Systematic profiling and comparison of the lipidomes from Panax ginseng, P. quinquefolius, and P. notoginseng by ultrahigh performance supercritical fluid chromatography/high-resolution mass spectrometry and ion mobility-derived collision cross section measurement

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548
Author(s): Xiaojian Shi, Wenzhi Yang, Shi Qiu, Jinjun Hou, Wanying Wu, Dean Guo
Lipidomics currently is still confronted with challenges from chromatographic separation and lipids identification. Here we report a lipidomics platform by integrating ultrahigh performance supercritical fluid chromatography/quadrupole time-of-flight mass spectrometry (UHPSFC/QTOF-MS) and collision cross section (CCS) measurement using ion mobility spectroscopy/time-of-flight mass spectrometry (IMS/QTOF-MS), aiming to enhance the profiling performance and identification reliability of lipids. The lipidomes extracted from three congeneric Panax species (P. ginseng, P. quinquefolius, and P. notoginseng) by methyl tert-butyl ether are comprehensively profiled and compared by use of this platform. A potent UHPSFC/QTOF-MS approach was developed on a 1.7-μm particles packed Torus 2-PIC column using CH3OH (in CO2) as a modifier and CH3OH/0.2 mM ammonium acetate as the makeup liquid, enabling well resolution of six lipid subclasses by both positive and negative MSE modes. In contrast to the reversed-phase chromatography, “normal-phase” like elution order and better resolution of polar lipids and some lipid isomers were achieved by UHPSFC separation. Pattern recognition chemometric analysis of 60 batches of Ginseng samples ultimately unveiled 24 lipid markers, of which triacylglycerols were the most important. Aside from the automated MS database searching against HMDB and LIPID MAPS, the application of CCS retrieval or CCS prediction improved lipid identification by reducing the possible hits. In conclusion, this integral platform can significantly improve the chromatographic separation and the reliability of lipids identification in lipidomics studies. It is the first report that systematically compares the lipidomic difference of three reputable Panax species, providing useful information for their quality control in addition to ginsenoside analysis.

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548

Author(s): Xiaojian Shi, Wenzhi Yang, Shi Qiu, Jinjun Hou, Wanying Wu, Dean Guo

Lipidomics currently is still confronted with challenges from chromatographic separation and lipids identification. Here we report a lipidomics platform by integrating ultrahigh performance supercritical fluid chromatography/quadrupole time-of-flight mass spectrometry (UHPSFC/QTOF-MS) and collision cross section (CCS) measurement using ion mobility spectroscopy/time-of-flight mass spectrometry (IMS/QTOF-MS), aiming to enhance the profiling performance and identification reliability of lipids. The lipidomes extracted from three congeneric Panax species (P. ginseng, P. quinquefolius, and P. notoginseng) by methyl tert-butyl ether are comprehensively profiled and compared by use of this platform. A potent UHPSFC/QTOF-MS approach was developed on a 1.7-μm particles packed Torus 2-PIC column using CH3OH (in CO2) as a modifier and CH3OH/0.2 mM ammonium acetate as the makeup liquid, enabling well resolution of six lipid subclasses by both positive and negative MSE modes. In contrast to the reversed-phase chromatography, “normal-phase” like elution order and better resolution of polar lipids and some lipid isomers were achieved by UHPSFC separation. Pattern recognition chemometric analysis of 60 batches of Ginseng samples ultimately unveiled 24 lipid markers, of which triacylglycerols were the most important. Aside from the automated MS database searching against HMDB and LIPID MAPS, the application of CCS retrieval or CCS prediction improved lipid identification by reducing the possible hits. In conclusion, this integral platform can significantly improve the chromatographic separation and the reliability of lipids identification in lipidomics studies. It is the first report that systematically compares the lipidomic difference of three reputable Panax species, providing useful information for their quality control in addition to ginsenoside analysis.





Feasibility study for high-resolution multi-component separation of protein mixture using a cation-exchange cuboid packed-bed device

Publication date: 11 May 2018
Source:Journal of Chromatography A, Volume 1549
Author(s): Guoqiang Chen, Alisha Gerrior, Raja Ghosh
In recent papers we have discussed the optimization of design and operating conditions for cuboid packed-bed device for chromatographic separations. The efficiency metrics used in these studies included the number of theoretical plates per unit bed height as well as attributes of flow-through and eluted peaks. These studies were carried out using equivalent columns as benchmarks. The cuboid packed-bed devices consistently outperformed the columns in terms of the above metrics. The current study examines how well, or indeed if at all these superior efficiency metrics translate to superiority in multi-component protein separation. Cation exchange resin was examined in the current study using appropriate multi-component model protein system which was chosen with close isoelectric points to make the separation challenging. Effects of operating and experimental parameters such as flow rate, loop size and linear gradient length on separation performance were systematically investigated. Separation metrics examined included peak width, tailing factor, asymmetry factor and resolution of separated protein peaks. The results obtained showed that the cation exchange cuboid packed-bed device significantly outperformed its equivalent commercial column (e.g., the number of theoretical plates per unit bed height was 8636/m for the cuboid packed-bed device as opposed to 1480/m for the column at a flow rate of 0.5 mL/min). The difference in efficiency was particularly high at lower flow rate and when shorter gradients were employed. The results suggest that the cuboid packed-bed devices could potentially have promising application in preparative separations such as biopharmaceutical purifications.

Publication date: 11 May 2018
Source:Journal of Chromatography A, Volume 1549

Author(s): Guoqiang Chen, Alisha Gerrior, Raja Ghosh

In recent papers we have discussed the optimization of design and operating conditions for cuboid packed-bed device for chromatographic separations. The efficiency metrics used in these studies included the number of theoretical plates per unit bed height as well as attributes of flow-through and eluted peaks. These studies were carried out using equivalent columns as benchmarks. The cuboid packed-bed devices consistently outperformed the columns in terms of the above metrics. The current study examines how well, or indeed if at all these superior efficiency metrics translate to superiority in multi-component protein separation. Cation exchange resin was examined in the current study using appropriate multi-component model protein system which was chosen with close isoelectric points to make the separation challenging. Effects of operating and experimental parameters such as flow rate, loop size and linear gradient length on separation performance were systematically investigated. Separation metrics examined included peak width, tailing factor, asymmetry factor and resolution of separated protein peaks. The results obtained showed that the cation exchange cuboid packed-bed device significantly outperformed its equivalent commercial column (e.g., the number of theoretical plates per unit bed height was 8636/m for the cuboid packed-bed device as opposed to 1480/m for the column at a flow rate of 0.5 mL/min). The difference in efficiency was particularly high at lower flow rate and when shorter gradients were employed. The results suggest that the cuboid packed-bed devices could potentially have promising application in preparative separations such as biopharmaceutical purifications.





