查看更多>>摘要：N-Rich is a twin-column chromatography process that enriches target compounds relative to other components in a mixture, thereby facilitating their isolation and characterization. This study demonstrates the performance of N-Rich for isolation of Angiotensin II peptide impurities compared with standard analytical and preparative chromatography approaches. Peptides have diverse chemical properties and are produced using a wide range of methods, resulting in products with complex impurity profiles. The characterization of impurities for clinical development is essential but obtaining high purity samples in sufficient quantities is often a difficult task when using standard chromatographic techniques. In contrast, by using cyclic continuous chromatography with UV-based process control, N-Rich enables automatic on column accumulation of target impurities while other compounds in the mixture are depleted. This has multiple advantages compared to standard techniques. Firstly, at the end of the cyclic accumulation phase the highly enriched target is eluted in one step with high purity and concentration. This means fewer fractions for analysis are generated and up-concentration steps are reduced. Secondly, the purification of target impurities using semi-preparative scale chromatography becomes viable, even if initial resolution is poor compared to analytical HPLC. This allows for very significant increases in productivity for purification of difficult to isolate impurities. This study demonstrates two N-Rich strategies: Example 1: Purification of mu g quantities of multiple Angiotensin II impurities with a > 9-fold increase in productivity compared to analytical HPLC. Example 2: Specific isolation of 1 mg of a critical impurity at 88% purity. 79-fold increase in productivity and a 69-fold reduction in solvent consumption compared to analytical HPLC. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
查看更多>>摘要：In this paper, in order to solve signal instability of high-performance liquid chromatography-diode array detection (HPLC-DAD) data and maintain the second-order advantage, this work proposed piecewise direct standardization (PDS) assisted with second-order calibration methods to analyze two different complex HPLC-DAD data with signal instability, including simulated HPLC-DAD data and the data of pesticide residues in saffron. Accurate quantitative results of target analytes can be obtained by PDS combined with alternating trilinear decomposition algorithm (ATLD) and alternating trilinear decomposition assisted multivariate curve resolution algorithm (ATLD-MCR) in the presence of signal instability with time shifts and changes of peak shape. Quantitative results of the model after calibration transfer are better than those of the model established by calibration sets and prediction sets with signal instability using ATLD algorithm and ATLD-MCR algorithm under different situations. Meanwhile, t-test was used to judge whether there are significant differences between these quantitative results of models. The performances of MCR-ALS algorithm were compared with that of PDS-ATLD method and PDS-ATLD-MCR method and the proposed methods have greater potential in dealing with the case of signal instability with time shifts and changes of peak shape. In a word, this methodology can reduce the number of calibration samples for recalibration and modeling, improve the efficiency of experiment, conform to the principle of green chemistry, and obtain satisfactory quantitative results in the presence of signal instability with time shifts and changes of peak shape. (c) 2022 Elsevier B.V. All rights reserved.
Gerstweiler, LukasBillakanti, JaganBi, JingxiuMiddelberg, Anton P. J....
8页
查看更多>>摘要：Fluctuations of the inlet feed stream concentration are a challenge in controlling continuous multi column counter current chromatography systems with standard methods. We propose a new control strategy based on calculated product column breakthrough from UV sensor signals by neglecting an impurity baseline and instead using the impurity to product ratio. This calculation is independent of the inlet feed concentration. In-silico simulation showed that the proposed method can calculate the product column breakthrough perfectly even with fluctuating and highly unstable inlet feed concentration during a loading cycle. Applying the proposed method to control a three column periodic counter current chromatography process with fluctuating inlet feed concentration resulted in constant column loading in each cycle, while using the standard method failed to do so. Unavoidable band broadening caused by diffusion and dispersion has been identified as an inherent limiting factor for accurate calculation of column breakthrough comparing inlet and outlet UV signals. The proposed advanced calculations increase the robustness of periodic counter current chromatography and extend the capability to process unstable inlet streams. (c) 2022 Elsevier B.V. All rights reserved.
Schoneich, SoniaOchoa, Grant S.Monzon, Celina M.Synovec, Robert E....
