The aim of this study is the development of a separation technique for geological samples, namely bismuthinites, with the goal to isolate Tl from excess amounts of Bi. This will enable an isotopic ...measurement of the Tl content on the ultra-trace level to identify a possible signature of Bi alpha-decay. The separation of Tl from other elements like e.g. Pb has been the subject of numerous studies. However, the separation of ultra-traces of Tl from bulk Bi had not yet been investigated sufficiently. This paper describes a separation technique for the system Bi/Tl for application to ultra-trace analysis. The separation technique uses a column chromatographic system, utilizing the specific redox behavior of Tl. The results show, that Tl can be successfully separated in appearance of vast excess amounts of Bi, showing recovery rates up to 96%. The developed procedure was successfully applied for the ultra-trace analysis on a number of bimuthinites using ICP-MS. On base of the results it is discussed, which prerequisites bimuthinite samples must fulfill to be suitable for the quantification of Bi alpha decay on base of the Tl isotopic ratio.
► Comprehensive LC×LC for analysis of di- to deca-oligonucleotides is described. ► HILIC is used in the first dimension and IP-RPLC in the second dimension. ► The coupling of HILIC×IP-RPLC to ESI-MS ...is presented.
A comprehensive two-dimensional HPLC approach with a high degree of orthogonality was developed for analysis of di- to deca-oligonucleotides (ONs). Hydrophilic interaction liquid chromatography (HILIC) was used in the first dimension, and ion-pair reversed-phase liquid chromatography (IP-RPLC) was employed in the second dimension. The two dimensions were connected via a ten-port valve interface equipped with octadecyl silica (ODS) traps to immobilize and focus the ONs eluting from the first dimension prior to IP-RPLC separation. An aqueous make-up flow was used for effective trapping. The comprehensive two-dimensional HPLC system was optimized with a mixture consisting of 27 oligonucleotide standards. An overall chromatographic peak capacity of 500 was obtained. The use of the volatile buffer triethylamine acetate in the second dimension allowed straightforward coupling to electrospray ionization mass spectrometry (ESI-MS) and detection of each ON in the negative ionization mode.
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Introduction
Cell membrane chromatography (CMC), as a highly selective type of affinity chromatography, has been demonstrated as an effective method to screen bioactive components acting on specific ...receptor from a complicated biological system.
Objective
To review the recent research progress and the technical applications of these analytical methods using CMC combined with gas chromatography‐mass spectrometry, (GC/MS) and liquid chromatography‐mass spectrometry (LC/MS).
Methodology
In this review, we briefly introduce the CMC offline GC/MS, CMC online GC/MS, CMC offline LC/MS, and CMC online LC/MS system. And the practical application of these technologies is also enumerated. Then the future of these technologies and research methods were discussed.
Results
Many bioactive components interacting with specific receptors have been screened and identified in traditional Chinese medicines.
Conclusion
CMC technique has been combined with GC/MS and HPLC/MS and these combined systems have been successfully used to screen bioactive components acting on specific receptors from a complicated biological system.
We briefly introduce the CMC offline GC/MS, CMC online GC/MS, CMC offline LC/MS, and CMC online LC/MS system. And the practical application of these technologies is also enumerated. The CMC technique has been combined with GC/MS and HPLC/MS and these combined systems have been successfully used to screen bioactive components acting on specific receptors from a complicated biological system.
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► Brief overview on the main step of the development of the LC–GC technique. ► Main interfaces, principal and applications. ► Normal-phase and reverse-phase liquid-chromatography coupling to gas ...chromatography. ► Applications of LC–GC over the last decade.
Liquid chromatography (LC) hyphenated with gas chromatography (GC) was first presented in 1979. Since then an intensive study has been carried out to explore different types of interfaces both for coupling normal-phase (NP) and reverse-phase (RP) LC with GC. The present review focuses on the technical progress and applications presented in the last decade, and it describes the most used interfaces. In fact, more flexible interfaces have been studied to improve the use of LC–GC, in particular the use of a programmed temperature vaporizer (PTV) injector. An intensive effort has also been devoted to optimizing the coupling of reverse-phase LC for analysis of water-based samples. A brief overview of comprehensive approaches (LC×GC) is discussed along with perspective for further improvement of the technique.
