[303778] Artigo – CBM – Congresso Brasileiro de Metrologia

Resumo:  This article presents a study that evaluated the uncertainty in determining additive elements in lubricating oils. The aim of the study was to develop an uncertainty assessment process for calcium, phosphorus, and zinc, identifying the main sources of uncertainty and proposing improvements in the analysis process. The study utilized the technique of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to perform the measurements of the additive elements. Three analysts were selected to conduct the measurements in the same system, and the conditions of repeatability were evaluated for each analyst. Several sources of uncertainty were identified, including the analytical standard, calibration curve, volumetric dilution, glassware calibration and resolution, balance resolution and calibration, as well as repeatability. The results showed that analysts Y and Z obtained results within the specified limits, indicating good trueness and precision. On the other hand, analyst X yielded results close to the lower limits, highlighting the importance of analyst training and experience. One of the main conclusions of the study was the need for optimization in the sample preparation process, suggesting the substitution of volumetric dilution with mass dilution as a viable option to reduce sources of uncertainty and improve result reliability. In summary, the study emphasizes the importance of uncertainty assessment in determining additive elements in lubricating oils, emphasizing the need to understand and quantify sources of uncertainty to make reliable decisions and strive for more accurate results. Additionally, it highlights the significance of adequate analyst training and the implementation of rigorous sample preparation procedures to achieve reliable and high-quality results.