14页
查看更多>>摘要：Integration of rice and fish farming, e.g., pacu fish in Argentina, has raised concern that herbicides used for rice paddies may adversely affect the fish metabolome. To study this issue, tile-based Fisher ratio (F-ratio) analysis was applied to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC xGC-TOFMS) data of pacu fish raised in an integrated rice-fish farming system (farmed class) versus fish raised in tanks (tank-raised class) to discover class-distinguishing analytes. Fratio analysis resulted in hit lists initially dominated by artifact peaks from the sample derivatization process, as well as some redundant hits. These challenges were addressed by developing an automated artifact removal algorithm and an improvement to redundant hit removal in the tile-based F-ratio analysis using a pooled farmed fish sample, either spiked with 29 metabolites (spiked class) or unspiked (i.e., the background serving as the control class). Of the 29 spiked metabolites, 23 were discovered by standard F-ratio analysis, improving to 28 discovered using control-normalized F-ratio analysis. Standard and control-normalized F-ratio hit lists initially with 185 and 246 hits, were reduced to 56 and 49 hits, respectively, after artifact removal and removing redundant hits. Next, we returned to the F-ratio analysis of the farmed fish versus the control fish. Here, we introduce a minimum variance optimized (MVO) F-ratio calculation ( MVO F-ratio) that provides a comprehensive hit list ranking. The initial MVO F-ratio analysis hit list of 537 hits was reduced to 110 hits following artifact removal. Of the 110 hits, 70 expressed a concentration ratio statistically different than 1 ( p < 0.05). The MVO F-ratio hit list discovered more true positives compared to the standard, tank-normalized, and farm-normalized F-ratio hit lists, providing the combination of results from the farm-normalized and tank-normalized hit lists. A majority of analytes (54 out of 70) important for normal biological functioning of pacu fish were significantly downregulated in the farmed fish, suggesting the integrated farming system may negatively impact pacu fish quality. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Ultrafast gas chromatography (UFGC) using a moderately polar column was compared to traditional gas chromatography (GC) for evaluation of biodiesel-diesel blended fuels. Several biodiesel feedstocks (soybean, tallow, canola, palm, camelina) and concentrations (1-20%) were evaluated, with specific attention to the separation of fatty acid methyl esters (FAMEs) from the biodiesel component. UFGC is compared to traditional GC using a similar column chemistry. Principal component analysis (PCA) is performed to identify clustering based on feedstock and concentration. UFGC proves an effective and fast technique, comparable to traditional GC, for the analysis of biodiesel-diesel blended fuels. (c) 2022 Elsevier B.V. All rights reserved.
Abbasi, Nabeel MujtabaFarooq, Muhammad QamarAnderson, Jared L.
11页
查看更多>>摘要：Choline chloride-based deep eutectic solvents (DESs) are immensely popular in organic synthesis, catalysis, electrochemistry, and separation science. A popular choice of hydrogen bond donor (HBD) among these DESs consists of both straight-chain and branched polyols that can incorporate additional functional groups, such as ether linkages. Previous studies have shown that the extraction efficiency is significantly altered when the molar ratio of HBD in choline chloride-based DES systems is varied, but no study has been able to relate it to their solvation characteristics. This is largely due to the limited sensitivity of existing solvatochromic dye techniques to detect minor changes in solvation interactions when the DES composition is varied. In this study, inverse gas chromatography was employed for the first time to investigate the variation in solvation properties for DESs comprised of choline salts as hydrogen bond acceptors (HBAs) and polyols as HBDs when their HBA/HBD ratio is systematically altered. Unlike many organic solvents, DES systems investigated in this work possessed a significant hydrogen bond character. It was observed that the hydrogen bond basicity generally plateaued at higher molar ratios of HBD while the hydrogen bond acidity was observed to be the highest at HBA/HBD ratios of 1:10 in all DESs. Amongst all solvents, neat HBDs (triethylene glycol and 1,8-octane diol) possessed the weakest hydrogen bond basicity since they lack the chloride anion that acts as the primary hydrogen bond acceptor. Results from this study demonstrate that the solvation characteristics of DESs are largely different from their starting materials while the HBA/HBD ratio further influences their solvation interactions that can in turn impact important parameters such as extraction yields. (c) 2022 Elsevier B.V. All rights reserved.
von Muhlen, CarinMangelli, Luciana N. R.Marriott, Philip J.
