The Impact of the Recovery in the Uncertainty Evaluation of the Oil and Grease by Extraction and Gravimetry in Produced Waters Derived From the Petroleum Extraction Process

摘要

It is a current practice for chemical analysts to use recovery in their analysis, but seldom, this source of uncertainty is evaluated. Thus, this topic takes the authors out of the comfort zone. Although recovery, in some situations, can be negligible, not always its source of uncertainty can be not. The authors discuss the uncertainty contribution of the recovery using an example the oil and grease by extraction and gravimetry in produced waters derived from petroleum extraction process. The results show that the uncertainty of the recovery can be the greatest source. It can be mainly observed when certified reference materials to evaluate the recovery have high uncertainties. Even when the recovery does not need to be computed, based on statistical tests, the relevance of the recovery, as an uncertainty source, cannot be negligible, deciding if oil and grease content meets the legal regulation.