The built-in microchip stores sensor type, serial number and calibration information including date, time, offset, slope, probe condition and buffers used. This information is automatically retrieved by edge®once the electrode is plugged in. The ability to transfer information allows for hot swapping of probes without having to recalibrate. All pH measurements are performed within the electrode and transferred digitally to the meter. This overcomes any noise issues associated with the traditional high impedance analog measuring system. Electrical noise can be generated from a built in temperature sensor and while working in a humid environment.
Spherical Glass Tip
The spherical shaped tip design allows for a wide area of contact with the sample. This permits a faster electrode response with a higher degree of stability. The tip uses a glass formulation that has a resistance of approximately 100 megaohms. This means that measuring conditions are optimal around ambient temperatures. Use of high or low temperature glass around ambient temperatures would not be optimal due to a long response time or a shortened lifespan of the electrode.
Double Junction Reference
A double junction electrode has an internal compartment surrounding the reference wire. Silver ions are present in the electrolyte of the internal compartment, which houses the Ag/AgCl reference wire; the electrolyte outside this compartment is silver free. The double junction design means that virtually no silver from the electrode enters the sample. This design allows measurement in applications where silver ions in the sample are undesirable or silver precipitates on the junction are likely to form.
PEI Electrode Body
The PEI (polyetherimide) electrode body is suitable for a wide range of applications and excels in field measurements due to its durability. The shielding around the spherical glass tip minimizes breakage due to accidental bumping or dropping of the electrode. The PEI plastic is a high quality plastic that is chemically resistant to many harsh chemicals.
The HI12301 integrates a matching pin into the electrode and is part of the Hanna Instruments Sensor Check™ feature. The matching pin checks the impedance across the indicating and reference electrodes. This allows the edge meter to alert the user in the event that the glass of the indicating pH electrode is cracked and the condition of the reference junction.
Built-In Temperature Sensor
HI12301 features a built-in thermistor temperature sensor that is in the tip of the indicating pH electrode. A thermistor temperature sensor provides for a high accuracy temperature reading and should be as close as possible to the indicating pH electrode in order to compensate for the effect that temperature has on the membrane potential. By having an accurate reading it is possible to provide an accurate temperature compensated reading.