What: A unit of SRM 2778 consists of five amber glass ampoules, each containing approximately 10 mL of crude oil. The certified mass fraction of total mercury in SRM 2778 is 38.98 mg/kg ± 1.10 mg/kg, with the expanded uncertainty expressed at an approximate level of confidence of 95 %.
Why: SRM 2778 is intended to serve as a validation standard for methods of mercury analysis used in the oil refining industry to support the accurate measurement of mercury content in source crude materials for process, environmental, and safety compliance assessments. Mercury content in source (unprocessed) crude oil is an important measurand that helps flag potential corrosion risks to equipment employed in oil refining processes. SRM 2778 was developed in response to customers requesting a fit-for-purpose material with elevated mercury content. The certified mercury mass fraction in SRM 2778 is two to three orders of magnitude higher compared to previously issued NIST crude oil SRMs certified for mercury, and is representative of the upper scale range of expected mercury mass fraction in global crudes.
Who: The customers that will use this SRM range from private sector laboratories and testing companies operating in the oil refining industry, US Government laboratories (EPA, DOE), academic institutions, commercial instrument manufacturers, and other national and international stakeholders that contribute measurements and data used for the generation and prediction of global mercury budgets and sources of mercury emissions to the ecosphere.
How: The issuance of SRM 2778 will assist oil industry testing laboratories measuring total mercury mass fraction in crude oil samples by combustion atomic absorption spectroscopy and other instrumental methods. SRM 2778 will provide a matrix-similar control to help verify the calibration of instruments and assess accuracy for mercury mass fraction measurements of unknown crude oil samples. Providing a certified mercury mass fraction standard for crude oil will also assist with benchmarking the quality and accuracy of mercury data being utilized for budgeting airborne mercury pollution associated with world oil refining production, which accounts for approximately 14.5 metric tons of emitted mercury annually, roughly 1 % of the total global mercury emissions budget. (Source: United Nations Environment Program Global).