Kong, LiyunWang, JiaqiGao, QingpengLi, Xiaoqian...
9页查看更多>>摘要：The determination of fat-soluble vitamins and carotenoids in human serum provides reliable information for diagnosing malnutrition and for establishing appropriate intervention programs. Due to the complex composition of the biological samples, the efficient sample preparation is the key to the analysis. We report here a surface active ionic liquid (SAIL)-based dispersive liquid-liquid microextraction (DLLME) method coupled with a high performance liquid chromatography (HPLC) to determine four fat-soluble vitamins and six carotenoids in human serum simultaneously. Liquid crystal structures were formed in the extract phase. And the enrichment factor of the analytes treated by DLLME was 4 to 26 times of the traditional LLE method except lycopene. The limit of determination for these compounds was determined to be between 0.002 and 0.076 mu g/mL. The accuracy was validated by the standard addition method with recoveries ranging from 82.4 to 114.1%. The intra-day and inter-day relative standard deviations were 2.76-12.63% and 4.01-13.54%, respectively. The proposed DLLME coupled with the HPLC method was successfully applied in the determination of fat-soluble micronutrients in human serum. (c) 2022 Elsevier B.V. All rights reserved.
原文链接:
NSTL
Elsevier
Wang, YangZhang, XueWei, Ze-HuiJiao, Ya-Jie...
11页查看更多>>摘要：A new dual-function enzyme reactor was prepared based on a dopamine/graphene oxide coated boron affinity monolithic column, which can be used for simultaneous protein enzymatic hydrolysis and glycopeptide enrichment. Firstly, a boron affinity monolithic column was prepared as the carrier for enzyme reactor. Secondly, the monolithic column was coated with dopamine/graphene oxide to provide higher specific surface area for the increase in the amount of trypsin bound. Then, dopamine can self-polymerize under alkaline conditions to produce multiple reaction sites. By the Schiff base reaction and Michael addition reaction with amino, sulffiydryl groups to trypsin, enzyme were immobilized on the boron affinity monolithic carrier. The enzyme activity was characterized by kinetic parameters maximum rate (V-max) of the enzyme reaction and Michaelis constant (K-m). K-m of the dual-function enzyme reactors doped with PDA/GO and without PDA/GO were 34.37 and 120.93 mM, V-max were 1.35 and 3.35 mM/min, respectively. The performance of the dual-function enzyme reactor was evaluated by protein extraction of mouse liver. After digested by the dual-function enzyme reactor, the number of peptides was 4,801, which was 960 more than the number of peptides in the solution digestion. At the same time, the dual-function enzyme reactor displayed the ability to capture cis-dihydroxy compounds specificly. A total of 55 glycopeptides were enriched in the dual-functional enzyme reactor, corresponding to 33 glycoproteins. The dual-function enzyme reactor provided repeatable performance and robust with long-term storage. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Simeone, JenniferPatel, Amit, VDeLano, MathewShiner, Stephen J....
9页查看更多>>摘要：It is critical to the success of any chromatography-based assay that the performance of the LC instrument be checked for its readiness and ability to perform the intended analysis. This includes gaging the suitability of a system to fulfill the purpose of different types of methods. One type of analysis that requires special consideration is the analysis of compounds which are prone to a particular form of non-specific binding, namely metal adsorption, where analytes interact and potentially adsorb to metal contained within the chromatographic flow path. For an analysis of compounds which are susceptible to metal adsorption, ideally a system suitability test would be performed to ensure there will not be any sample loss or detrimental peak shape effects resulting from potential analyte-to-metal interactions. To help chromatographers assess system inertness concerns like this, we have developed a method of testing LC systems for metal interactions using adenosine 5'-(alpha,beta-methylene)diphosphate (AMPcP). This nucleotide analog has been confirmed to have a propensity to adsorb to titanium and stainless-steel fits and is resistant to hydrolysis and stable to long-term storage and repeat use (as is befitting of any reagent proposed for system suitability testing). AMPcP has been used in a flow injection test (no column inline) to monitor for losses in recovery and peak shape perturbations that can potentially be present in any chromatography system manufactured with one or more metal based components. In this approach, sequential injections of AMPcP were made without a column and various peak attributes were monitored and ultimately correlated to the amount of metal surface area in the flow path. The ability of this method to discriminate between inert chromatographic surfaces versus exposed metal surfaces was verified by comparing peak areas, peak shapes, and injection repeatability for AMPcP using a UHPLC equipped with MP35N metal alloy components versus an equivalent UHPLC equipped with an ethylene bridged hybrid organic-inorganic surface (or so-called hybrid surface technology). Injections of caffeine were also explored to establish a negative control for this system suitability measurement. Caffeine does not interact with metal surfaces and can therefore give an instrument specific representation of peak shape and dispersion as well as an indication of overall mechanical system performance. Additionally, replicate injections of AMPcP and caffeine onto a UHPLC partially configured with hybrid surface technology (HST) readily identified exposed metal surfaces through an increased peak area relative standard deviation as well as a reduction in absolute recovery. Finally, a novel visualization tool was developed to provide an alternative method of determining system inertness without having to perform chromatographic calculations but instead a graphical peak shape comparison between a negative control, caffeine, and the metal sensitive AMPcP test probe. (C) 2022 The Author(s). Published by Elsevier B.V.
