Speciation of Metals in Asphaltenes by High-Performance Thin-Layer Chromatography and Laser Ablation Inductively Coupled Plasma-Mass Spectrometry

Abstract

Asphaltenes are considered the most problematic components of heavy oils because they can self-aggregate which leads to precipitation and causes various problems during oil recovery, transportation and refining. The contribution of the porphyrins present in asphaltenes to the aggregation cannot be studied by direct elementary analysis techniques since in this form, the porphyrins are complexed with metals. Thus, gel permeation chromatography inductively coupled plasma-mass spectrometry (GPC-ICP MS) has been used in previous studies. The results

Speciation of Metals in Asphaltenes by High-Performance Thin-Layer Chromatography and Solid–Liquid Extraction Hyphenated with Elemental and Molecular Identification

“…Thus, our results suggest that separation by HPTLC allows for the isolation of porphyrins that are not bound in asphaltene aggregates, as already proposed in our previous paper. 32 For the whole PetroPhase 2017 sample, the results obtained by UV (Figure 2) and laser ablation (Figure 3) are quite similar to our previous results. 32 Indeed, nearly 80% of the vanadium remained at the deposition point (Table 3, LA-ICP-MS analysis).…”

“…32 For the whole PetroPhase 2017 sample, the results obtained by UV (Figure 2) and laser ablation (Figure 3) are quite similar to our previous results. 32 Indeed, nearly 80% of the vanadium remained at the deposition point (Table 3, LA-ICP-MS analysis). In that work, the Asphaltene 2017 sample was also analyzed by MALDI FT-ICR MS, but no porphyrins were detected at the deposition point.…”

“…For the whole PetroPhase 2017 sample, the results obtained by UV (Figure ) and laser ablation (Figure ) are quite similar to our previous results . Indeed, nearly 80% of the vanadium remained at the deposition point (Table , LA-ICP-MS analysis).…”

“…As shown by Evdokimov et al [15], porphyrins can be "invisible" in UV-Vis spectroscopy due to aggregation. Thus, our results suggest that separation by HPTLC allows for the isolation of porphyrins that are not bound in asphaltene aggregates, as already proposed in our previous paper [32].…”

“…Our previous works [32] using GPC-HPTLC with LA-ICP-MS suggest that porphyrins that migrate until the solvent front using DCM/MeOH were more accessible as free porphyrins than those that remained at the deposition point. Here, extrography followed by HPTLC separation was used on asphaltene samples.…”