Understanding the vanadium−asphaltene nanoaggregate link with silver triflate complexation and GPC ICP-MS analysis

Abstract : The effect of silver triflate (AgOTf) on the interaction between vanadium and asphaltene nanoaggregates was investigated by gel permeation chromatography inductively coupled plasma high-resolution mass spectrometry (GPC ICP-HR-MS). The results showed that disaggregation of some vanadium compounds linked to asphaltene nanoaggregates occurred when silver triflate was added. Ag+ can partially move some porphyrins from the high-molecular-weight (HMW) region to the low-molecular-weight (LMW) region. It was inferred that the interaction between Ag+ and the porphyrins surroundings led to a decrease in the size of the nanoaggregates (HMW region) and an increase in the “free” V porphyrin compounds (MMW and LMW regions). Asphaltenes from a similar origin, presenting the same vanadium GPC ICP-MS profile, gave different GPC ICP-MS profiles after AgOTf addition, which could be linked to the difference in geochemistry of the samples.