10页
查看更多>>摘要：The definition of a chromatographic analysis speed based simply on analysis time is an outdated concept to define conventional chromatography, fast chromatography, and emerging high-resolution techniques such as comprehensive two-dimensional and comprehensive three-dimensional gas chromatography. Here, the metric average theoretical peak time (ATPT) is proposed for separation speed, considering conventional and multidimensional separations. ATPT can be defined as the time (in ms per peak) needed to elute a theoretical peak in a chromatographic system. Using this metric, it is possible to define ranges, proposed for a normal speed (ATPT higher than 40 0 0 ms/peak), high speed (ATPT range from 600 to 40 0 0 ms/peak), very high speed (ATPT range from 200 to 600 ms/peak), hyper speed (ATPT range from 3.3 to 200 ms/peak) and ultra high speed chromatography (ATPT lower than 3.3 ms/peak), that combines time and efficiency metrics. This metric was applied in several contexts to demonstrate its robustness to evaluate chromatographic separations for different techniques and analytical conditions. Applications also demonstrate the advantages of the use of ATPT as a method development metric tool. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Two new hydrophilic-hydrophobic and acid-base balanced liquid chromatographic stationary phases were obtained by using two long-chain monomers including undecylenic acid (UA) and oleic acid (OA) combined with short-chain 4-vinyl pyridine (Py) in-situ polymerized on silica microspheres surfaces, respectively. These two stationary phases can be used for reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) modes. Hydrophilic, hydrophobic, acidic and basic analytes can be separated on two new stationary phases in RPLC or HILIC mode. Compared with commercial hydrophobic C18 columns and other HILIC columns, two new stationary phases have excellent selectivity and separation performance in the separation of 9 polycyclic aromatic hydrocarbons, 10 aromatic acids, 10 anilines and 5 oxazolidinones, respectively. This novel polymer-functionalized silica design strategy has opened up new ideas for the future of mixed-mode stationary phases with multiple functions and specificity. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：We describe and discuss a simple dry-compression technique for preparing a flat cuboid chromatography device containing a shallow packed-bed of crystalline hydroxyapatite nanoparticles. We then discuss the use of this device for fast protein separation in the bind-and-elute mode. Such separation could be carried out at quite low pressures, making it possible to use inexpensive low pressure chromatography systems. In the flow rate range examined in this study, the pressure-drop across the device increased linearly with flow rate, indicating negligible media compaction during use. Using this device, binary protein mixtures could be separated in about a minute. Contrary to that observed in most packed-bed chromatographic separations, the width of the flow through and eluted peaks decreased with increase in flow rate. Therefore, both productivity and purity could be simultaneously increased by increasing flow rate. The suitability of this device for preparative protein separations was demonstrated by carrying out purification of a monoclonal antibody (Trastuzumab) from mammalian cell culture supernatant. This study opens up the possibility of developing dry-compression based flat cuboid packed-bed chromatography devices for fast preparative protein separation. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The development of combination vaccines is essential to reduce the number of injections, shorten vaccination schedules and increase vaccination coverage. Vaccine adjuvants are used to modulate and enhance the immune response induced by the antigens. To support the development of combination vaccines, the study of antigen-adjuvant interactions in the final vaccine formulations is required as interaction competitions may take place between the different antigens. In the present work, a capillary zone electrophoresis (CZE) methodology was firstly optimized on six model proteins, namely bovine serum albumin, beta-lactoglobulin, myoglobin, ribonuclease A, cytochrome C and lysozyme. A cationic dynamic coating (polybrene) and a zwitterionic amino acid additive ( beta-alanine) in the background electrolyte were used to reduce the phenomena of protein adsorption on the inner wall of the capillary and thus optimize the separation efficiency of the proteins. The developed methodology was then used to separate three strains from inactivated polio virus, each strain being a whole virus composed of copies of 4 viral proteins and study their interaction with aluminum oxyhydroxide. The antigen-adjuvant interactions could be modulated by addition of phosphate ions playing the role of competitors for the poliovirus. (c) 2022 Elsevier B.V. All rights reserved.
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