Development of an analytical method for urocanic acid isomers in fish based on reactive extraction cleanup and chaotropic chromatography techniques

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548
Author(s): Jian-Jun Zhong, Ningbo Liao, Mingfeng He, Yunfeng Pu, Donghong Liu
Urocanic acid (UA), existing in trans- or cis-isoform, is of fairly recent interest to food researchers because of its potential public health hazards of scombrotoxicity and immunotoxicity, as well as associating with fish spoilage. This work is among the first efforts to study the analytical chemistry of UA in fish. With 0.6 M perchloric acid UA was extracted, and co-extracted fish matrix components were efficiently removed through a reactive extraction of UA. The optimum conditions for the reactive extraction, which allowed an 80% recovery of UA, were sample pH adjustment to 9, twice extractions with 32% (w/w) di (2-ethylhexyl) phosphate in hexanol, and a back-extraction with 0.1 M hydrochloric acid at 1:1 phase ratio. A chaotropic hexafluorophosphate salt was added to acidic water-acetonitrile mobile phases to improve the reversed-phase chromatography of UA, which otherwise was poorly retained. Optimum separation conditions were obtained for fish samples and enabled a fast (10 min), convenient-to-use chromatography that clearly outperforms cumbersome legacy ion-pair chromatography. Intended for routine use in our laboratory, the proposed method passed an in-house validation test for linearity, matrix effect (on reactive extraction), accuracy, precision, and detectability.

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548

Author(s): Jian-Jun Zhong, Ningbo Liao, Mingfeng He, Yunfeng Pu, Donghong Liu

Urocanic acid (UA), existing in trans- or cis-isoform, is of fairly recent interest to food researchers because of its potential public health hazards of scombrotoxicity and immunotoxicity, as well as associating with fish spoilage. This work is among the first efforts to study the analytical chemistry of UA in fish. With 0.6 M perchloric acid UA was extracted, and co-extracted fish matrix components were efficiently removed through a reactive extraction of UA. The optimum conditions for the reactive extraction, which allowed an 80% recovery of UA, were sample pH adjustment to 9, twice extractions with 32% (w/w) di (2-ethylhexyl) phosphate in hexanol, and a back-extraction with 0.1 M hydrochloric acid at 1:1 phase ratio. A chaotropic hexafluorophosphate salt was added to acidic water-acetonitrile mobile phases to improve the reversed-phase chromatography of UA, which otherwise was poorly retained. Optimum separation conditions were obtained for fish samples and enabled a fast (10 min), convenient-to-use chromatography that clearly outperforms cumbersome legacy ion-pair chromatography. Intended for routine use in our laboratory, the proposed method passed an in-house validation test for linearity, matrix effect (on reactive extraction), accuracy, precision, and detectability.





Multi-class multi-residue analysis of veterinary drugs in meat using enhanced matrix removal lipid cleanup and liquid chromatography-tandem mass spectrometry

Publication date: 11 May 2018
Source:Journal of Chromatography A, Volume 1549
Author(s): Limian Zhao, Derick Lucas, David Long, Bruce Richter, Joan Stevens
This study presents the development and validation of a quantitation method for the analysis of multi-class, multi-residue veterinary drugs using lipid removal cleanup cartridges, enhanced matrix removal lipid (EMR-Lipid), for different meat matrices by liquid chromatography tandem mass spectrometry detection. Meat samples were extracted using a two-step solid-liquid extraction followed by pass-through sample cleanup. The method was optimized based on the buffer and solvent composition, solvent additive additions, and EMR-Lipid cartridge cleanup. The developed method was then validated in five meat matrices, porcine muscle, bovine muscle, bovine liver, bovine kidney and chicken liver to evaluate the method performance characteristics, such as absolute recoveries and precision at three spiking levels, calibration curve linearity, limit of quantitation (LOQ) and matrix effect. The results showed that >90% of veterinary drug analytes achieved satisfactory recovery results of 60–120%. Over 97% analytes achieved excellent reproducibility results (relative standard deviation (RSD) < 20%), and the LOQs were 1–5 μg/kg in the evaluated meat matrices. The matrix co-extractive removal efficiency by weight provided by EMR-lipid cartridge cleanup was 42–58% in samples. The post column infusion study showed that the matrix ion suppression was reduced for samples with the EMR-Lipid cartridge cleanup. The reduced matrix ion suppression effect was also confirmed with <15% frequency of compounds with significant quantitative ion suppression (>30%) for all tested veterinary drugs in all of meat matrices. The results showed that the two-step solid-liquid extraction provides efficient extraction for the entire spectrum of veterinary drugs, including the difficult classes such as tetracyclines, beta-lactams etc. EMR-Lipid cartridges after extraction provided efficient sample cleanup with easy streamlined protocol and minimal impacts on analytes recovery, improving method reliability and consistency.

Publication date: 11 May 2018
Source:Journal of Chromatography A, Volume 1549

Author(s): Limian Zhao, Derick Lucas, David Long, Bruce Richter, Joan Stevens

This study presents the development and validation of a quantitation method for the analysis of multi-class, multi-residue veterinary drugs using lipid removal cleanup cartridges, enhanced matrix removal lipid (EMR-Lipid), for different meat matrices by liquid chromatography tandem mass spectrometry detection. Meat samples were extracted using a two-step solid-liquid extraction followed by pass-through sample cleanup. The method was optimized based on the buffer and solvent composition, solvent additive additions, and EMR-Lipid cartridge cleanup. The developed method was then validated in five meat matrices, porcine muscle, bovine muscle, bovine liver, bovine kidney and chicken liver to evaluate the method performance characteristics, such as absolute recoveries and precision at three spiking levels, calibration curve linearity, limit of quantitation (LOQ) and matrix effect. The results showed that >90% of veterinary drug analytes achieved satisfactory recovery results of 60–120%. Over 97% analytes achieved excellent reproducibility results (relative standard deviation (RSD) < 20%), and the LOQs were 1–5 μg/kg in the evaluated meat matrices. The matrix co-extractive removal efficiency by weight provided by EMR-lipid cartridge cleanup was 42–58% in samples. The post column infusion study showed that the matrix ion suppression was reduced for samples with the EMR-Lipid cartridge cleanup. The reduced matrix ion suppression effect was also confirmed with <15% frequency of compounds with significant quantitative ion suppression (>30%) for all tested veterinary drugs in all of meat matrices. The results showed that the two-step solid-liquid extraction provides efficient extraction for the entire spectrum of veterinary drugs, including the difficult classes such as tetracyclines, beta-lactams etc. EMR-Lipid cartridges after extraction provided efficient sample cleanup with easy streamlined protocol and minimal impacts on analytes recovery, improving method reliability and consistency.





