Being restrained by the limited peak capacity, one‐dimensional chromatography usually leads to an unsatisfactory separation with low purity of compounds in a complex mixture. To obtain more highly ...pure targets for standard reference and to discover new substances for structural elucidation, two‐dimensional chromatography is more and more prevalent in many fields. As few metrics on assessment of the preparative capability of two‐dimensional chromatographic separations are reported, a methodology of in silico screening of various two‐dimensional chromatographic separations with a minimal number of experiments was demonstrated in this work, which was based on three descriptors including the occupation rate of peaks and system homogeneity of a two‐dimensional separation space, and the minimal distance of all nearest‐neighbor distances of peaks. Combining the advantages of counter‐current chromatography and liquid chromatography, we elaborated the methodology by employing off‐line comprehensive two‐dimensional counter‐current chromatography with liquid chromatography to be in silico screened for separation of four saponins from Panax notoginseng at an analytical scale to simulate the case of preparative scale transfer. The predictive results were presented by two‐dimensional contour plots and verified by experiments. The result showed that the experimental results were in general accord with the predictive results.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this paper, the development and application of a multiple heart‐cutting achiral–chiral LC–LC method (mLC–LC) for the analysis of dansylated (Dns) branched‐chain amino acids in commercial tablets ...are described. In the first dimension, a Waters Xbridge RP C18 achiral column was used under gradient conditions with buffered aqueous solution and acetonitrile. The elution order Dns‐valine (Dns‐Val) < Dns‐isoleucine (Dns‐Ile) < Dns‐leucine (Dns‐Leu) turned out with full resolution between adjacent peaks: 7.25 and 1.50 for the Val/Ile and the Ile/Leu pairs, respectively. A “research” validation study was performed, revealing high accuracy (Recovery%) and precision (RSD%) using two external set solutions, respectively, in the range 93.7%–104.1% and 0.4%–3.2%. The C18 column was connected via a two‐position six‐port switching valve to the quinidine‐based Chiralpak quinidine‐anion‐exchange chiral column. A water/acetonitrile, 30/70 (v/v) with 50 mM ammonium acetate (apparent pH of 5.5) eluent allowed getting the three enantiomers’ pairs resolved: RS equal to 4.3 for Dns‐Val and Dns‐Ile, and 1.7 for Dns‐Leu. The application of the mLC‐LC method confirmed that the content of Val, Ile, and Leu in the tablets was compliant with that labeled by the producer. Only l‐enantiomers were found in the food supplement, as confirmed by LC–MS/MS analysis.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Comprehensive two‐dimensional gas chromatography with vacuum ultraviolet detection results in sizable data for which noise and baseline drift ought to be corrected. As the data is acquired from ...multiple channels, preprocessing steps have to be applied to the data from all channels while being robust and rather fast with respect to the significant size of the data. In this study, we have described advanced data preprocessing techniques for such data which were not available in the existing commercial software solutions and which were dedicated primarily to noise and baseline correction. Noise reduction was performed on both the spectral and the time dimension. For the baseline correction, a morphological approach based on iterated convolutions and rectifier operations was proposed. On the spectral dimension, much less noisy and reliable spectra were obtained. From a quantitative point of view, mentioned preprocessing steps significantly improved the signal‐to‐noise ratio for the analyte detection (circa six times in this study). These preprocessing methods were integrated into the plugim! platform (https://www.plugim.fr/).
