Model 121pH Electrode
Price: $79.00
pH Probe
MicroLab’s pH probe is a rugged industrial combination electrode. This
maintenance-free probe measures pH 0-14 pH units, 0 to 80 °C.
SKU: 121
Description:
This sensor is a standard double-junction industrial pH probe. The body of the probe is rugged Ultem®(polyetherimide) and is practically unbreakable. This “combination” pH probe provides both parts of an electrochemical cell which is sensitive to the hydrogen ion concentration of the solution in which it is immersed.
The probe consists of two concentric cylinders. The outer cylinder contains a sealed, gel-filled silver/silver chloride reference electrode.
The inner cylinder ends in a pH-sensitive glass bulb (the other half of the pH-sensitive electrochemical cell). This glass is extremely thin and must be saturated with water to permit movement of hydrogen ions from the solution into the liquid in the bulb. The pH sensing bulb should not be touched and is protected by serrated teeth in the plastic probe body. It is kept moist during storage by an included plastic storage bottle filled with 3.5 M KCl solution.
The number of electrons the probe can provide to a measuring instrument is limited to the very small number of hydrogen ions that can move through the porous glass of the pH-sensing bulb. Because so few electrons are available, the cable and BNC plug are extremely well insulated. If the connector is contaminated with salts – for example by rinsing it with tap water – pH readings will degrade. The inside of the BNC connector should be periodically cleaned with a wash bottle containing alcohol and deionized water.
Typical Experiments:
This pH probe is ideal for experiments involving:
- Determination of the pH of common household substances
- Creating acid-base titration curves and determining end points
Specifications:
pH Probe
| Range | 0 to 14 pH units, 0- 80OC | Sensor dimension | 150 mm long, 12 mm diameter |
| Resolution | With factory calibration ± 0.2 pH. Accuracy can be improved to ± 0.01 pH by rapid threepoint buffer calibration with MicroLab software. | Cable length | 91 cm |
| Resolution | ± 0.001 pH units | Connector | Standard Industrial BNC Connector |
Save this content for future expansion of the pH probe content:
The probe consists of two concentric cylinders. The outer cylinder contains a sealed, gel-filled silver/silver chloride reference electrode. The silver wire, visible from the outside of the probe, connects to the shield and outer conductor of the sensor cable and connector. Porous fibers (called junctions) visible at the bottom of the probe transfer ions between the internal reference electrode and the sample solution. A double junction electrode has an extra porous barrier which prevents contaminants in the solution from reacting with the silver that is present in the
reference electrode, thus plugging the junction.
The inner cylinder ends in a pH-sensitive glass bulb which contacts the solution. This glass is very thin and must be saturated with water to permit movement of hydrogen ions from the solution into the liquid in the bulb. This half-cell is contacted by a wire, also visible, that connects to the center conductor of the cable and BNC connector. The thin pH sensing bulb is protected by serrated teeth in the plastic probe body and should not be touched. It is kept moist during storage by an included plastic storage bottle filled with 3.5 M KCl solution.
The number of electrons that can be provided to a measuring instrument is limited to the very small number of hydrogen ions that can move through the porous glass of the pH-sensing bulb. Because so few electrons are available, the cable and BNC plug are extremely well insulated. The BNC connector should be periodically cleaned with a wash bottle containing alcohol and deionized water. If the connector is contaminated with salts, pH readings will degrade.
