Efficient Tool For Separation Research Articles

Integration of offline two-dimensional chromatography and mass defect filtering-based precursor ion list data acquisition for targeted characterization of diterpenoid alkaloids in the lateral roots of Aconitum carmichaelii

The hyphenated technique of offline two-dimensional (2D) chromatography with high resolution mass spectrometry (MS) was an efficient tool for separation and characterization of components in complex systems such as herbal medicines, especially those co-eluting components or isomers. In this study, we constructed the ultra-performance convergence chromatography (UPC2) × reversed phase (RP) chromatographic separation system and developed a mass defect filtering (MDF)-based precursor ion list (PIL) acquisition method to improve the selectivity and sensitivity of this technique, and the systematic characterization of diterpenoid alkaloids in the lateral roots of Aconitum carmichaelii (namely “Fuzi” in Chinese) was used as an example. The constructed offline 2D separation system showed a good orthogonality of 0.77. Besides, the in-house databases for known and predicted C19- and C20-diterpenoid alkaloids were established by molecular design in Compound Discoverer software for MS data matching and filtering, and two MDF windows were further constructed to screen out more potential diterpenoid alkaloids with novel structures and to obtain the PIL (mass range: even values between 298 and 1020 Da, parent mass width: ±100 mDa) for data acquisition by calculating the m/z values of potential ions using mass range and corresponding mass defect in the MDF windows. In addition, an integrative structure interpretation strategy was developed by integrating elemental composition analysis, ring double bond analysis, neutral loss filtering, diagnostic ion filtering and database matching, etc. As a result, a total of 659 components in the lateral roots of A. carmichaelii were exposed and characterized, including 526 potential new compounds. This strategy showed significant advantages in improving the coverage and selectivity of screening, and could also be applied in systematic characterization of components in other herbal medicines.

Residue Characterization from Polishing Granite Submitted to the Hydrocycloning Process

The waste generated in granite processing has caused great social and environmental concern due to the release of its solid effluents into landfills and other places. The recycling and reuse of waste from different industrial processes as new raw materials has been the object of various researches. The use of hydrocyclone in the treatment of residues can represent a very efficient tool for separation and purification of the granite residue. This work aims to characterize and analyse the technological properties of the granite sawdust residues submitted to the hydrocyclone process in comparison with the same residue without going through the hydrocyclone process. The results indicate that the material resulting from this process presented different characteristics from the material without the process, mainly in terms of granulometric distribution and technological properties.

On-line comprehensive two-dimensional liquid chromatography tandem mass spectrometry for the analysis of Curcuma kwangsiensis

A novel online comprehensive two-dimensional liquid chromatography (2DLC) coupled with quadrupole time-of-flight (Q-TOF) mass spectrometry (MS) method is developed for the analysis of Curcuma kwangsiensis (C. kwangsiensis) extract. In this system, a newly developed phenyl/tetrazole sulfoether (PTAS) bonded stationary phase was introduced to construct RPLC×RPLC combined with C18. The unique structure endowed PTAS with very different selectivity from C18, reaching a high orthogonality of 93.2%. Moreover, such a combination settled compatibility issues because of the weaker hydrophobic retaining property of PTAS, thus allowing direct interfacing in online configuration. As a result of coupling with the mass spectrometry, a four-dimensional (4D) data plot was presented, in which 439 peaks (containing positive mode and negative mode) were counted, and 105 compounds were grouped and tentatively identified in C. kwangsiensis extract, including 73 unreported ones. Some novel types of compounds with masses exceeding 500 were discovered for the first time. Besides, compared to one-dimensional liquid chromatography (1DLC), the great resolution power of this system allowed separation of more isomers. These results provide supplementary to the material basis of C. Kwangsiensis and in-depth research should be conducted. The configuration of RPLC×RPLC-Q-TOF MS can be a powerful and efficient tool for separation and characterization of chemical substances in complicated herbal extracts.

Isolation of four high‐purity dammarane saponins from extract of Panax notoginseng by centrifugal partition chromatography coupled with evaporative light scattering detection in one operation

Centrifugal partition chromatography (CPC), as a continuous liquid-liquid partition chromatography with no solid support matrix, combined with evaporative light scattering detection (ELSD) was employed for systematic separation and purification of weak-chromophoric saponins from a highly valued and important traditional Chinese herbal medicine, Panax notoginseng. To separate and isolate high-purity saponins from extract of Panax notoginseng using CPC-ELSD with a simple and low toxicity solvent system. Samples were preparaed by extracting the root material with acetone, treated with n-butanol and then freeze-dried. CPC-ELSD was applied in the separation and detection of notoginsenoside and ginsenosides from extract of Panax notoginseng using a solvent system composed of ethyl acetate-n-butanol-water (1:1:2, v/v/v). The saponins were analysed and identified by their retention time with high-performance liquid chromatography (HPLC) coupled with ELSD, as well as electrospray ionisation tandem mass spectrometry (ESI-MS(n) ) in the negative and positive ion modes with the authentic standards. A total of 9.6 mg of notoginsenoside R₁, 67.8 mg of ginsenoside Rg₁, 2.3 mg of Re and 286.5 mg of Rb₁ were purified from 487.2 mg of n-butanol extract of P. notoginseng. The purities of obtained saponins in a single run were assessed to be over 98% by HPLC-ELSD. CPC-ELSD was proved to be a very fast and efficient tool for separation of high-purity dammarane saponins.

Towards the Chemical Synthesis of Proteins

AbstractThe chemical total synthesis of proteins using solid supports has made great progress. It is therefore becoming a reality whatE. Fischeralready predicted in 1902: “I foresee the time when physiological chemistry… is able to prepare synthetic enzymes.” The synthesis of peptides of up to 20 amino acids by the well‐established solid‐phase procedure on polymeric supports (SPPS) has made great progress through the development of newer supports. At the same time, methods have emerged which facilitate the separation and characterization of peptides, thus allowing optimization of the synthesis of pure materials. The new supports which enable one to synthesize peptides by a rapid continuous flow procedure are characterized by hydrophilicity, beads of approximately equal size, similar swelling properties in the solvents used for peptide synthesis, and stability at high pressure. With graft copolymers of weakly cross‐linked polystyrene and linear polyethylene glycol (PEG), the synthetic cycle for coupling of one amino acid can routinely be reduced to 10–20 min with a concomitant higher yield. With beads of monodispersed graft copolymer of 10 μm diameter, a synthetic cycle can, in principle, be shortened to 1–5 min. By utilizing this high‐speed solid‐phase procedure, larger peptides up to the size of proteins could also be prepared in a few hours. With newer mass spectroscopic methods such as ion‐spray mass spectrometry, peptides of up to a molecular mass of 100 kDa can be characterized, and with the advent of capillary electrophoresis, another very efficient separation tool, besides HPLC, is at our disposal.