Combining Fourier Transform-Ion Cyclotron Resonance/Mass Spectrometry Analysis and Kendrick Plots for Silicon Speciation and Molecular Characterization in Petroleum Products at Trace Levels

A new method combining FT-ICR/MS analysis and Kendrick plots for the characterization of silicon species at trace levels in light petroleum products is presented. The method provides efficient instrumental detection limits ranging from 80 ng/kg to 5 μg/kg and reliable mass accuracy lower than 0.50 ppm for model silicon molecules in spiked gasoline. More than 3000 peaks could be detected in the <i>m</i>/<i>z</i> 50–500 range depending on the nature of the gasoline sample analyzed. An in-house software program was used to calculate Kendrick plots. Then, an algorithm searched, selected, and represented silicon species classes (O₂Si, O₃Si, and O₄Si classes) in Kendrick plots by incorporating model molecules' information (i.e., exact mass and intensity). This procedure allowed the complete characterization of more than 50 new silicon species with different degrees of unsaturation in petroleum products

New Insights into Resid Desulfurization Processes: Molecular Size Dependence of Catalytic Performances Quantified by Size Exclusion Chromatography-ICP/MS

Fixed-bed resid desulfurization (RDS) is an important industrial catalytic process to produce low sulfur fuel oil and to pretreat feed for resid fluid catalytic cracking (RFCC) unit. The catalytic system is based on a complex stacking of task-specific catalysts. To improve the RDS performances, it is crucial to better understand and monitor the nature and amount of contaminants (especially sulfur and metals) along the process. In the present paper, an hyphenated technique based on Size Exclusion Chromatography separation (SEC) and Inductively-Coupled Plasma/Mass Spectrometry (ICP/MS) detection is applied to develop an innovative quantitative method: it allows to quantify the refractory compounds related to their molecular size. The analysis of the effluents arising from the different catalyst beds demonstrates the selectivity of each catalyst toward the molecular size of sulfur and vanadium containing molecules