原文链接:- NSTL
- Elsevier
Wang, Xiu-pingWang, Run-qinPan, Xia-yuXing, Rong-rong...
8页查看更多>>摘要：A switchable deep eutectic solvent-based liquid-phase microextraction was proposed and applied to the preconcentration and determination of liposoluble quality-markers of diterpenoid quinones (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA) in traditional Chinese medicine coupled with high performance liquid chromatography-ultraviolet detection. In the procedure, the hydrophilic deep eutectic solvent of diethanolamine-hexanoic acid (molar ratio 1:1) was prepared and added into the sample phase as an extractant, and a homogeneous solution was formed under slight vortex stirring. After the addition of HCl solution, the deep eutectic solvent miscible with the sample phase was converted to hydrophobic form, and a cloudy solution was generated. Then, the upper hydrophobic layer enriching the target analytes was collected through centrifugation for high performance liquid chromatography analysis. Several critical parameters affecting the extraction performance including the composition and consumption of switchable deep eutectic solvent, the type and amount of acid, salt amount and extraction time were investigated and optimized. Moreover, the structures of the deep eutectic solvent and the recovered hydrophobic layer were both characterized using Fourier transform infrared spectroscopy, further demonstrating the switching mechanism of the extractant during the extraction process. Under the optimal conditions, enrichment factors of diterpenoid quinones ranged from 59 to 274. Good linearities ( r >= 0.9963), low detection limits (0.5-0.7 ng/mL), satisfactory precisions (relative standard deviations 0.5%-8.6%) and accuracies (recoveries 94.6%-104.6%) were also obtained. Comparing the proposed switchable deep eutectic solvent-based liquid-phase microextraction with other published methods, the characteristics of the procedure were summarized. The developed method was successfully applied for the preconcentration of four liposoluble diterpenoid quinones from a traditional Chinese herbal medicine of Salvia Miltiorrhiza.
原文链接:- NSTL
- Elsevier
Schmid, MarcoThi Kieu Tien DoTrettin, IlonaReich, Eike...
10页查看更多>>摘要：The Universal HPTLC Mixture (UHM) consists of eight substances (guanosine, sulisobenzone, thymidine, paracetamol, phthalimide, 9-hydroxyfluorene, thioxanthen-9-one, and 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol) and yields separated zones over the whole RF range for a multitude of developing solvents. Therefore, it could be used in a generic system suitability test (SST) as well as for the verification of quality of HPTLC data. In this work, changes caused by +10% variation of the volume fractions of the developing solvent components were tested on three developing solvents, to investigate the R-F shifts of the UHM zones in comparison to established SSTs and results described for test samples in selected pharmacopeia monographs for identification of herbal drugs. Additionally, one of the developing solvents was investigated with different stationary phases. The components of the UHM showed similar prediction intervals as the substances of established SSTs and specific markers. The UHM could, therefore, be considered for use in an alternative SST. Because it covers the whole R-F range, the UHM can detect changes in developing solvent gradients or saturation effects, whereas many established SSTs generally describe only a limited R-F range. The use of the UHM can help facilitate automation of HPTLC. Furthermore, it can potentially be used for correlating RF shifts across HPTLC plates. The circumstances, under which this is possible, are discussed. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Liu, Ke-XinLi, NingYin, Ying-HaoZhong, Zhu-Jun...
