Journal Published Online: 01 October 2005
Volume 2, Issue 9

Direct Trace and Ultra-Trace Metals Determination in Crude Oil and Fractions by Inductively Coupled Plasma Mass Spectrometry

CODEN: JAIOAD

Abstract

A method was developed to analyze direct trace and ultra-trace metal elements in crude oil and its fractions (maltenes-asphaltenes) by ICP-MS after sample dilution in xylene. Efficient introduction of organic compounds requires addition of O2 for complete combustion of the sample, carbon deposit on cones (interface) and extraction lenses was minimized by optimization of argon to oxygen ratio in the plasma. A PFA-100 (100 μl.mn−1) MicroFlow Nebulizer and a Scott “double pass” chilled spray chamber were associated for an optimal introduction of petroleum products. The Q-ICP/MS was equipped with platinum cones to limit drifts caused by cone corrosion during an organic analysis. A standard addition method was realized for the calibration procedure in order to control the matrix effects. Method validation was completed by analyzing three certified reference materials from the National Institute for Standards and Technology (NIST). NIST 1085b, NIST 1084a, and NIST 1634c accuracies were approximately 10 %. Detection limit of ultra trace elements in xylene were at pg.g−1 level. A clean PFA filter system was developed to separate the oil fractions (maltenes and asphaltenes) by precipitation of asphaltenes (heavy fraction) in n-heptane. For optimal detection conditions, the samples were diluted in xylene according to their pre-estimated element concentration range. Total mass balance shows a recovery close to 100 % for Ni, V, Cu, Mo, Ag, Sn, Ba, and Pb. These results show that elements analyzed are highly concentrated in the asphaltenic fraction.

Author Information

Dreyfus, S
LCABIE/CNRS UMR 5034, Pau Cedex 9, France Institut Français du Pétrole, Rueil Malmaison Cedex, France
Pécheyran, C
LCABIE/CNRS UMR 5034, Pau Cedex 9, France
Magnier, C
Institut Français du Pétrole, Rueil Malmaison Cedex, France
Prinzhofer, A
Institut Français du Pétrole, Rueil Malmaison Cedex, France
Lienemann, CP
Institut Français du Pétrole, Rueil Malmaison Cedex, France
Donard, OFX
LCABIE/CNRS UMR 5034, Pau Cedex 9, France
Pages: 8
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Stock #: JAI12969
ISSN: 1546-962X
DOI: 10.1520/JAI12969