Uncertainty Estimation for Determination of Potassium Iodate Purity by Potentiometric Titrimetry

Öz

The purpose of this study was to express the uncertainty estimation for the purity determination of potassium iodate by potentiometric titrimetry method. Potassium iodate determination by using a potentiometric titrator was realized in two steps. In the first step, a factor analysis is performed using sodium thiosulfate. In the second step, the amount of potassium iodate was determined by using the factor value obtained in the first step of the measurement. Sigma Aldrich 60386 CRM (certified by BAM-with purity of 99.94%) was used for factor analysis. The documents of “Evaluation of measurement data - Guide to the expression of uncertainty in measurement” and “EA-4/02 M: 2013 Evaluation of the Uncertainty of Measurement in Calibration” were the source for the evaluation of the measurement uncertainty. The documents of “EURACHEM/CITAC Guide CG 4, JCGM 100: 2008” and “Eurolab Technical Report No.1/2007” based on the bottom-up approach were also paid regard during the uncertainty estimation study. The main factors that are forming the total uncertainty budget were repeatability of measurement results, titrant consumption, factor of sodium thiosulfate, the molar mass of potassium iodate and sample quantity. It was observed that the highest contribution to the uncertainty budget was the repeatability of measurement results. The measurement result for the purity determination of potassium iodate was found as 99.76% and the expanded uncertainty of the measurements was estimated as 0.12% which was acceptable level for the study.

Anahtar Kelimeler

• Potentiometry
• titrimetry
• potassium iodate
• measurement uncertainty
• bottom-up approach

Kaynakça

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