A monolithic column based on covalent cross-linked polymer gels for online extraction and analysis of trace aflatoxins in food sample

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548
Author(s): Tianfu Wei, Zhengyi Chen, Gongke Li, Zhuomin Zhang
Aflatoxins are highly toxic mycotoxin contamination, which pose serious food safety incidents. It is very important to precisely and rapidly determine trace aflatoxins in food. In this study, we designed porous monolithic column based on covalent cross-linked polymer gels for online extraction and analysis of trace aflatoxins in food samples with complicated matrices coupled with high-performance liquid chromatography-ultraviolet detector (HPLC-UV). The prepared monolithic column showed excellent enrichment performance due to its good permeability, good reproducibility and long life span. The study of adsorption mechanism suggested that the excellent enrichment performance of this monolithic column was attributed to the multiple effect of π-π stacking interaction, hydrophobic effect and steric effect. When the online analytical method was applied for the determine of trace aflatoxins in real food samples, aflatoxins G1 and aflatoxins B1 could be actually found in one positive bean sauce sample and quantified to be 32.8 and 26.4 μg/kg, respectively. Aflatoxins G1 in one bean sample could be also found and quantified to be 25.9 μg/kg. The low detection limits of the developed method were achieved in range of 0.08-0.2 μg/kg. And the recoveries for spiked samples were in range from 76.1 to 113% with RSDs of 1.1-9.6%. The developed method was proved to be a promising method for online enrichment and analysis of trace aflatoxins in complicated food samples.

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548

Author(s): Tianfu Wei, Zhengyi Chen, Gongke Li, Zhuomin Zhang

Aflatoxins are highly toxic mycotoxin contamination, which pose serious food safety incidents. It is very important to precisely and rapidly determine trace aflatoxins in food. In this study, we designed porous monolithic column based on covalent cross-linked polymer gels for online extraction and analysis of trace aflatoxins in food samples with complicated matrices coupled with high-performance liquid chromatography-ultraviolet detector (HPLC-UV). The prepared monolithic column showed excellent enrichment performance due to its good permeability, good reproducibility and long life span. The study of adsorption mechanism suggested that the excellent enrichment performance of this monolithic column was attributed to the multiple effect of π-π stacking interaction, hydrophobic effect and steric effect. When the online analytical method was applied for the determine of trace aflatoxins in real food samples, aflatoxins G1 and aflatoxins B1 could be actually found in one positive bean sauce sample and quantified to be 32.8 and 26.4 μg/kg, respectively. Aflatoxins G1 in one bean sample could be also found and quantified to be 25.9 μg/kg. The low detection limits of the developed method were achieved in range of 0.08-0.2 μg/kg. And the recoveries for spiked samples were in range from 76.1 to 113% with RSDs of 1.1-9.6%. The developed method was proved to be a promising method for online enrichment and analysis of trace aflatoxins in complicated food samples.





Development of a fast and simple gas chromatographic protocol based on the combined use of alkyl chloroformate and solid phase microextraction for the assay of polyamines in human urine

Publication date: 11 May 2018
Source:Journal of Chromatography A, Volume 1549
Author(s): Attilio Naccarato, Rosangela Elliani, Brunella Cavaliere, Giovanni Sindona, Antonio Tagarelli
Polyamines are aliphatic amines with low molecular weight that are widely recognized as one of the most important cancer biomarkers for early diagnosis and treatment. The goal of the work herein presented is the development of a rapid and simple method for the quantification of free polyamines (i.e., putrescine, cadaverine, spermidine, spermine) and N-monoacetylated polyamines (i.e., N1-Acetylspermidine, N8-Acetylspermidine, and N1-Acetylspermine) in human urine. A preliminary derivatization with propyl chloroformate combined with the use of solid phase microextraction (SPME) allowed for an easy and automatable protocol involving minimal sample handling and no consumption of organic solvents. The affinity of the analytes toward five commercial SPME coatings was evaluated in univariate mode, and the best result in terms of analyte extraction was achieved using the divinylbenzene/carboxen/polydimethylsiloxane fiber. The variables affecting the performance of SPME analysis were optimized by the multivariate approach of experimental design and, in particular, using a central composite design (CCD). The optimal working conditions in terms of response values are the following: extraction temperature 40 °C, extraction time of 15 min and no addition of NaCl. Analyses were carried out by gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) in selected reaction monitoring (SRM) acquisition mode. The developed method was validated according to the guidelines issued by the Food and Drug Administration (FDA). The satisfactory performances reached in terms of linearity, sensitivity (LOQs between 0.01 and 0.1 μg/mL), matrix effect (68–121%), accuracy, and precision (inter-day values between −24% and +16% and in the range 3.3–28.4%, respectively) make the proposed protocol suitable to be adopted for quantification of these important biomarkers in urine samples.