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The behavior of group-4 homologs Zr and Hf on extraction-chromatographic sorbents LN resin and TRU resin in mixtures of HF and HNO.sub.3 is considered. Distribution coefficients of the elements in ...the mixtures of 5·10.sup.-4 M-1 M HF and 0.01 M-5 M HNO.sub.3 are determined. Strong retention of both elements was found on LN resin in the range of concentrations c(HF) less than or equal to 0.01 M for all concentrations of HNO.sub.3. Retention tends to gradually disappear while increasing c(HF) to 0.5 M. On TRU resin retention is observed only in solutions with c(HNO.sub.3) greater than or equal to 2 M and c(HF) less than or equal to 0.01 M. The possibility of separating Zr(IV) and Hf(IV) on LN resin is illustrated in two different acid mixtures, whereas their separation on TRU resin under the conditions studied in this work is difficult. The results obtained can be used to isolate analytes from multicomponent mixtures during analytical tasks, as well as to separate them from each other.
While the amino acids, enzymes and hormones are chiral, chirality plays significant role in the life of plants, animals, as well as the human being. Chirality of molecules is important in various ...industries, such as pharmaceutical, agricultural, food, electronics, etc. Chiral drugs may have different bioavailability, distribution, biotransformation and excretion, as well as quantitatively and/or qualitatively different pharmacological or toxic properties. Enantiomerically pure chiral drugs have been increasingly developed for the pharmaceutical market due to their superiority from the viewpoints of potency and safety. This is supported by the development of new methods for enantioselective production of the chiral compounds, as well as by the capability of the enantioselective analytical methods to allow a detection and quantification of minor enantiomeric impurity in the presence of another enantiomer in a large excess. The aim of the present review is to provide a short summary of the basic principles of chiral separations on an analytical and preparative scale. In addition, some selected applications for analytical techniques, such as gas chromatography, supercritical fluid chromatography, high performance liquid chromatography, capillary electrophoresis and capillary electrochromatography for the separation of enantiomers of chiral pharmaceuticals published in the last two years are also discussed.
Cordycepin (3′-deoxyadenosine) is a potent bioactive metabolite of the medicinal fungus Cordyceps militaris, which has been increasingly exploited to treat various chronic diseases in humans. ...However, the current synthesis and purification procedures of cordycepin are principally laborious and complicated. This study provides a simple protocol approach to isolate and purify cordycepin from C. militaris by normal phase column chromatography at room temperature. Besides, this is the first to investigate the potential of cordycepin and cordycepin-included extracts from C. militaris for making Kombucha functional products. By a repeated column chromatography, an amount of 1.16 g of cordycepin is isolated from 2.8 kg of fruiting bodies of C. militaris, which obtained an efficiency of 83.26% compared to that estimated by high-performance liquid chromatography (HPLC). The purity of cordycepin is confirmed by thin-layer chromatography (TLC), HPLC, and proton nuclear magnetic resonance (sup.1H NMR). In addition, kombucha-fermented extracts from cordycepin and cordycepin-included fractions show potential biological activities in terms of antioxidant, anti-diabetes via α-glucosidase inhibitory assay, and cytotoxicity via MTT assay on Meg-01 and HL-60 cell lines. Further studies on optimization of extraction protocol and verification of health benefits of kombucha products from cordycepin should be conducted prior to the official mass production.
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•Analysis of ADC species as well as product and process related impurities is reviewed.•Modern liquid chromatographic methods and method development approaches are ...discussed.•Possibilities and limitations of multidimensional methods in ADC analysis are overviewed.•Future perspectives for liquid chromatographic ADC analysis are discussed.
Antibody Drug Conjugates (ADCs) are innovative biopharmaceuticals gaining increasing attention over the last two decades. The concept of ADCs lead to new therapy approaches in numerous oncological indications as well in infectious diseases. Currently, around 60 CECs are in clinical trials indicating the expanding importance of this class of protein therapeutics.
ADCs show unprecedented intrinsic heterogeneity and address new quality attributes which have to be assessed. Liquid chromatography is one of the most frequently used analytical method for the characterization of ADCs. This review summarizes recent results in the chromatographic characterization of ADCs and supposed to provide a general overview on the possibilities and limitations of current approaches for the evaluation of drug load distribution, determination of average drug to antibody ratio (DARav), and for the analysis of process/storage related impurities. Hydrophobic interaction chromatography (HIC), reversed phase liquid chromatography (RPLC), size exclusion chromatography (SEC) and multidimensional separations are discussed focusing on the analysis of marketed ADCs. Fundamentals and aspects of method development are illustrated with applications for each technique. Future perspectives in hydrophilic interaction chromatography (HILIC), HIC, SEC and ion exchange chromatography (IEX) are also discussed.
