ISEs typically utilise one of 4 primary sensor types:
Polymer Membrane – This common sensor design incorporates ionophores or other ion exchange agents that are specific to the ion of interest, into an inert matrix such as PVC. A millivolt potential develops at the surface of the membrane and is correlated to the ion concentration. This sensor type is accurate but less durable than some others. Sensors of this type include: Ca2+, BF4- , NO3 – , K+, and Surfactant.
Solid State – These sensors utilise relatively insoluble inorganic salts within a hard pellet or crystalline matrix that allows the detection of specific ion activity. These sensors are both accurate and one of the longest lasting ISE sensor types. They may need to be buffed on occasion to restore performance. Sensors of this type include: Br- , Cd2+, Cl- , CN- , F- , I- , Pb2+, S2 – , Ag2+, and SCN
Gas Sensing – With a gas permeable membrane, an internal buffer solution, and the use of ionic strength adjustors, these sensors are an accurate method to detect ions like NH4+, CO2, NOx and others.
Glass Membrane – Like a pH sensor, these ISEs use a special glass formula to be selective for a specific ion. Na+ is a common parameter for this type of ISE.
Our ISEs (with exception) with the proper Reference Filling Solution, Ionic Strength Adjustor, Calibration Solution, and an Instruction Sheet so the analyst has everything they need to begin their measurements.
To address the design requirements of ion-selective sensor, as well as the needs of analysts, ASI has primary types of combination ISEs:
35 Series – A few ions are only sensed in the gas form. This gas-sensing ISE has replaceable membranes, a refillable inner body and provides an accurate measuring system.
SPECIFICATIONS
Sensor: Replaceable membranes
Reference: Refillable Inner body
Construction: ABS
Parameters: NH3, CO2 , NOX
Ordering Information:
CO35-0001 Carbon Dioxide (carbonate)
aci-ise-spec-sheet7