Hanna Instruments

The HI-2221-02 is a pH bench top meter features our exclusive Calibration Check diagnostics for both pH electrodes and buffer solutions during calibration. This instrument compares the characteristics of the pH electrode from one calibration to the next. In the case of large variances in the electrode condition, it alerts the user that the electrode needs to be properly cleaned prior to calibration and measuring.

The second feature is to detect if the calibration buffer solution is contaminated. After calibration, the probe condition is evaluated and an indicator is displayed informing the user of the overall pH electrode status.

This instrument can measure using ORP electrodes (pH channel input), due to its capability to measure mV with a resolution up to 0.1 mV.

A properly manufactured and maintained pH electrode will retain its measuring integrity for a long time. As a result of many factors such as age, poor maintenance or improper handling, any electrode in time will lose its integrity. The most common cause for pH measurement inaccuracies is an unclean or improperly cleaned electrode. This is very important to note, because during calibration, the instrument assumes that the electrode is clean and that the standardisation curve created during the calibration process will remain a valid reference until the next calibration.