3M MP220 Installation Guide - Page 5

Operating Hints n Remove the wetting cap from the end of the electrode and the rubber cap from the fill hole (if fitted) before using the electrode. n Calibrate using buffers with values that bracket that of the sample. With a new pH electrode, or after maintenance, we recommend you use a buffer close to pH 7 for the first calibration point. n For greatest accuracy, buffers and samples should be at the same temperature. n Do not use solutions after the expiry date. n When transferring the electrode from one solution to another, rinse it with distilled water and blot dry with tissue paper - do not wipe the electrode as this may cause polarization and slow response. n When you select the calibration buffers (Program Menu), set the buffer you will use most frequently for 1-point calibrations as cal 1 and the one you will use most frequently for the second calibration point as cal 2, and for the MP225, the one you will use most frequently for the third calibration point as cal 3. 5