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Complex microbial metabolism is responsible for the unique flavor of Shaoxing mechanized huangjiu. However, the relationship between the microorganisms present during fermentation and the formation ...of specific flavor components is difficult to understand. In this study, gas chromatography–mass spectrometry and high-performance liquid chromatography were used to identify flavor components, and a metagenomic sequencing approach was used to characterize the taxonomic and functional attributes of the Shaoxing mechanized huangjiu fermentation microbiota. The metagenomic sequencing data were used to predict the relationship between microorganisms and flavor formation. The chromatographic analysis identified amino acids, alcohols, acids, phenols and esters as major flavor components, and six microbial genera (Saccharomyces, Aspergillus, Saccharopolyspora, Staphylococcus, Lactobacillus, and Lactococcus) were most closely related to the production of these flavor components. This study helps clarify the different metabolic roles of microorganisms in flavor formation during Shaoxing huangjiu fermentation.
•Flavor metabolic network in huangjiu microbiota was constructed.•Enzymes and genera in the formation of main flavors were annotated.•Six genera were closely related to huangjiu flavor formation.
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Introduction
The minor phenolic constituents of Cyclopia pubescens Eckl. & Zeyh. are unknown and one dimensional (1D) liquid chromatography (LC) is unable to provide sufficient separation.
...Methodology
A two‐dimensional (2D) LC method incorporating normal‐phasehigh performance countercurrent chromatography (NP‐HPCCC) in the first dimension (1D) and reversed‐phase ultra‐high‐performance liquid chromatography (RP‐UHPLC) as the second dimension (2D) was developed. The analytical HPCCC method was subsequently scaled up to semi‐preparative mode and fractions pooled based on phenolic sub‐groups. The phenolic compounds in selected fractions were subsequently isolated using RP‐HPLC on a C18 column. Isolated compounds were identified by nuclear magnetic resonance (NMR) spectroscopy. The absolute configurations of compounds were determined by optical rotation and electronic circular dichroism spectra. Sugars were identified by gas chromatography‐mass spectrometry (GC–MS) analysis.
Results
The comprehensive off‐line 2D CCC × LC method gave a good spread of the phenolic compounds. Orthogonality calculated using both the convex hull and conditional entropy methods were 81%. High‐resolution mass spectrometric fragmentation spectra obtained from a quadrupole‐time‐of‐flight instrument and ultraviolet‐visible (UV‐vis) spectral data were used to (tentatively) identify 32 phenolic compounds from the analytical CCC fractions. Of the seven isolated compounds, (2S)‐5‐O‐α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosyleriodictyol (3) and (2S)‐5‐O‐α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosyl‐5,7,3′,4′‐tetrahydroxyflavan (4) were newly identified in all plants. The other isolated compounds were identified as (2S)‐5‐O‐α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosylnaringenin (1), R‐neo‐eriocitrin (2), 3‐O‐α‐l‐arabinopyranosyl‐3,4‐dihydroxybenzoic acid (5), 4‐O‐β‐d‐glucopyranosyl‐Z‐4‐hydroxycinnamic acid (6) and 4‐(4′‐O‐β‐d‐glucopyranosyl‐4′‐hydroxy‐3′‐methoxyphenyl)‐2‐butanone (7).
Conclusions
Among the 32 compounds (tentatively) identified, only six were previously identified in Cyclopia pubescens using 1D LC. Most of the isolated compounds were also identified for the first time in Cyclopia spp., improving the knowledge of the minor phenolic compounds of this genus.
Limited separation by one‐dimensional (1D) liquid chromatography (LC) and lack of knowledge about minor phenolic constituents of Cyclopia pubescens provided incentive to develop a comprehensive offline two‐dimensional (2D) normal‐phase‐high performance countercurrent chromatography (NP‐HPCCC) × reversed‐phase‐ultra‐high‐performance liquid chromatography (RP‐UHPLC) method with high orthogonality (81%). This enabled tentative identification of 32 phenolic compounds. The analytical HPCCC method was up‐scaled, fractions pooled based on phenolic sub‐groups and seven compounds were isolated and their structures elucidated. Of these, (2S)‐5‐O‐α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosyleriodictyol (3) and (2S)‐5‐O‐α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosyl‐5,7,3′,4′‐tetrahydroxyflavan (4), were newly identified in all plants.
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