How to use a pH meter correctly, how to calibrate and use a pH meter

How to use an acidity meter (pH meter).

The method of pH meter calibration and use is as follows:

Calibration: Immerse the test pen electrode in mixed phosphate standard buffer at pH and shake gently; Adjust the calibration potentiometer with a small screwdriver until the displayed value matches the pH value of the standard buffer solution at ambient temperature; The electrode is inserted into a standard buffer solution of potassium phosphate dicarboxylate or borax; The displayed value should be within the allowable error range compared to the pH value of the buffer solution.

How to use: 1. Open the back cover and insert a battery.

2. Install the composite glass electrode.

3. Turn on the power switch, and then hit the pH measurement file.

4. Measure the temperature of the standard liquid with a thermometer, and then adjust the pH meter temperature compensation knob to the measured temperature value.

5. Rinse the composite electrode with deionized water and wipe it dry with filter paper.

6. Pour 2 5ml of the standard solution into the plastic beaker that has been washed and dried with water, pour it out after washing the beaker and the compound electrode, then add the standard solution to the plastic beaker, insert the compound electrode into the solution, use the instrument to position the knob, adjust to the reading, until it is stable.

7. Wash the composite electrode with deionized water, wipe it dry with filter paper, measure the temperature of the solution with a thermometer, and adjust the temperature compensation knob of the instrument to the measured temperature value.

8. Pour 2 5ml of the standard solution into another plastic beaker, pour it out after washing the beaker and the composite electrode, then add the standard solution, insert the composite electrode into the solution, and adjust it to the slope knob after the reading is stable. It should be noted that after the slope button is adjusted, it must not be moved again.

9. Use a thermometer to measure the temperature of the liquid to be measured, and adjust the temperature compensation of the instrument to the measured temperature.

10. Insert the compound electrode into the solution to be measured, and read the pH value, which is the pH value of the solution to be measured.

pH Meter:

A pH meter is an instrument used to determine the pH value of a solution. The pH meter works using the principle of galvanic cells, and the electromotive force between the two electrodes of galvanic cells is based on Nernstein's law, which is related to both the properties of the electrodes themselves and the concentration of hydrogen ions in solution. There is a correspondence between the electromotive force of the galvanic cell and the hydrogen ion concentration, and the negative logarithm of the hydrogen ion concentration is the pH value.

pH meter is a common analytical instrument, which is widely used in agriculture, environmental protection and industry. Soil pH is one of the most important basic properties of soil. Factors such as the temperature and ionic strength of the solution to be measured should be considered during pH measurement.

The use of pH meter can better control chemical reactions, achieve the purpose of improving productivity and product quality, and safe production. The pH measurement system with automatic recording also provides evidence of litigation against pollution pollution. Some batch production processes (e.g., some fertilizer production, food processing processes) can be changed to continuous production using a pH meter.

In modern industry, more pH meters are used than other types of continuous analytical instruments combined. A pH meter is required in almost all production sectors that require water.

1. Plug in the power supply and turn on the power switch, as shown in the figure below.

2. Take out the detection electrode and clean it with distilled water, as shown in the figure below 3. First calibrate it with the calibration solution of pH, as shown in the figure below.

4. Calibrate with a calibration solution with pH value (need to be cleaned with distilled water before calibration), and the slope should be greater than or equal to 95% after calibration

5. Check the pH value (you need to clean it with distilled water before testing) 6. Clean the electrode after the test, put the electrode back in place, and turn off the power.

There are many types of pH meters due to the different designs of electric meters, and their operation steps are different, so the operation of pH meters should be carried out correctly in strict accordance with its instruction manual. In practice, calibration is an important step in the operation of a pH meter. The data in Table 1 shows the measured values of pH meters that have passed the metrological verification at the same level when they are not calibrated and after calibration, from which the importance of calibration can be seen.

The calibration method adopts a two-point calibration method, that is, two standard buffers are selected: one is pH7 standard buffer, and the second is pH9 standard buffer or pH4 standard buffer. The electrometer was first positioned with pH7 standard buffer, and then a second standard buffer was selected according to the acidity and alkalinity of the solution to be measured.

