Use PH meter: he from the host, the composite electrodes, there are four knobs on the host, they are: selection, temperature, slope and positioning knob. Installed equipment, electrodes, open the power switch on the rear of the instrument, a half-hour warm-up. Prior to measurement, the first PH meter calibration, we used two position calibration method, the specific steps are as follows: Select knob to adjust the PH gear; measuring the temperature of the test solution, with the thermometer reading, for example, 25oC. Knob to adjust the temperature measurements 25oC. Knob to adjust the slope of the maximum. Open the electrode casing, washed with distilled water electrode head with absorbent paper carefully dry electrode head, the composite electrode into the standard mix of phosphate buffer solution, and the solution of the head electrode submerged glass balls, gently shake ph meter principle, until the reading is stable, adjust the positioning knob so that the display is a standard PH value of the solution at 25oC 6.86. Remove the electrode, wash, dry and put it into a standard potassium hydrogen phthalate buffer solution, shake, until the reading is stable, adjust the slope of the knob, the display is a standard PH value of the solution at 25oC 4.00. Remove the electrode, wash, dry, put again the standard mixed phosphate buffer solution, shake ph meter, until the reading is stable, adjust the positioning knob so that the display standard PH value is 25oC 6.86. Remove the electrode, wash, dry and put it into a buffer solution of potassium hydrogen phthalate, shake, until the reading is stable ph meter structure, and then adjust the slope of the knob, so standard PH value displayed is 25oC 4.00. Remove the electrode, wash, dry. Repeat calibration until the measured value and the standard values ??of the two standard solution PH basic line so far. After the calibration process, enter the measurement mode. The composite electrode into the beaker containing the test solution, and gently shake until the reading is stable, record the reading. After the completion of the test, remove the solution, rinsed with distilled water electrode, dry, put the casing, turn off the power, ending the experiment. PH / orp meter standard buffer preparation and preservation ⒈pH standard materials should be stored in a dry place, it will happen as deliquescence mixed phosphate pH standard material humidity in the air, once deliquescence occurs, pH standard material that can not be used . ⒉ preparation of pH using a secondary standard solution should be distilled or deionized water. If it is used in 0.1 pH meter ph meter maintenance methods, you can use an ordinary distilled water. ⒊ preparation of pH standard solutions should be used to dilute a small beaker to reduce the dip in the walls of the beaker pH standard solution. PH standard substance stored in plastic bags or other containers, in addition to be clean down outside, further washed several times with distilled water, then poured into pH standard solution prepared in order to ensure accurate pH standard solution prepared. ⒋ preparation of a good standard buffer solution can be stored for 2-3 months in general, if there is muddy, moldy or when precipitation and other phenomena, can not continue to use. ⒌ standard alkaline solution should be packed in polyethylene bottles sealed. Prevent carbonate formation after carbon dioxide entering the standard solution, lowering its pH. Use ph meter, ph meter, one hundred to one hundred technology provided by Changzhou Technology Limited. Changzhou Best Technology Limited (www.czbckj.com) strong, credible, in Changzhou, Jiangsu chemical instrumentation industry has accumulated a large number of loyal customers. The company better work attitude and continuous improvement will lead one hundred innovative ideas into technology and you hand into the brilliant, for a better future!