Chemical Metrology I: Calibration of a pH meter and Quality Control
DOI:
https://doi.org/10.5377/universitas.v1i1.1627Keywords:
chemical metrology, PH meter calibration, Control charts in pH measurement, Quality control in pH measurement.Abstract
The main objective of this work is to establish a reliable methodology for the calibration of a pH meter using a pH calibrator and certified pH reference solutions. First, the pH meter calibration specifications declared by the manufacturer were verified, using a pH calibrator. The linearity of the potential response of the electrode for different pH was verified and the efficiency of the electrode was evaluated, finding a value of 98.39%. The calibration model was determined between the pH response of the instrument and the pH values established in certified reference solutions of pH 4.00, 7.00 and 10.00, finding a slope value equal to 1 and an intercept of 0, which indicates the good performance of the instrument. Finally, a repeatability study was carried out for 5 consecutive days using the Bartlett test to compare the precision of each series of results and ANOVA of one factor to compare the means of each day. Finally, the control charts for the pH of the certified reference solutions were prepared, in order to carry out quality control in routine measurements.
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