• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3151-3155
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• 2010

This study was performed to develop analytical methods to better understand the properties and reactivity of petroleum, which is a highly complex organic mixture, using high-resolution mass spectrometry and statistical analysis. Ten crude oil samples were analyzed using negative-mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Clustering methods, including principle component analysis (PCA), hierarchical clustering analysis (HCA), and k-means clustering, were used to comparatively interpret the spectra. All the methods were consistent and showed that oxygen and sulfur-containing heteroatom species played important roles in clustering samples or peaks. The oxygen-containing samples had higher acidity than the other samples, and the clustering results were linked to properties of the crude oils. This study demonstrated that clustering methods provide a simple and effective way to interpret complex petroleomic data.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.165-172
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• 2014

The distribution of basic nitrogen-containing compounds in three vacuum gas oils (VGOs) with different boiling ranges and their dewaxed oils from the lube base oil refining unit of a refinery were characterized by positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). It turned out that the composition of basic nitrogen compounds in the samples varied significantly in DBE and carbon number, and the dominant basic N-containing compounds in these oil samples were N1 class species. $N_1O_1$, $N_1O_2$, and $N_2$ class species with much lower relative abundance were also identified. The composition of basic nitrogen compounds in VGOs and dewaxed VGOs were correlated with increased boiling point and varied in DBE and carbon numbers. The comparison of the analytical results between VGOs and dewaxed VGOs indicated that more basic N-containing compounds in VGO with low carbon number and small molecular weight tend to be removed by solvent refining in lube base oil processing.

• Proceedings of the Microbiological Society of Korea Conference
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• 2008.05a
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• pp.163-163
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• 2008

Methylophaga aminisulfidivorans $MP^T$, a restricted facultative marine methylotrophic bacterium, was able to utilize methanol as a sole carbon and energy source, and possessed a methanol dehydrogenase (MDH) that is a key enzyme in the process of methanol oxidation. During purification of MDH, three types of MDH (MDH I, II, and III) were obtained in the cell free extracts from $MP^T$ cells grown on methanol. When analyzed by SDS-PAGE and ESI-FT ICR MS, MDH I was confirmed to consist of two subunits and with molecular masses of ~66 and ~10 kDa, respectively, in a form of ${\alpha}_2{\beta}_2$. While MDH II and MDH III contained an additional ~30 kDa protein, designated ${\gamma}$, in a form of ${\alpha}_2{\beta}_2{\gamma}$ and ${\alpha}_2{\beta}_2{\gamma}_2$, respectively. MDH III showed 1.5.2.0 times higher activity than MDH II, while MDH I remained the lowest activity. Based on these observations and experimental data, it seems that the original MDH conformation is ${\alpha}_2{\beta}_2{\gamma}2$ within $MP^T$ growing on methanol, and subunit ${\gamma}$ keeps MDH in an active form, and/or makes MDH easily bind to the substrate, methanol.