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A comprehensive two-dimensional (2D) countercurrent chromatography (CCC) × gas chromatography (GC) was investigated for characterization of chemical constituents of Artemisia argyi essential oil, and ...orthogonality for the 2D chromatographic system was evaluated. A solvent system composed of n-hexane/acetonitrile/methanol (2:2:1, v/v/v) was selected for first dimensional separation of Artemisia argyi essential oil. Then all CCC fractions were analyzed by GC, which provided a wealth of information regarding the composition of the essential oil. Visualization of chemical compositions obtained from the comprehensive 2D CCC × GC separation was achieved by creation of a 2D contour plot map. Total peak capacity was evaluated and approximately 1392 peaks were obtained through a comprehensive 2D CCC × GC separation. A high spatial coverage and a low linear correlation coefficient were achieved. Meanwhile, all compounds were identified by GC-MS. The obtained 2D contour plot could be divided into six zones to show the characteristic chemical compositions. Six zones could be divided into different component groups, including monoterpenes, sesquiterpenes, monoterpene alcohols, phenols, aldehydes, ketones and esters, which could be used to identify compounds that have not been reported, and to predict the structure of unknown compounds in Artemisia argyi essential oil and comprehensively characterize fingerprint peak.
Display omitted
•Comprehensive 2D CCC × GC chromatographic analysis of Artemisia argyi essential oil.•Orthogonality metric was evaluated by convex hull and linear correlation coefficient.•Development of a 2D contour map for a complete and informative assessment of sample.•Separation and characterization of new constituents in Artemisia argyi essential oil.•Zonal substance classification for comprehensive identification of fingerprint peaks.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Comprehensive two-dimensional chromatography generates complex data sets, and numerous baseline correction and noise removal algorithms have been proposed in the past decade to address this ...challenge. However, evaluating their performance objectively is currently not possible due to a lack of objective data.
To tackle this issue, we introduce a versatile platform that models and reconstructs single-trace two-dimensional chromatography data, preserving peak parameters. This approach balances real experimental data with synthetic data for precise comparisons. We achieve this by employing a Skewed Lorentz-Normal model to represent each peak and creating probability distributions for relevant parameter sampling. The model's performance has been showcased through its application to two-dimensional gas chromatography data where it has created a data set with 458 peaks with an RMSE of 0.0048 or lower and minimal residuals compared to the original data. Additionally, the same process has been shown in liquid chromatography data.
Data analysis is an integral component of any analytical method. The development of new data processing strategies is of paramount importance to tackle the complex signals generated by state-of-the-art separation technology. Through the use of probability distributions, quantitative assessment of algorithm performance of new algorithms is now possible. Therefore, creating new opportunities for faster, more accurate, and simpler data analysis development.
Display omitted
•Benchmark data is needed for objective evaluation of data-processing algorithms.•A Skewed Lorenz-Normal distribution is applied to describe chromatographic peaks.•A tool was developed to generate highly realistic chromatographic data.•The simulation of realistic data is demonstrated on LC × LC and GC × GC signals.•This tool may facilitate further the development of data analysis workflows.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The analysis of complex samples is facilitated by the emergence of two-dimensional liquid chromatography. Despite optimization efforts to reach tremendous peak capacities, the separation of neutral ...compounds remains limited. Indeed, most combinations of chromatographic modes suffer either from a lack of orthogonality or from serious solvent incompatibilities. The two-dimensional separation involving a combination of liquid chromatography and supercritical fluid chromatography seems to offer new opportunities for the separation of ionizable and neutral solutes. This review highlights the orthogonality the combination can offer thanks to a wide range of stationary phases. Injection effects occurring in SFC, that may drastically reduce the performances of online LC × SFC are also discussed in details. Finally, despite net improvement in SFC instrumentation in the recent years, instrumental limitations still have to be overcome. While this review highlights the potential of LC and SFC combination and its complementarity with 2D-LC, it also demonstrates that its development requires the joint efforts of researchers and instrumental suppliers before comprehensive LC × SFC gets adopted by the scientific community.
