and care with pH electrodes Reference ORP Conductivity
 

  • Analytical sensors typically require periodic maintenance to ensure the quality of their readings and extend their life. 
     
  • Keeping the electrode, when out of use, immersed in the packaging solution is the main one. Here are some indications:
    • • pH, reference or ORP sensors with internal KCl electrolyte 3 mol / AgCl - 3 mol KCL packing solution ( SSE02 ).
       
    • • pH or reference sensors with KNO³ internal electrolyte - KNO³ packaging solution ( SSE05 ).
       
    • • pH sensors for alcohol, with internal electrolyte of LiCl 2 mol. - 2 mol of LiCl packaging solution in ethanol ( SSE01 ).
       
    • • Conductivity cells, for all constants - use deionized water.
       
  • Keep the internal electrolyte level always near the fill hole. 
     
  • Shielded sensors do not require filling of the internal electrolyte. 
     
  • Always use the internal electrolyte recommended by the manufacturer. 
     
  • After use, rinse the sensor with deionized water to remove any scale that might deposit on it. 
     
  • Remove the internal electrolyte whenever the sensor has a slope lower than 95%, or when it is used in very aggressive or contaminated systems.




PH Electrode Cleaning Reference
 

  • Salt deposit: Dissolve the deposits by immersing the electrode in clean water for 10 to 15 minutes.
     
  • Oils and greases: Carefully wash the electrode bulb with biodegradable neutral pH detergent and water until all grease is removed.
     
  • Reference joint clogged by salt drying: heat a 3 mol KCL solution (SSE02). up to 50 ° C and keep the sensor immersed for up to 10 minutes. Let the electrode cool naturally.
     
  • Contaminated reference junction: use Thiourea solution (SSL02). Let the electrode immersed in the solution for 30 minutes.
     
  • Protein Deposits: use Pepsin solution (SSL01). Leave the electrode in the solution for a maximum of 5 to 10 minutes.
     
  • Slope less than 95%: for "rechargeable" electrodes - Remove the internal electrolyte through the refill hole, with the aid of a syringe. Rinse the part internally with deionized water 3 times. With the internal reference system clean, fill the sensor with a new internal electrolyte (SSE01, SSE02 or SSE05). This procedure should also be repeated 3 times before use. 
     
  • After each of the procedures listed above, thoroughly rinse the piece with deionized water, dry it carefully using absorbent paper towel and leave the electrode resting in its packaging solution for 24 hours.
     
  • The above procedures may not be sufficient to restore the measurement quality of a sensor and such inefficiency is not considered a warranty defect.
     




ORP Electrode Cleaning
 

  • ORP electrode bulb (metal rod): can be gently wiped with wet paper, dry silicon or carbide, ferric oxide, emery cloth, iron oxide or wool from fine metal fibers.
     
  • Salt deposit: Dissolve the deposits by immersing the electrode in clean water for 10 to 15 minutes.
     
  • Oils and greases: Carefully wash the electrode bulb with biodegradable neutral pH detergent and water until all grease is removed.
     
  • Reference joint clogged by salt drying: heat a 3 mol KCL solution (SSE02). Up to 50 ° C and keep the sensor immersed for up to 10 minutes. Let the electrode cool naturally.
     
  • Contaminated reference junction: use Thiourea solution (SSL02). Let the electrode immersed in the solution for 30 minutes.
     
  • Deviation above + 15mV: for "rechargeable" electrodes - Remove the internal electrolyte through the refill hole with the aid of a syringe. Rinse the part internally with deionized water 3 times. With the internal reference system clean, fill the sensor with a new internal electrolyte (SSE01). This procedure should also be repeated 3 times before use.
     
  • After each of the procedures listed above, thoroughly rinse the piece with deionized water, dry it carefully using absorbent paper towel and leave the electrode resting in its packaging solution for 24 hours.
     
  • The above procedures may not be sufficient to restore the measurement quality of a sensor and such inefficiency is not considered a warranty defect.
     




Conductivity Cell Cleaning
 

  • Deionized water or biodegradable neutral detergents may be used.
     
  • For more specific cleaning, a mixture of one part by volume of isopropyl alcohol, one part ethyl ether and one 0.1 M HCl part may be used. After cleaning, rinse the cell thoroughly with deionized water.
     
  • More severe procedures provide for the removal of the platinum black film, with the application of water to the electrode, or electrolysis in HCL.
     
  • For cells without or with black platinum removed, a new platinization is necessary.
     
  • Platinization procedure:
    • • Platinization solution: Dissolve 1.0g of chloroplatinic acid PA (H2PtCl6 * 6H2O) and 0.012 g of lead acetate PA (CH3COO2) in 100 ml of deionized water. This solution can be reused several times
       
    • • Immerse the conductivity cell in this solution and connect one of the wires to the negative pole and the other to the positive of a 1.5 V dry cell. Keep immersed until one of the platinum plates is completely platinized. Reverse the poles and perform the procedure again. Rinse the electrodes with deionized water.
       
  • After each of the above procedures rinse the piece with deionized water in abundance, dry it carefully using absorbent paper towel.
     
  • The above procedures may not be sufficient to restore the measurement quality of a sensor and such inefficiency is not considered a warranty defect.
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