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ABSTRACT: An approach for rapid optimization of ultra-high performance supercritical fluid chromatographic (UHPSFC) gradient by response surface methodology was developed for fast separation of complex crude extracts of the leaves of Rosa sericea. The optimization was performed with Box-Behnken designs and the multicriteria response variables were described using Derringer's desirability. Based on factorial design experiments, five factors were selected for BBDs to optimize the UHPSFC conditions, which led to 46 experiments being performed within 8 hours. An evaporative light scattering detector (ELSD) was used, and quantitative analysis of main components in Rosa sericea samples was employed to evaluate the statistical significance of the parameters on UHPSFC-ELSD analytes response. The results indicated that the optimized UHPSFC-ELSD method is very sensitive with LODs and LOQs below 1.19 μg/mL and 4.55 μg/mL, respectively. The overall intra-day and inter-day variations were less than 3.91% and 6.41%, respectively. The recovery of the method ranged from 95.66%-104.22%, with RSD less than 5.91%. This newly developed UHPSFC-ELSD method was demonstrated to be fast and sensitive in analyzing complex herbal extracts of Traditional Chinese Medicines. This article is protected by copyright. All rights reserved.
Journal of Separation Science 04/2013; · 2.73 Impact Factor
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ABSTRACT: Non-target screening of veterinary drugs using tandem mass spectrometric data was performed on the SmartMass platform. This newly developed software uses the characteristic fragmentation patterns (CFP) to identify chemicals, especially those containing particular substructures. A mixture of 17 sulfonamides was separated by ultra performance liquid chromatography (UPLC), and SmartMass was used to process the tandem mass spectrometry (MS/MS) data acquired on an Orbitrap mass spectrometer. The data were automatically extracted, and each sulfonamide was recognized and analyzed with a prebuilt analysis rule. By using this software, over 98 % of the false candidate structures were eliminated, and all the correct structures were found within the top 10 of the ranking lists. Furthermore, SmartMass could also be used to identify slightly modified contraband drugs and metabolites with simple prebuilt rules.
Journal of the American Society for Mass Spectrometry 03/2013; · 4.00 Impact Factor
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ABSTRACT: Two structurally similar bioactive regioisomers, 3-O-tetradecanoylingenol and 20-O-tetradecanoylingenol, from Euphorbia wallichii presented quite different fragmentation behaviors. Revealing the related fragmentation pathways may improve the efficiency of characterization and identification of such type of compounds.
The two regioisomers were subjected to collision-induced dissociation (CID) on Finnigan LCQ(DECA) and LTQ Orbitrap XL instruments. Based on the CID results, the possible fragmentation pathways were proposed and investigated with density functional theory (DFT) calculations.
Elimination of C(14) H(28) O(2) (tetradecanoic acid) for 3-O-tetradecanoylingenol and the sequential losses of C(4) H(8) (butylene) for 20-O-tetradecanoylingenol were observed in ESI-MS/MS, witnessed also by HR-ESI-MS/MS. The fragmentation pathways were proposed and verified by calculating the activation energy of their transition states by DFT calculations.
Based on the observations, fragmentation pathways for the two regioisomers were proposed and verified by calculating the energy of the reactants, products and the corresponding transition states using DFT. This report should have value in rapid identification of the derivatives of ingenol and other regioisomers in natural products. Copyright © 2012 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry 11/2012; 26(21):2502-8. · 2.79 Impact Factor
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ABSTRACT: Carbohydrates are good source of drugs and play important roles in metabolism processes and cellular interactions in organisms. Distinguishing monosaccharide isomers in saccharide derivates is an important and elementary work in investigating saccharides. It is important to develop a fast, simple and direct method for this purpose, which is described in this study.
Stock solutions of monosaccharide with a concentration of 400 μM and sodium chloride at a concentration of 10 μM were made in water/methanol (50:50, v/v). The samples were subjected to electrospray ionization ion-trap tandem mass spectrometry (ESI-MS) and the detected [2M + Na - H(2)O](+) ions were further investigated by tandem mass spectrometry (MS/MS), followed by applying principal component analysis (PCA) on the obtained MS/MS data sets.
The MS/MS spectra of the [2M + Na - H(2)O](+) ions at m/z 365 for hexoses and m/z 305 for pentoses yielded unambiguous fragment patterns, while rhamnose can be directly identified by its ESI-MS [M + Na](+) ion at m/z 187. PCA showed clustering of MS/MS data of identical monosaccharide samples obtained from different experiments. By using this method, the monosaccharide in daucosterol hydrolysate was successfully identified.