Publication date: 11 May 2018
Source:Journal of Chromatography A, Volume 1549

Author(s): Attilio Naccarato, Rosangela Elliani, Brunella Cavaliere, Giovanni Sindona, Antonio Tagarelli

Polyamines are aliphatic amines with low molecular weight that are widely recognized as one of the most important cancer biomarkers for early diagnosis and treatment. The goal of the work herein presented is the development of a rapid and simple method for the quantification of free polyamines (i.e., putrescine, cadaverine, spermidine, spermine) and N-monoacetylated polyamines (i.e., N 1-Acetylspermidine, N 8-Acetylspermidine, and N 1-Acetylspermine) in human urine. A preliminary derivatization with propyl chloroformate combined with the use of solid phase microextraction (SPME) allowed for an easy and automatable protocol involving minimal sample handling and no consumption of organic solvents. The affinity of the analytes toward five commercial SPME coatings was evaluated in univariate mode, and the best result in terms of analyte extraction was achieved using the divinylbenzene/carboxen/polydimethylsiloxane fiber. The variables affecting the performance of SPME analysis were optimized by the multivariate approach of experimental design and, in particular, using a central composite design (CCD). The optimal working conditions in terms of response values are the following: extraction temperature 40 °C, extraction time of 15 min and no addition of NaCl. Analyses were carried out by gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) in selected reaction monitoring (SRM) acquisition mode. The developed method was validated according to the guidelines issued by the Food and Drug Administration (FDA). The satisfactory performances reached in terms of linearity, sensitivity (LOQs between 0.01 and 0.1 μg/mL), matrix effect (68–121%), accuracy, and precision (inter-day values between −24% and +16% and in the range 3.3–28.4%, respectively) make the proposed protocol suitable to be adopted for quantification of these important biomarkers in urine samples.





Reversed phase ion-pair chromatographic separation of sugar alcohols by complexation with molybdate ion

Publication date: 27 April 2018
Source:Journal of Chromatography A, Volume 1547
Author(s): Tomoko Kemmei, Shuji Kodama, Atsushi Yamamoto, Yoshinori Inoue, Kazuichi Hayakawa
In this study, we developed a simple and sensitive reversed phase ion-pair chromatographic method for the analysis of C4-C6 sugar alcohols. The method is based on the on-line complexation of sugar alcohols with molybdate ion. The resulting dinuclear anionic complexes can be separated on a reversed-phase C18 column using tetrabutylammonium chloride as an ion-pairing reagent. The mobile phase (pH 3.1) consisted of 0.1 mM disodium molybdate, 1 mM hydrochloric acid and 0.4 mM tetrabutylammonium chloride – 10% v/v methanol. By complexing with molybdate ion, sugar alcohols can be detected by their UV absorption at 247 nm with high resolution and sensitivity. The quantification limits of the examined sugar alcohols calculated at S/N = 10 were 0.1 mM for erythritol and xylitol and 0.01 mM for arabitol, sorbitol, mannitol and dulcitol. The detector response was linear over three orders of magnitude of sugar alcohol concentration. The proposed method was successfully applied to measure sugar alcohols in health drinks, eyedrops and mouthwashes.

Publication date: 27 April 2018
Source:Journal of Chromatography A, Volume 1547

Author(s): Tomoko Kemmei, Shuji Kodama, Atsushi Yamamoto, Yoshinori Inoue, Kazuichi Hayakawa

In this study, we developed a simple and sensitive reversed phase ion-pair chromatographic method for the analysis of C4-C6 sugar alcohols. The method is based on the on-line complexation of sugar alcohols with molybdate ion. The resulting dinuclear anionic complexes can be separated on a reversed-phase C18 column using tetrabutylammonium chloride as an ion-pairing reagent. The mobile phase (pH 3.1) consisted of 0.1 mM disodium molybdate, 1 mM hydrochloric acid and 0.4 mM tetrabutylammonium chloride – 10% v/v methanol. By complexing with molybdate ion, sugar alcohols can be detected by their UV absorption at 247 nm with high resolution and sensitivity. The quantification limits of the examined sugar alcohols calculated at S/N = 10 were 0.1 mM for erythritol and xylitol and 0.01 mM for arabitol, sorbitol, mannitol and dulcitol. The detector response was linear over three orders of magnitude of sugar alcohol concentration. The proposed method was successfully applied to measure sugar alcohols in health drinks, eyedrops and mouthwashes.





Ion exchange column capacities. Predicting retention behavior of open tubular columns coated with the same phase

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550
Author(s): Weixiong Huang, Christopher A. Pohl, Purnendu K. Dasgupta
We discuss the reported capacities of available packed ion exchange columns and the different methods used for their measurement. We outline basic considerations related to both packed and open tubular columns based on ion exchange latex particles.There is a large body of information covering the retention behavior of packed ion exchange columns based on ion exchange latex particles. We propose a parameter γiex, which is the ion exchange capacity of a column (packed or open tubular) per unit liquid volume present in the column (including accessible volume within pores) and show that the retention factor for any given ion is directly related to γiex. On this basis, if based on the same type of latex, the behavior of one type of column can be reasonably predicted from the known behavior of the other, even when the absolute capacities differ by more than 5 orders of magnitude.

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550

Author(s): Weixiong Huang, Christopher A. Pohl, Purnendu K. Dasgupta

We discuss the reported capacities of available packed ion exchange columns and the different methods used for their measurement. We outline basic considerations related to both packed and open tubular columns based on ion exchange latex particles. There is a large body of information covering the retention behavior of packed ion exchange columns based on ion exchange latex particles. We propose a parameter γ iex , which is the ion exchange capacity of a column (packed or open tubular) per unit liquid volume present in the column (including accessible volume within pores) and show that the retention factor for any given ion is directly related to γ iex . On this basis, if based on the same type of latex, the behavior of one type of column can be reasonably predicted from the known behavior of the other, even when the absolute capacities differ by more than 5 orders of magnitude.





In-line Fourier-transform infrared spectroscopy as a versatile process analytical technology for preparative protein chromatography

Publication date: 27 April 2018
Source:Journal of Chromatography A, Volume 1547
Author(s): Steffen Großhans, Matthias Rüdt, Adrian Sanden, Nina Brestrich, Josefine Morgenstern, Stefan Heissler, Jürgen Hubbuch
Fourier-transform infrared spectroscopy (FTIR) is a well-established spectroscopic method in the analysis of small molecules and protein secondary structure. However, FTIR is not commonly applied for in-line monitoring of protein chromatography. Here, the potential of in-line FTIR as a process analytical technology (PAT) in downstream processing was investigated in three case studies addressing the limits of currently applied spectroscopic PAT methods. A first case study exploited the secondary structural differences of monoclonal antibodies (mAbs) and lysozyme to selectively quantify the two proteins with partial least squares regression (PLS) giving root mean square errors of cross validation (RMSECV) of 2.42 g/l and 1.67 g/l, respectively. The corresponding Q2 values are 0.92 and, respectively, 0.99, indicating robust models in the calibration range. Second, a process separating lysozyme and PEGylated lysozyme species was monitored giving an estimate of the PEGylation degree of currently eluting species with RMSECV of 2.35 g/l for lysozyme and 1.24 g/l for PEG with Q2 of 0.96 and 0.94, respectively. Finally, Triton X-100 was added to a feed of lysozyme as a typical process-related impurity. It was shown that the species could be selectively quantified from the FTIR 3D field without PLS calibration. In summary, the proposed PAT tool has the potential to be used as a versatile option for monitoring protein chromatography. It may help to achieve a more complete implementation of the PAT initiative by mitigating limitations of currently used techniques.

