The operation steps of the two-point calibration method to determine the pH value of the solution
Choose two standard buffers: one is pH7 standard buffer, the second is pH9 standard buffer or pH4 standard buffer. First use the pH7 standard buffer solution to position the electrometer, and then select the second standard buffer solution according to the acidity and alkalinity of the solution to be tested. If the solution to be tested is acidic, use a pH4 standard buffer; if the solution to be tested is alkaline, use a pH9 standard buffer. If it is a manually adjusted pH meter, it should be operated several times between the two standard buffer solutions until it is no longer necessary to adjust its zero point and positioning (slope) knobs, and the pH meter can accurately display the pH values of the two standard buffer solutions. Then the calibration process ends. Thereafter, the zero and positioning knobs should not be moved during the measurement.