A new strategy was developed for differentiation of the monosaccharides using ESI-MS/MS and PCA. In MS/MS spectra, the [2M + Na - H(2)O](+) ions yielded unambiguous distinction. PCA of the archived MS/MS data sets was applied to demonstrate the spatial resolution of the studied samples. This method presented a simple and reliable way for distinguishing monosaccharides by ESI-MS/MS.
Rapid Communications in Mass Spectrometry 06/2012; 26(11):1259-64. · 2.79 Impact Factor
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ABSTRACT: To manage chemical structures in small laboratories is one of the important daily tasks. Few solutions are available on the internet, and most of them are closed source applications. The open-source applications typically have limited capability and basic cheminformatics functionalities. In this article, we describe an open-source solution to manage chemicals in research groups based on open source and free components. It has a user-friendly interface with the functions of chemical handling and intensive searching.
MyMolDB is a micromolecular database solution that supports exact, substructure, similarity, and combined searching. This solution is mainly implemented using scripting language Python with a web-based interface for compound management and searching. Almost all the searches are in essence done with pure SQL on the database by using the high performance of the database engine. Thus, impressive searching speed has been archived in large data sets for no external Central Processing Unit (CPU) consuming languages were involved in the key procedure of the searching.
MyMolDB is an open-source software and can be modified and/or redistributed under GNU General Public License version 3 published by the Free Software Foundation (Free Software Foundation Inc. The GNU General Public License, Version 3, 2007. Available at: http://www.gnu.org/licenses/gpl.html). The software itself can be found at http://code.google.com/p/mymoldb/.
Journal of Computational Chemistry 10/2011; 32(13):2942-8. · 4.58 Impact Factor
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ABSTRACT: A validated HPLC-DAD-ESI-MS method has been developed to simultaneously quantify 12 bioactive compounds in the seeds of Notopterygium incisum Ting ex H.T. Chang and Notopterygium franchetii H. de Boiss whose rhizomes and roots are widely used as traditional Chinese medicine. This method was validated to be sensitive, precise and accurate and was applied to evaluate the difference in the chemical profiles and contents of these analytes in 37 batches of N. incisum and 31 batches of N. franchetii samples collected from different locations. Principal component analysis showed that the two species were separated into two groups obviously. This study established a validated method for identification of the authenticity of the seeds of N. incisum and N. franchetii and supplied effective guidance for artificial cultivation.
Journal of pharmaceutical and biomedical analysis 07/2011; 56(5):1089-93. · 2.45 Impact Factor
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ABSTRACT: Carboxymethyl konjac glucomannan-chitosan (CKGM-CS) nanocapsules, spontaneously prepared under very mild conditions by electrostatic complexation, were used for immobilizing L-asparaginase. The matrix has semi-permeability to allow the substrate and product to pass through and to keep L-asparaginase in the matrix to prevent leaking. The cell-like hydrogel matrix was prepared in aqueous system without organic solvents and reagents. The process of the preparation does not denature the enzyme and the activity of the immobilized and native enzyme is very similar. The activity, stability, and characters of the enzyme-loaded nanocapsules were studied. The results indicated the immobilized enzyme has better stability and activity in contrast to the native enzyme. These studies may supply a new material for the immobilization of pH and temperature-sensitive enzyme.
International Journal of Pharmaceutics 09/2008; 364(1):102-7. · 3.35 Impact Factor
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ABSTRACT: Carboxymethyl konjac glucomannan (CKGM) grafted methoxy poly(ethylene glycol) (mPEG) (CKGM-g-mPEG) copolymer was prepared by reacting the CKGM with methoxy poly(ethylene glycol) amine in the presence of 1-ethyl-3-[3-(dimethylamino)propyl]-carbodiimide (EDC) and N-hydroxysuccimide (NHS). By varying the mPEG-OCOCH2NH2/CKGM feed ratio, the degree of substitution (DS) of mPEG could be adjusted. The degree of substitution (DS) of mPEG into CKGM was calculated from TGA data. The chemical structure and physical properties of the products were identified by means of FT-IR, 1H NMR, DSC and TGA. Solubility and the viscosity tests showed that CKGM-g-mPEG has better solubility and lower viscosity at low shear frequency as compared to non-pegylated CKGM.
Carbohydrate Polymers.