Graphical abstract

image

Publication date: 27 April 2018
Source:Journal of Chromatography A, Volume 1547

Author(s): Steffen Großhans, Matthias Rüdt, Adrian Sanden, Nina Brestrich, Josefine Morgenstern, Stefan Heissler, Jürgen Hubbuch

Fourier-transform infrared spectroscopy (FTIR) is a well-established spectroscopic method in the analysis of small molecules and protein secondary structure. However, FTIR is not commonly applied for in-line monitoring of protein chromatography. Here, the potential of in-line FTIR as a process analytical technology (PAT) in downstream processing was investigated in three case studies addressing the limits of currently applied spectroscopic PAT methods. A first case study exploited the secondary structural differences of monoclonal antibodies (mAbs) and lysozyme to selectively quantify the two proteins with partial least squares regression (PLS) giving root mean square errors of cross validation (RMSECV) of 2.42 g/l and 1.67 g/l, respectively. The corresponding Q 2 values are 0.92 and, respectively, 0.99, indicating robust models in the calibration range. Second, a process separating lysozyme and PEGylated lysozyme species was monitored giving an estimate of the PEGylation degree of currently eluting species with RMSECV of 2.35 g/l for lysozyme and 1.24 g/l for PEG with Q 2 of 0.96 and 0.94, respectively. Finally, Triton X-100 was added to a feed of lysozyme as a typical process-related impurity. It was shown that the species could be selectively quantified from the FTIR 3D field without PLS calibration. In summary, the proposed PAT tool has the potential to be used as a versatile option for monitoring protein chromatography. It may help to achieve a more complete implementation of the PAT initiative by mitigating limitations of currently used techniques.

Graphical abstract

image




Enantioselective determination of aspartate and glutamate in biological samples by ultrasonic-assisted derivatization coupled with capillary electrophoresis and linked to Alzheimer’s disease progression

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550
Author(s): Ya-Hui Hsieh, Fang-Yi Liao, Yuan-Han Yang, Jing-Ru Weng, Su-Hwei Chen, Chia-Hsien Feng
A simple cyclodextrin-mediated capillary zone electrophoresis method equipped with a laser-induced fluorescence detector was developed for chiral analysis of the excitatory amino acids aspartate (Asp) and glutamate (Glu). Plasma and cerebrospinal fluid (CSF) samples were pretreated with centrifugal filter devices before analysis to remove high-molecular-weight proteins (molecular weight cut-off: 3000) and then derivatized using 10 mM 6-carboxyfluorescein N-hydroxysuccinimide ester in DMSO under sonication at 25 °C for 2 h. After the derivatization reaction, reacted samples were diluted 100-fold with 5-([4,6-dichlorotriazin-2-yl]amino)fluorescein hydrochloride (DTAF) solution and then hydrodynamically subjected to capillary electrophoresis (0.5 psi for 5 s, injection volume 8.27 nL). The separation buffer consisted of 50 mM borate buffer (pH 9.0) with 6 mM γ-CD and 0.1% polyvinylpyrrolidone, and the separation voltage was set at 20 kV. In the linearity calculations for the determination of d/l-Asp and d/l-Glu in plasma and CSF, a standard addition method was utilized to spike solutions with 0–20.0 μg mL−1l-Glu and 0–2.0 μg mL−1d-Glu and d/l-Asp to construct calibration curves. Correlation coefficients were above 0.998 for every analyte. The limits of detection (S/N = 3) for d/l-Asp and d/l-Glu standard solutions were 0.85–0.96 μg mL−1. The proposed method was applied successfully to determine d/l-Asp and d/l-Glu concentrations in the plasma and CSF samples of 26 patients with Alzheimer’s disease (AD), and the association between these concentrations and disease severity was investigated. Statistical analysis showed a moderately negative correlation (r = −0.158) between plasma l-Asp concentration and AD severity.

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550

Author(s): Ya-Hui Hsieh, Fang-Yi Liao, Yuan-Han Yang, Jing-Ru Weng, Su-Hwei Chen, Chia-Hsien Feng

A simple cyclodextrin-mediated capillary zone electrophoresis method equipped with a laser-induced fluorescence detector was developed for chiral analysis of the excitatory amino acids aspartate (Asp) and glutamate (Glu). Plasma and cerebrospinal fluid (CSF) samples were pretreated with centrifugal filter devices before analysis to remove high-molecular-weight proteins (molecular weight cut-off: 3000) and then derivatized using 10 mM 6-carboxyfluorescein N-hydroxysuccinimide ester in DMSO under sonication at 25 °C for 2 h. After the derivatization reaction, reacted samples were diluted 100-fold with 5-([4,6-dichlorotriazin-2-yl]amino)fluorescein hydrochloride (DTAF) solution and then hydrodynamically subjected to capillary electrophoresis (0.5 psi for 5 s, injection volume 8.27 nL). The separation buffer consisted of 50 mM borate buffer (pH 9.0) with 6 mM γ-CD and 0.1% polyvinylpyrrolidone, and the separation voltage was set at 20 kV. In the linearity calculations for the determination of d/l-Asp and d/l-Glu in plasma and CSF, a standard addition method was utilized to spike solutions with 0–20.0 μg mL−1 l-Glu and 0–2.0 μg mL−1 d-Glu and d/l-Asp to construct calibration curves. Correlation coefficients were above 0.998 for every analyte. The limits of detection (S/N = 3) for d/l-Asp and d/l-Glu standard solutions were 0.85–0.96 μg mL−1. The proposed method was applied successfully to determine d/l-Asp and d/l-Glu concentrations in the plasma and CSF samples of 26 patients with Alzheimer’s disease (AD), and the association between these concentrations and disease severity was investigated. Statistical analysis showed a moderately negative correlation (r = −0.158) between plasma l-Asp concentration and AD severity.





