title: Determination of mercury in SRM crude oils and refined products by isotope dilution cold vapor ICP-MS using closed-system combustion.
abstract: Mercury was determined by isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS) in four different liquid petroleum SRMs. Samples of approximately 0.3 g were spiked with stable (201)Hg and wet ashed in a closed system (Carius tube) using 6 g of high-purity nitric acid. Three different types of commercial oils were measured: two Texas crude oils, SRM 2721 (41.7+/-5.7 pg g(-1)) and SRM 2722 (129+/-13 pg g(-1)), a low-sulfur diesel fuel, SRM 2724b (34+/-26 pg g(-1)), and a low-sulfur residual fuel oil, SRM 1619b (3.5+/-0.74 ng g(-1)) (mean value and 95% CI). The Hg values for the crude oils and the diesel fuel are the lowest values ever reported for these matrices. The method detection limit, which is ultimately limited by method blank uncertainty, is approximately 10 pg g(-1) for a 0.3 g sample. Accurate Hg measurements in petroleum products are needed to assess the contribution to the global Hg cycle and may be needed in the near future to comply with reporting regulations for toxic elements.
authors.affiliation: Analytical Chemistry Division, Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA. william.kelly@nist.gov
authors.forename: W Robert
authors.initials: WR
authors.lastname: Kelly
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Long
authors.forename: Jacqueline L
authors.initials: JL
authors.lastname: Mann
mesh_terms: D000397:Air Pollution / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D005742:Gasoline / Q000032:analysis; D006358:Hot Temperature; D008628:Mercury / Q000032:analysis*; D008629:Mercury Isotopes / Q000032:analysis; D010578:Petroleum / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D005742:Gasoline; D008629:Mercury Isotopes; D010578:Petroleum; D008628:Mercury