Dissolved organic matter (DOM) in oil refinery process water was fractionated by XAD-8 resin techniques into four subfractions: hydrophobic acid (HOA), hydrophobic base (HOB), hydrophobic neutral (HON), and hydrophilic substance (HIS) fractions. Negative and positive electrospray ion (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the composition of DOM and its subfractions. Compounds with multi-oxygen atoms were found to be predominant in DOM by either negative or positive ESI analysis, which are similar in composition to most other treated water samples. The DOM in the HOA fraction had a similar molecular composition to that of raw process water by negative ESI analysis. The DOM in the HOB fraction had a low molecular weight (MW) when analyzed by positive ESI, and basic nitrogen compounds, such as N 1 class species, were found to be predominant. The DOM in the HON fraction was predominantly O 2 class species. The DOM in the HIS fraction had a relatively wide MW distribution. All of the compounds of DOM in the HIS fraction exhibited low double bond equivalents (DBE) and low carbon numbers. The results showed that the use of the XAD-8 resin fractionation technique is valuable for characterizing trace quantities of DOM components in process water because their spectral peaks would otherwise be obscured by other abundant peaks. The origin and determination of chlorine-containing compounds, which are abundant in the negative ESI mass spectra of HOB, were discussed.
Anaerobic biodegradationAerobic biodegradation Oxidation by bio-aeration Activated carbon filtration Refinery wastewater 284.95 285.00 285.05 285.10 285.15 285.20ABSTRACT A set of wastewaters sampled in a stream-by-stream flow of the process in a refinery wastewater treatment plant were characterized to investigate the molecular composition and transformation of dissolved organic matter (DOM). The samples were separated into organic and aqueous phase DOMs by solvent extraction and solid phase extraction (SPE). Volatile and semi-volatile compounds in the organic phase were characterized by gas chromatography -mass spectrometry (GC-MS); DOMs in the organic and aqueous phase were characterized by negative ion electrospray (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The aqueous phase DOMs exhibited more complex molecular composition than other complex mixtures investigated by far, in which there were totally 76 compound class species identified in a single mass spectrum. Refinery wastewater DOMs have lower values of double bond equivalent (DBE) and O/C ratio than those of natural organic matters (NOMs) in fresh and marinewaters. The organic phase DOM occupied the major TOC value, but was liable to be degraded in the biological process. Some humic-like substances presented in the aqueous DOM were found resistant for the treatment processes by the ESI FT-ICR MS based semi-quantitative results.
Tea polyphenols (TP) is the main functional substances in tea. It has been reported that TP can modulate the composition of gut microbes in the human body, in addition, after the bio‐transformation by intestinal flora, the metabolites of TP also have positive effects on the health of the host. Lots of researches have shown that TP have possible therapeutic effect against high fat diet induced obesity, which is closely related to the gut flora of the host. Therefore, this review focused on the interactions of TP with intestinal microbiota and their implication for cellular signal conditioning mechanism that will enable us to better study the two‐way effects of TP and intestinal microbiota on host health improvement.
Practical applications
TP have been widely concerned for their health care properties. As the functional food components, TP have strong antioxidant and physiological activities for human body. A better understanding on the interactions of TP with intestinal microbiota and their implication for cellular signal conditioning mechanism will lead us to better evaluate the contribution of the microbial metabolites of TP, as well as the regulation of intestinal bacterial diversity and abundance for host health.
Free fatty acids (FFAs) and triacylglycerols (TAGs) are the main components of edible vegetable oils. In this work, electrospray ionisation (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was employed to characterise the molecular composition of FFAs and TAGs in various vegetable oils, including soybean, rapeseed, corn, sunflower, peanut, linseed and olive oils. Semiquantitative analysis of FFAs and structural analysis of TAGs by MS/MS were further conducted to reveal the differences in the molecular compositions of the various vegetable oils. It was found that each vegetable oil has characteristic fingerprints of FFAs and TAGs. MS/MS measurements showed that the high-abundance TAGs in each vegetable oil were mainly composed of their abundant FFAs and glycerol. FFA and TAG fingerprints of genetically modified (GM) and nongenetically modified (non-GM) vegetable oils were similar, exhibiting only subtle differences, as confirmed by principal component analysis (PCA).
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