•The separation of neutral molecules is limited in LC × LC.•Two-dimensional LC × SFC or SFC × LC combinations exhibit interesting orthogonality for the separation of neutral molecules.•Injection effects in SFC are still under investigation.•Specific interfaces have been proposed but a commercial instrumentation is still lacking.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We applied an extended charge‐based fractional diagonal chromatography (ChaFRADIC) workflow to analyze the N‐terminal proteome of Arabidopsis thaliana seedlings. Using iTRAQ protein labeling and a ...multi‐enzyme digestion approach including trypsin, GluC, and subtilisin, a total of 200 μg per enzyme, and measuring only one third of each ChaFRADIC‐enriched fraction by LC‐MS, we quantified a total of 2791 unique N‐terminal peptides corresponding to 2249 different unique N‐termini from 1270 Arabidopsis proteins. Our data indicate the power, reproducibility, and sensitivity of the applied strategy that might be applicable to quantify proteolytic events from as little as 20 μg of protein per condition across up to eight different samples. Furthermore, our data clearly reflect the methionine excision dogma as well as the N‐end rule degradation pathway (NERP) discriminating into a stabilizing or destabilizing function of N‐terminal amino acid residues. We found bona fide NERP destabilizing residues underrepresented, and the list of neo N‐termini from wild type samples may represent a helpful resource during the evaluation of NERP substrate candidates. All MS data have been deposited in the ProteomeXchange with identifier PXD001855 (http://proteomecentral.proteomexchange.org/dataset/PXD001855).
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The occurrence of mineral oil in food is known since the early 1990s, and it was discovered by chance in one of the first applications using the hyphenated LC–GC system. Since then, the relationship ...between hyphenated techniques and mineral oil analysis has been tightly interrelated and successful. This review aims to show and explain how this mutual interaction has driven the development of the hyphenated techniques on one side and has supported the increase of knowledge on the other, supporting the complex task of mineral oil determination in food. The paper presents the background of the mineral oil problem in food (a brief history of its finding, toxicology, and occurrence), moving then toward the analytical determination. The development of different hyphenated techniques in relation to mineral oil determination is discussed, focusing mainly on 2D techniques, such as LC–GC. The necessity of additional dimensions, such as LC–LC–GC and comprehensive approaches, such as GC × GC and LC × GC, is also discussed. Finally, the role of the hyphenation with MS is presented.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Off‐line comprehensive two‐dimensional reversed‐phase countercurrent chromatography with high‐performance liquid chromatography was investigated in separation of crude ethanol extract from ...traditional Chinese medicinal herb Polygonum cuspidatum Sieb. et Zucc. Two‐dimensional contour plots for countercurrent chromatography with high‐performance liquid chromatography was obtained after comprehensive separation was completed. Total peak capacity was evaluated and approximately 810 peaks were obtained through a comprehensive two‐dimensional separation. A highly orthogonality of 52.23% and a large separation space occupancy of 88.86% were achieved. Meanwhile, it was found that several components could be well separated by countercurrent chromatography while they could not be separated by high‐performance liquid chromatography, and vice versa, which further indicated the orthogonality of the two separation methods. The off‐line comprehensive two‐dimensional countercurrent chromatography with high‐performance liquid chromatography provided a promising and powerful method for separation of complex natural products.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Comprehensive two-dimensional liquid chromatography platform (LC×LC) coupled with quadrupole time-of-flight (QTOF) mass spectrometry (MS) is developed to separate, identify and relatively determine ...the chemical constituents of two types of tripterygium glycosides tablets (TGT). The types and relative contents of the constituents discovered in two kinds of TGT tablets were subsequently compared. C8 and C18 column were used for the separation of the first and second dimensional chromatography (1D and 2D) respectively, and an integrated shift and full gradient mode was used in 2D. Using this LC×LC–QTOF-MS platform, 92 and 132 constituents were detected in TGT preparations from Hubei and Hunan manufacturers respectively (HB-TGT and HN-TGT), most of which belonged to the diterpenoid, triterpenoid and alkaloid families. 50 and 90 compounds were unique in HB-TGT and HN-TGT, respectively, and their relative contents proportion were 52.0% and 54.2% of HB-TGT and HN-TGT, respectively. Furthermore, two TGT tablets could both lead to obvious change in biochemical parameters, oxidative stress related parameters and histopathological status to different degree. In all, the LC×LC–QTOF-MS platform offer a powerful and efficient method for characterizing, identifying and semi-quantifying chemical components in TGT preparations.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
PDF
