二次元クロマトグラフィー

Lignin as a natural antioxidant is currently gaining interest as a renewable substitute for fossil-based antioxidants. Here, two-dimensional liquid chromatography (size-exclusion and reversed-phase chromatography) coupled with a post-column radical scavenging assay (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS)) is used to profile the antioxidant activity of softwood Kraft lignin. This method can assign antioxidant activity to different molecular weight fractions (monomeric, oligomeric, polymeric) within the complex lignin matrix. Four guaiacyl-type monomeric compounds (guaiacol, acetovanillone, vanillic acid, and vanillin) were identified in the lignin sample, consistent with softwood lignin composition; however, antioxidant activity varies widely among them. Guaiacol shows the highest specific radical scavenging activity, whereas vanillin's activity is lower than the detection limit. Antioxidant activity was also detected for oligomeric and polymeric domains. For polymeric lignin higher specific antioxidant activity was detected with decreasing molecular weight. This approach provides a more detailed understanding of lignin's structure-property relationship regarding its antioxidant activity than conventional bulk-type assays or solvent fractionation experiments, thereby guiding the selection of lignin fractions for antioxidant applications.

Polybrominated diphenyl ethers (PBDEs) and organophosphate flame retardants (OPFRs) are two groups of chemical compounds commonly found in the aquatic environment, mainly because of their widespread use in consumer and industrial products. These substances can accumulate in fish, especially in fatty tissues, raising concerns about their possible transfer to humans through diet. In this study, an analytical methodology was developed and validated to detect and quantify PBDEs and OPFRs in fish samples using a modified QuEChERS extraction followed by two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOF MS) analysis. The method showed good performance in terms of recovery, precision, and detection limits. The two-dimensional chromatography allowed for better separation of isomer compounds, which are often difficult to be analyzed using conventional methods. This approach provides a reliable and sensitive tool for monitoring flame retardants in fish and can contribute to assessing both environmental contamination and potential risks for consumers.

Selenium bioaccessibility assessment in selenized yeast after “in vitro” gastrointestinal digestion using two-dimensional chromatography and mass spectrometry

Development of an algorithm for peak detection in comprehensive two-dimensional chromatography

With the combination of different mechanisms, two-dimensional liquid chromatography has brought revolutionary changes compared to the traditional one-dimensional separation, which dramatically improve the peak capacity in separation and meet the ever-increasing demand for the analysis of complex samples in different research fields, such as chemistry, medicine, etc. However, the incompatibilities between two columns due to the transport of the large sample volume and the solvent effect always limit the wide use of two-dimensional liquid chromatography. In order to resolve this problem an at-column dilution (ACD) modulator was established to overcome the solvent incompatibility in the orthogonal combination within the comprehensive two-dimensional liquid chromatography. This interface is modified from normal two-dimensional interfaces by an additional transfer pump, which realize the at-column dilution without a flow split during the transportation. Moreover, with the control of the transfer flow and the second-dimensional gradient flow, it is able to precisely regulate the at-column dilution factor and conveniently optimize the separation conditions in both dimensions. In this work, a systematic research has been done between the setups with/without the at-column interface in the combination of reversed-phase liquid chromatography and hydrophilic interaction chromatography (RPLC × HILIC) and HILIC × RPLC, which proved that the at-column interface is able to resolve the solvent conflict problem very well. Furthermore, red ginseng was chosen as a real sample to investigate the applicability of the at-column dilution modulator for comprehensive two-dimensional chromatography with high orthogonality.

39] Chromatographic characterization of oligonucleotides on DEAE paper

Coupled size-exclusion chromatography-anion-exchange chromatography in the analysis of poly- and oligosaccharides

Comprehensive two-dimensional reverse phase countercurrent chromatography (CCC)×high performance liquid chromatography (HPLC) was investigated for chemical profiling and identification of bioactive components with anti-inflammatory activities for a traditional Chinese medicine formula, Hongteng Baijiang decoction (HBD), for the first time.Anti-inflammatory activity of different extractions from HBD were evaluated.Two-dimensional contour plots for CCC×HPLC were obtained after comprehensive separation was completed. The total peak capacity of the two-dimensional system was evaluated, yielding approximately 782 peaks through comprehensive two-dimensional separation, which demonstrated a high degree of orthogonality and large separation space occupancy of 90.16%. Totally 207 chemical components were identified in ethyl acetate extract from HBD using liquid chromatography-quadrupole time-of-flight mass spectrometry based on the two-dimensional separation, with additional 70 compounds identified compared to that in one-dimensional HPLC separation. It was found that terpenoids were major bioactive components contributing to anti-inflammatory bioactivity in HBD. These findings highlight the potential of comprehensive two-dimensional chromatography (CCC×HPLC) as a powerful and promising method for separating and chemical profiling for complex traditional Chinese herbal formula.