Fabrication of a high selectivity magnetic solid phase extraction adsorbent based on β-cyclodextrin and application for recognition of plant growth regulators

Publication date: 27 April 2018
Source:Journal of Chromatography A, Volume 1547
Author(s): Jiuyan Chen, Shurui Cao, Ming Zhu, Cunxian Xi, Lei Zhang, Xianliang Li, Guomin Wang, Yuantao Zhou, Zhiqiong Chen
An adsorbent, consisting of silica-coated Fe3O4 grafted graphene oxide and β-cyclodextrin (Fe3O4@SiO2/GO/β-CD), which possessed the merits of antioxidation, superparamagnetism, high surface area, high supramolecular recognition and environment friendly, was successfully fabricated. Considering the synergy between β-CD and graphene oxide in adsorption mechanism, the synthesized adsorbent could grasp compounds especially with aromatic structures through π-π interaction, hydrophobic interaction and host-guest inclusion complex forming. Based on the advantages, a magnetic solid phase extraction (MSPE) method for 9 PGRs using Fe3O4@SiO2/GO/β-CD as adsorbents was developed in this study. The characterizations of Fe3O4@SiO2/GO/β-CD were performed on Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), CHNS/O elemental analyzer, scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Under the optimal MSPE condition, the Fe3O4@SiO2/GO/β-CD exhibited selectivity capability toward 9 PGRs when compared with Fe3O4@SiO2/GO. Meanwhile, the selectivity capability of Fe3O4@SiO2/GO/β-CD was higher than that of Fe3O4@SiO2/GO/α-CD except for 4-FPA. When the developed MSPE procedure was coupled with ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) to quantitative analysis of 9 PGRs, linearities ranging from 2 to 50 μg/kg were achieved for 9 PGRs with the correlation coefficients (r2) in the range of 0.9975-0.9999. The limits of detection (LODs) for 9 analytes varied from 0.04 to 0.29 μg/kg. Finally, the proposed technique was applied to analyze PGRs residues in mutiple vegetable samples.

Publication date: 27 April 2018
Source:Journal of Chromatography A, Volume 1547

Author(s): Jiuyan Chen, Shurui Cao, Ming Zhu, Cunxian Xi, Lei Zhang, Xianliang Li, Guomin Wang, Yuantao Zhou, Zhiqiong Chen

An adsorbent, consisting of silica-coated Fe3O4 grafted graphene oxide and β-cyclodextrin (Fe3O4@SiO2/GO/β-CD), which possessed the merits of antioxidation, superparamagnetism, high surface area, high supramolecular recognition and environment friendly, was successfully fabricated. Considering the synergy between β-CD and graphene oxide in adsorption mechanism, the synthesized adsorbent could grasp compounds especially with aromatic structures through π-π interaction, hydrophobic interaction and host-guest inclusion complex forming. Based on the advantages, a magnetic solid phase extraction (MSPE) method for 9 PGRs using Fe3O4@SiO2/GO/β-CD as adsorbents was developed in this study. The characterizations of Fe3O4@SiO2/GO/β-CD were performed on Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), CHNS/O elemental analyzer, scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Under the optimal MSPE condition, the Fe3O4@SiO2/GO/β-CD exhibited selectivity capability toward 9 PGRs when compared with Fe3O4@SiO2/GO. Meanwhile, the selectivity capability of Fe3O4@SiO2/GO/β-CD was higher than that of Fe3O4@SiO2/GO/α-CD except for 4-FPA. When the developed MSPE procedure was coupled with ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) to quantitative analysis of 9 PGRs, linearities ranging from 2 to 50 μg/kg were achieved for 9 PGRs with the correlation coefficients (r2) in the range of 0.9975-0.9999. The limits of detection (LODs) for 9 analytes varied from 0.04 to 0.29 μg/kg. Finally, the proposed technique was applied to analyze PGRs residues in mutiple vegetable samples.





Gold nanoparticles dispersion stability under dynamic coating conditions in capillary zone electrophoresis

Publication date: 18 May 2018 Source:Journal of Chromatography A, Volume 1550 Author(s): Szymon Dziomba, Krzesimir Ciura, Paulina Kocialkowska, Adam Prahl, Bartosz Wielgomas Capillary zone electrophoresis (CZE) of unmodified …

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550

Author(s): Szymon Dziomba, Krzesimir Ciura, Paulina Kocialkowska, Adam Prahl, Bartosz Wielgomas

Capillary zone electrophoresis (CZE) of unmodified gold nanoparticles (Au NPs) was investigated in terms of dispersion stability in a presence of buffering counter-ions in background electrolyte (BGE). Capillary length, migration time and electric field strength were identified among factors influencing particles CZE. Moreover, BGE electrolysis was found to significantly affect analyses repeatability. The adsorption of NPs to capillary wall was recognized as the main problem. It was shown that this inconvenience can be overcome by the application of relatively big counter-ions. According to this observation, steric stabilization of NPs suspension by BGE components during CZE was hypothesized. In result, repeatable CZE of bare Au NPs under dynamic coating conditions was shown.





Flow variation as a factor determining repeatability of the internal standard-based qualitative and quantitative analyses by capillary electrophoresis

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548
Author(s): Paweł Mateusz Nowak, Michał Woźniakiewicz, Paweł Kościelniak
The use of migration times and peak areas referred to another sample component − internal standard, brings many benefits in improving reliability of capillary electrophoresis. However, it is quite commonly overlooked that despite relative migration time and peak area ratio are more stable than the absolute values upon alteration in the flow rate, some shift should always be expected. The present work offers a new look at this analytically-important issue. We have derived a simple model allowing to estimate the magnitude of error for the selected pair of molecules of known mobilities upon the given flow alteration. Then, we have confronted the theoretical predictions with the experimental results obtained for the model sample separated in various flow conditions reached by the external pressure manipulation, including several internal standards of different mobilities. A good agreement has been obtained, pointing out that the magnitude of error may be large even for the seemingly “good” internal standards. Several potentially useful means have been tested to address this issue: the use of electrophoretic mobilities and electrophoretic mobility ratios instead migration times in the qualitative analysis, and performing time-correction of peak area ratios, or alternatively, transformation of electropherograms from the time-related scale into the electrophoretic mobility-related scale in the quantitative analysis. We have also considered some additional factors. The results may be of interest for all users dealing with the development and optimization of analytical methods using capillary electrophoresis.

