| Abstrakt: |
Sodium chloride (NaCl or salt) is one of the inorganic minerals widely used by various industries, causing the demand for salt to be very high, including in Indonesia. Through the National Standardization Agency (BSN), the Indonesian government released national standards (SNI) to protect the salt industry and consumers. Therefore, an appropriate analytical method is required to determine NaCl in a salt sample, supporting quality and standards implementation. The standard method used for testing NaCl is the argentometric titration performed by the Mohr method or potentiometric method. This work studies the verification of these two methods in NaCl purity determination to obtain the appropriate method for certified reference material (CRM) certification. The verification consisted of accuracy, precision, the limit of determination, and measurement uncertainty evaluation. In this study, the Mohr method showed accurate results at a sample size of at least 82.01 mg, and the potentiometric method showed accurate results at a sample size of at least 81.44 mg, performed by measuring the NaCl CRM and statistical evaluation. A 0.3% precision (calculated as relative standard deviation) was achieved using a sample size of 97 mg and 85 mg for the Mohr and potentiometric methods, respectively. At the same condition applied in NaCl determination, expanded measurement uncertainty was estimated at 0.59% and 0.87% for the potentiometric and Mohr methods, respectively. Comparing the two methods detected that potentiometric titration offers a more accurate method to quantify NaCl purity. The method will be reasonably considered for future work in CRM production and certification. [ABSTRACT FROM AUTHOR] |