Baseline correction method for dynamic pressure gradient modulated comprehensive two-dimensional gas chromatography with flame ionization detection

Separation and analysis of phenolic acids from Salvia miltiorrhiza and its related preparations by off-line two-dimensional hydrophilic interaction chromatography × reversed-phase liquid chromatography coupled with ion trap time-of-flight mass spectrometry

The aim of this study was to investigate the impact of chemo-radiotherapy on serum protein expression of the esophageal cancer patients and discover potential biomarkers by detecting serum proteins mass spectrometry of the healthy Kazakh people in Xinjiang as well as the patients before and after their chemo-radiotherapy. In order to separate and compare the three serum samples (the healthy group's, the patients' before and after chemo-radiotherapy) with two-dimensional protein liquid chromatography system (Proteome LabTM PF-2D), then detect the differential protein spots with linear trap quadruple mass spectrometer (LTQ MS/MS). (1) The Kazakh esophageal cancer patients got 21 expressed protein spots peaks with significant difference after chemo-radiotherapy compared with before; before the treatment there were 10 different expressed protein spots compared with the healthy group, and after it there were four peaks in the expression of protein spots compared with the healthy group. (2) After LTQ mass spectrometric detection, 22 proteins were up-regulated in serum samples of the healthy group, 22 were up-regulated of the patients before medical treatment and 5 were up-regulated after chemo-radiotherapy. (3) 8 proteins including APOA1 can be served as serum markers in Kazakh esophageal cancer diagnosis, and proteins like CLU can be served as serum markers in judging the resistance and sensitivity towards chemo-radiotherapy. (4) The abnormal expressions of APOC2, APOC3, Antithrombin-III in esophageal cancer were discovered for the first time. Specific protein spots related to Xinjiang Kazakh esophageal cancer diagnosis and chemo-radiotherapy can be identified in the serum, which will probably become a maker in Kazakh esophageal cancer diagnosis and therapeutic evaluation.

Supercritical fluid extraction was coupled to comprehensive two-dimensional supercritical fluid chromatography with conventional packed columns. With this system, three modes of operations were feasible, such as SFE-SFC, SFCxSFC, and SFE-SFCxSFC. The operations for valve switching and data acquisition were automated using in-house software. In order to evaluate the present system, SFE-SFC for polymer additives in polypropylene, SFCxSFC for a mixture of benzene derivatives with different polarities, and SFE-SFCxSFC for styrene oligomers in polystyrene were performed. With SFE-SFCxSFC, diastereomers were resolved for linear tetramers and pentamers as well as trimers with the tetraline moiety.

Citrus aurantium (bitter orange), is widely used in culinary preparations, food supplements, cosmetics and traditional medicine. Its bioactivity is mainly associated to two major glycosylated flavanones, naringin and neohesperidin, each comprising two diastereoisomers having different bioactivities. To possibly relate bioactivity to stereoisomeric composition, an analytical method was necessary. A two-dimensional supercritical fluid chromatography (SFC) method was used to measure diastereomeric excesses of the flavonoids in bitter orange organs, including flowers, leaves and fruits at different stages of maturity. The extracts were prepared with supercritical fluid extraction (SFE) with CO2, ethanol and water. SFE conditions were defined following a 3-factor Box-Behnken design of experiments. While neohesperidin was highly stable, with circa 100% stereomeric excess in all samples, naringin was prone to racemization, especially in mature fruits. This study also examined the importance of using a sufficient mass of sample to obtain accurate and meaningful measurements, particularly when stereoisomers are concerned.

Quantitative determination of amino acids on filter paper staining in two stages

Enoxaparin, one of the most important low-molecular-weight heparins (LMWHs), is widely used as a clinical anticoagulant. Different production processes and animal sources of its precursor (unfractionated heparin) can result in the structural diversity of enoxaparin. In this study, 38 lots of enoxaparin prepared at different times, from different providers and animal sources, were systematically analyzed. SEC and SAX were used to analyze the oligosaccharide dispersity and structural compositions (disaccharide domains) of enoxaparins by size and charge, respectively. The results provide clues as to whether the structural variations in enoxaparin, observed in oligosaccharide mapping and/or disaccharide analysis, are attributable to differences in the animal sources of its heparin precursor or enoxaparin production processes based on times or brands. The representative enoxaparins were fingerprinted with online multiple heart-cut two-dimensional liquid chromatography-mass spectrometry (MHC-2DLC-MS). The profiles in MHC-2DLC-MS showed the detailed structural information of enoxaparins. In addition, the binding capacities to antithrombin III (AT) of these 38 lots of enoxaparins were detected using surface plasmon resonance (SPR) with the competitive inhibition mode. The results showed that the glycan size distribution of an enoxaparin is more related to its production process. The disaccharide composition, sequence and the variety of glycans of an enoxaparin are more related to its AT binding-based anticoagulant activity.