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548

Author(s): Paweł Mateusz Nowak, Michał Woźniakiewicz, Paweł Kościelniak

The use of migration times and peak areas referred to another sample component − internal standard, brings many benefits in improving reliability of capillary electrophoresis. However, it is quite commonly overlooked that despite relative migration time and peak area ratio are more stable than the absolute values upon alteration in the flow rate, some shift should always be expected. The present work offers a new look at this analytically-important issue. We have derived a simple model allowing to estimate the magnitude of error for the selected pair of molecules of known mobilities upon the given flow alteration. Then, we have confronted the theoretical predictions with the experimental results obtained for the model sample separated in various flow conditions reached by the external pressure manipulation, including several internal standards of different mobilities. A good agreement has been obtained, pointing out that the magnitude of error may be large even for the seemingly “good” internal standards. Several potentially useful means have been tested to address this issue: the use of electrophoretic mobilities and electrophoretic mobility ratios instead migration times in the qualitative analysis, and performing time-correction of peak area ratios, or alternatively, transformation of electropherograms from the time-related scale into the electrophoretic mobility-related scale in the quantitative analysis. We have also considered some additional factors. The results may be of interest for all users dealing with the development and optimization of analytical methods using capillary electrophoresis.





A screening method for cardiovascular active compounds in marine algae

Publication date: 18 May 2018 Source:Journal of Chromatography A, Volume 1550 Author(s): S. Agatonovic-Kustrin, E. Kustrin, M.J. Angove, D.W. Morton The interaction of bioactive compounds from ethanolic extracts of selected mar…

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550

Author(s): S. Agatonovic-Kustrin, E. Kustrin, M.J. Angove, D.W. Morton

The interaction of bioactive compounds from ethanolic extracts of selected marine algae samples, separated on chromatographic plates, with nitric/nitrous acid was investigated. The nature of bioactive compounds in the marine algae extracts was characterised using UV absorption spectra before and after reaction with diluted nitric acid, and from the characteristic colour reaction after derivatization with anisaldehyde. It was found that diterpenes from Dictyota dichotoma, an edible brown algae, and sterols from green algae Caulerpa brachypus, bind nitric oxide and may act as a nitric oxide carrier. Although the carotenoid fucoxanthin, found in all brown marine algae also binds nitric oxide, the bonds between nitrogen and the fucoxanthin molecule are much stronger. Further studies are required to evaluate the effects of diterpenes from Dictyota dichotoma and sterols from green algae Caulerpa brachypus to see if they have beneficial cardiovascular effects. The method reported here should prove useful in screening large numbers of algae species for compounds with cardiovascular activity.





Liquid chromatography – high resolution mass spectrometry method for monitoring of 17 mycotoxins in human plasma for exposure studies

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548
Author(s): Irina Slobodchikova, Dajana Vuckovic
Mycotoxins are secondary metabolites produced by filamentous fungi. Primary route of human exposure to mycotoxins is the intake of the contaminated food. Minimizing mycotoxin exposure is important for population health, as their chronic toxic effects have been associated with kidney and liver diseases, some types of cancer and immunosuppression. The objective of this work was to develop and validate a multi-class mycotoxin method suitable for exposure monitoring of mycotoxins in human plasma. A sensitive liquid chromatography – mass spectrometry method was developed for 17 mycotoxins: nivalenol (NIV), deoxynivalenol, fusarenon X, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, T-2 toxin, HT-2 toxin, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, zearalenone, α-zearalenol (α-ZOL), β-zearalenol, zearalanone, α-zeranol and, and β-zeranol. The method relies on three-step liquid–liquid extraction with ethyl acetate to eliminate the need for immunoaffinity extraction and minimize ionization matrix effects. Chromatographic separation of mycotoxins, including all isomers, was achieved with pentafluorophenyl column and water/methanol mobile phase. Mycotoxin detection and quantitation were performed using high-resolution mass spectrometry on LTQ Velos Orbitrap, in both positive and negative electrospray ionization (ESI(+) and (ESI(−)). The use of 0.02% acetic acid as mobile phase additive for ESI(−) resulted in significant increase in ionization efficiency ranging from 1.7 to 26 times for mycotoxins that ionize better in ESI(−). The optimized method was validated according to FDA guidance procedures. LOQs of all mycotoxins ranged from 0.1 to 0.5 ng/ml, except NIV which resulted in LOQ of 3 ng/ml because of low extraction recovery of this highly polar mycotoxin. Mean intra-day accuracy ranged from 85.8% to 116.4%, and intra-day precision (n = 6) ranged from 1.6% to 12.5% RSD for all mycotoxins except α-ZOL where mean accuracy ranged from 72.9% to 97.2%. Inter-day accuracy and precision were 85.6%–111.5% and 2.7–15.6% RSD respectively, showing good analytical performance of the method for biomonitoring.

Publication date: 4 May 2018
Source:Journal of Chromatography A, Volume 1548

Author(s): Irina Slobodchikova, Dajana Vuckovic

Mycotoxins are secondary metabolites produced by filamentous fungi. Primary route of human exposure to mycotoxins is the intake of the contaminated food. Minimizing mycotoxin exposure is important for population health, as their chronic toxic effects have been associated with kidney and liver diseases, some types of cancer and immunosuppression. The objective of this work was to develop and validate a multi-class mycotoxin method suitable for exposure monitoring of mycotoxins in human plasma. A sensitive liquid chromatography – mass spectrometry method was developed for 17 mycotoxins: nivalenol (NIV), deoxynivalenol, fusarenon X, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, T-2 toxin, HT-2 toxin, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, zearalenone, α-zearalenol (α-ZOL), β-zearalenol, zearalanone, α-zeranol and, and β-zeranol. The method relies on three-step liquid–liquid extraction with ethyl acetate to eliminate the need for immunoaffinity extraction and minimize ionization matrix effects. Chromatographic separation of mycotoxins, including all isomers, was achieved with pentafluorophenyl column and water/methanol mobile phase. Mycotoxin detection and quantitation were performed using high-resolution mass spectrometry on LTQ Velos Orbitrap, in both positive and negative electrospray ionization (ESI(+) and (ESI(−)). The use of 0.02% acetic acid as mobile phase additive for ESI(−) resulted in significant increase in ionization efficiency ranging from 1.7 to 26 times for mycotoxins that ionize better in ESI(−). The optimized method was validated according to FDA guidance procedures. LOQs of all mycotoxins ranged from 0.1 to 0.5 ng/ml, except NIV which resulted in LOQ of 3 ng/ml because of low extraction recovery of this highly polar mycotoxin. Mean intra-day accuracy ranged from 85.8% to 116.4%, and intra-day precision (n = 6) ranged from 1.6% to 12.5% RSD for all mycotoxins except α-ZOL where mean accuracy ranged from 72.9% to 97.2%. Inter-day accuracy and precision were 85.6%–111.5% and 2.7–15.6% RSD respectively, showing good analytical performance of the method for biomonitoring.





