Evaluation of stability of ethanol in water certified reference material: measurement uncertainty under transport and storage conditions

Abstract

This study simulated the transport and storage conditions of ethanol in water certified reference material (CRM) produced by the Chemical Metrology Division of Inmetro – DQUIM with the purpose to estimate the measurement uncertainty related to stability. The short-term stability study was performed on five different concentrations in terms of g ethanol/100g solution (%) of the ethanol in water CRM: 0.0509%, 0.0890%, 0.1145%, 0.3820% and 0.4960%, at the temperatures of 4 ºC and 60 ºC. On the other hand, the longterm stability study was developed on four different concentrations: 0.0509%, 0.0890%, 0.1145% and 0.4960%. In this paper will be shown data from the long- term stability study concerning 20 weeks. The method used complies with ISO GUIDE 35, BCRGuideline for Feasibility Studies and ISO GUIDE 34. According to the statistical parameters used in both studies the stability of the ethanol in water CRM was confirmed for all concentrations studied.