How to use an acidity meter (pH meter).

The usage method of different manufacturers is not completely consistent.

General steps: connect the instrument and electrode, clean the electrode, calibrate the electrode, clean the electrode, measure the sample, record the data, and clean the electrode.

What kind of PH meter, which one.

Calibration of the pH meter.

Flip the "PH-MV" switch to the PH position.

Turn on the power and turn on the indicator light at the beginning and warm up for 30 minutes.

Remove the small beaker with distilled water and gently blot off excess water beads from the glass electrode with filter paper. Fill a small beaker with a standard buffer solution of choice, known pH. Immerse the electrodes.

Take care to immerse the beads at the top of the glass electrode and the capillary pores of the calomel electrode in the solution. Gently shake the small beaker to homogenize the solution that the electrode is in contact with.

Depending on the pH of the standard buffer, screw the range switch to 0 7 or 7 14.

Adjust the temperature control knob so that the temperature indicated by the knob is the same as the room temperature.

Adjust the zero point so that the pointer is at pH7.

Gently press or turn the reading switch slightly to make the switch jam. Adjust the positioning knob so that the pointer is pointing exactly at the pH of the standard buffer. Release the reading switch and repeat until the value is stable.

After calibration, do not turn the positioning knob again, otherwise it will need to be recalibrated. Remove the small beaker of the standard solution and rinse the electrode with distilled water.

Measurement of the pH meter.

Blot the excess water droplets on the electrode or rinse it twice with the solution to be measured, then immerse the electrode in the solution to be measured, and gently turn or shake the small beaker so that the solution evenly touches the electrode.

The temperature of the solution to be measured should be the same as that of the standard buffer solution.

Adjust the zero position, press the reading switch, and the value pointed by the pointer is the pH of the liquid to be measured. If the pointer reading exceeds the scale when measuring within the range pH0 7, the range switch should be placed at pH7 14 for re-measurement.

After the measurement is completed, after releasing the reading switch, the pointer must point at pH7, otherwise it will be readjusted.

Turn off the power, rinse the electrodes, and soak as described above.

METTLER TOLEDO sevencompact?The pH meters are versatile, easy to use, and rugged. This benchtop pH meter is suitable for a variety of industries, such as pharmaceutical, food and beverage, and chemical.

Optimized measurement parameters ensure good performance in all pH and conductivity measurements.

1. Plug in the power supply and turn on the power switch. 2. Take out the detection electrode and clean it with distilled water. 3. First calibrate with a calibration solution with pH value.

4. Calibrate with a calibration solution with pH value (need to be cleaned with distilled water before calibration), and the slope after calibration should be greater than or equal to 95%. 5. Test the pH value (need to be cleaned with distilled water before the test). 6. After the test, clean the electrode, put it back in place, and turn off the power.

Extended data: There are a number of ways to measure the pH of a solution: if a pH indicator is added to the solution to be measured, different numbers or indicators will change color depending on the pH value.

For example: 1. Drip the acidic solution into the litmus solution will make the litmus solution red; Drip the alkaline solution into the litmus solution, and the litmus solution will turn blue (the litmus solution will not change color when it encounters a neutral liquid). By studying the indicators, it is possible to determine the range of pH values.

2. Dropping colorless phenolphthalein solution into an acidic or neutral solution will not change the color; The colorless phenolphthalein solution was dropped into the alkaline solution, and the solution turned red. Note: When adding a pH indicator to the colored solution to be measured, the pH indicator that can produce significant color difference should be selected.

When titrating, an accurate pH standard can be made. Use pH test strips, including general-purpose test strips and precision test strips. Use a glass rod to dip a little solution on the test strip, and then compare the pH value of the solution with the color chart according to the color change of the test strip.

The above table is equivalent to a colorimetric chart. Use a pH meter, which is an instrument that measures the pH of a solution. It measures the pH of a solution through a pH-selective electrode, such as a glass electrode.

The acidity meter can be accurate to two decimal places.