Graphene-coated polystyrene-divinylbenzene dispersive solid-phase extraction coupled with supercritical fluid chromatography for the rapid determination of 10 allergenic disperse dyes in industrial wastewater samples

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550
Author(s): Chaoyan Lou, Can Wu, Kai Zhang, Dandan Guo, Lei Jiang, Yang Lu, Yan Zhu
Allergenic disperse dyes are a group of environmental contaminants, which are toxic and mutagenic to human beings. In this work, a method of dispersive solid-phase extraction (d-SPE) using graphene-coated polystyrene-divinylbenzene (G@PS-DVB) microspheres coupled with supercritical fluid chromatography (SFC) was proposed for the rapid determination of 10 allergenic disperse dyes in industrial wastewater samples. G@PS-DVB microspheres were synthesized by coating graphene (G) sheets onto polystyrene-divinylbenzene (PS-DVB) polymers. Such novel sorbents were employed in d-SPE for the purification and concentration of allergenic disperse dyes in wastewater samples prior to the determination by SFC with UV detection. To achieve the maximum extraction efficiency for the target dyes, several parameters influencing d-SPE process such as sorbent dosage, extraction time, desorption conditions were investigated. SFC conditions including stationary phase, modifier composition and percentage, column temperature, backpressure and flow rate were optimized to well separate the allergenic disperse dyes. Under the optimum conditions, satisfactory linear relationship (R ≥ 0.9989) was observed with the concentration of dyes ranging from 0.02 to 10.0 μg/mL. The limits of detection (LOD, S/N = 3) for the ten dyes were in the range of 1.1–15.6 ng/mL. Recoveries for the spiked samples were between 89.1% and 99.7% with relative standard deviations (RSD) lower than 10.5% in all cases. The proposed method is time-saving, green, precise and repeatable for the analysis of the target dyes. Furthermore, the application of G@PS-DVB based d-SPE process can be potentially expanded to isolate and concentrate other aromatic compounds in various matrices and supercritical fluid chromatography methodology featuring rapidity, accuracy and green will be an ideal candidate for the analysis of these compounds.

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550

Author(s): Chaoyan Lou, Can Wu, Kai Zhang, Dandan Guo, Lei Jiang, Yang Lu, Yan Zhu

Allergenic disperse dyes are a group of environmental contaminants, which are toxic and mutagenic to human beings. In this work, a method of dispersive solid-phase extraction (d-SPE) using graphene-coated polystyrene-divinylbenzene (G@PS-DVB) microspheres coupled with supercritical fluid chromatography (SFC) was proposed for the rapid determination of 10 allergenic disperse dyes in industrial wastewater samples. G@PS-DVB microspheres were synthesized by coating graphene (G) sheets onto polystyrene-divinylbenzene (PS-DVB) polymers. Such novel sorbents were employed in d-SPE for the purification and concentration of allergenic disperse dyes in wastewater samples prior to the determination by SFC with UV detection. To achieve the maximum extraction efficiency for the target dyes, several parameters influencing d-SPE process such as sorbent dosage, extraction time, desorption conditions were investigated. SFC conditions including stationary phase, modifier composition and percentage, column temperature, backpressure and flow rate were optimized to well separate the allergenic disperse dyes. Under the optimum conditions, satisfactory linear relationship (R ≥ 0.9989) was observed with the concentration of dyes ranging from 0.02 to 10.0 μg/mL. The limits of detection (LOD, S/N = 3) for the ten dyes were in the range of 1.1–15.6 ng/mL. Recoveries for the spiked samples were between 89.1% and 99.7% with relative standard deviations (RSD) lower than 10.5% in all cases. The proposed method is time-saving, green, precise and repeatable for the analysis of the target dyes. Furthermore, the application of G@PS-DVB based d-SPE process can be potentially expanded to isolate and concentrate other aromatic compounds in various matrices and supercritical fluid chromatography methodology featuring rapidity, accuracy and green will be an ideal candidate for the analysis of these compounds.





Integrated strategy for identifying minor components in complex samples combining mass defect, diagnostic ions and neutral loss information based on ultra-performance liquid chromatography-high resolution mass spectrometry platform: Folium Artemisiae Argyi as a case study

Publication date: 18 May 2018 Source:Journal of Chromatography A, Volume 1550 Author(s): Dabing Ren, Lu Ran, Chong Yang, Meilin Xu, Lunzhao Yi Ultra-performance liquid chromatography coupled to high-resolution mass spectromet…

Publication date: 18 May 2018
Source:Journal of Chromatography A, Volume 1550

Author(s): Dabing Ren, Lu Ran, Chong Yang, Meilin Xu, Lunzhao Yi

Ultra-performance liquid chromatography coupled to high-resolution mass spectrometry (UPLC-HRMS) has been used as a powerful tool to profile chemicals in traditional Chinese medicines. However, identification of potentially bioactive compounds is still a challenging work because of the large amount of information contained in the raw UPLC-HRMS data. Especially the ubiquitous matrix interference makes it more difficult to characterize the minor components. Therefore, rapid recognition and efficient extraction of the corresponding parent ions is critically important for identifying the attractive compounds in complex samples. Herein, we propose an integrated filtering strategy to remove un-related or interference MS1 ions from the raw UPLC-HRMS data, which helps to retain the MS features of the target components and expose the compounds of interest as effective as possible. The proposed strategy is based on the use of a combination of different filtering methods, including nitrogen rule, mass defect, and neutral loss/diagnostic fragment ions filtering. The strategy was validated by rapid screening and identification of 16 methoxylated flavonoids and 55 chlorogenic acids analogues from the raw UPLC-HRMS dataset of Folium Artemisiae Argyi. Particularly, successful detection of several minor components indicated that the integrated strategy has obvious advantages over individual filtering methods, and it can be used as a promising method for screening and identifying compounds from complex samples, such as herbal medicines.