10页查看更多>>摘要：Deep profiling of chemicalome in Chinese medicinal formulas is vital for disclosing the secret underlying their effectiveness. To address this issue, an in-house database-driven untargeted identification strategy was proposed with the use of ultra-performance liquid chromatography coupled to quadrupole time of flight mass spectrometry. Firstly, an in-house mass spectral database for the analyzed herbs was constructed, and database querying was performed for rapid recognition of known compounds. Secondly, a chemical diagnostic characteristics algorithm was originally developed for deep mining unrecorded ions, and thus expanding coverage of components beyond the database. Additionally, we proposed evaluation criteria for the untargeted identification of compounds with different confidence levels. As a case study, the integrated strategy was applied to comprehensively characterize complex multi-type components in Gegen-Qinlian Decoction. A total of 381 compounds were characterized and annotated with four different confidence levels, and 88.40% of these annotated compounds were successfully re-identified in triplicate analyses with a different instrument. The integrated strategy was demonstrated powerful in deep profiling of chemicalome in Chinese medicinal formulas with higher throughput, analytical sharpness, and lower omission ratios. (c) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Xiong, YongqiangChen, HaodongLi, YunJiang, Wenmin...
7页查看更多>>摘要：Compound-specific isotope analysis of crocetane in sediments can be used to determine its origin. However, the co-elution of crocetane with phytane and complex substrates hinders the accurate determination of its isotopic composition. A heart-cutting two-dimensional gas chromatography-isotope ratio mass spectrometry (2D-GC-IRMS) method was developed to determine delta C-13 values of crocetane. Full chromatographic separation of crocetane was achieved with a 30 m CycloSil-B chiral capillary first column and a 60 m Chiraldex B-pH capillary second column (two series-connected 30 m Chiraldex B-pH capillary columns). Analyses of standard mixtures confirmed that the new method has satisfactory accuracy (deviations from the authentic values <0.5 parts per thousand) and precision (RSDs <5%) for carbon isotope analyses of crocetane and phytane. The application of the method to two sediment samples indicates that baseline resolution is achieved (R >1.5) for crocetane and phytane, with C-13-depleted crocetane delta C-13 values of -119.5 parts per thousand and -111.5 parts per thousand in the two natural samples, respectively) being an indicator of anaerobic oxidation of methane in cold seep areas. The new 2D-GC-IRMS method allows simple and efficient determination of the compound-specific carbon isotopic compositions of crocetane. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Hendricks, RachelReese, DanaFedesco, MarkChinn, Michael...
7页查看更多>>摘要：The development of manufacturing processes for antibody-drug conjugates (ADCs) presents many challenges compared to a standard monoclonal antibody. Conjugation processes typically start with an antibody intermediate that was purified to have very low levels of aggregates. The additional processing required for ADCs, including a hydrophobic small molecule and co-solvents, contributes to unacceptable levels of protein aggregate species. A post-conjugation purification step could be necessary to ensure that the process robustly delivers a product that achieves the desired product quality specifications. This paper describes a methodology for developing chromatographic purification steps to remove very high molecular weight species (vHMWS) in ADCs and was applied to three products, decreasing the vHMWS by >= 85% to <= 0.1%. Leveraging the antibody intermediate purification conditions to streamline development, we efficiently developed robust flow-through cation-exchange chromatography steps for ADC products. (c) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Souihi, AminaMohai, Miklos PeterPalm, EmmaMalm, Louise...
12页查看更多>>摘要：Structural elucidation of compounds detected with liquid chromatography coupled to high resolution mass spectrometry is a challenging and time-consuming step in the workflow of non-targeted analysis and often requires manual validation of the results. Retention time, alongside exact mass, isotope pattern, fragmentation spectra, and collision cross-section, is valuable information for ruling out unlikely structures and increasing the confidence in others. Different approaches to predict retention times have been used previously for reversed phase chromatography and hydrophilic interaction liquid chromatography (HILIC), but application is limited to a small set of mobile phases and gradient profiles. Here, we expand the toolbox available for retention time predictions by developing a random forest regression model for predicting retention times for four column types and twenty mobile phase systems. MultiConditionRT was built using a dataset containing 78 compounds analyzed with C18 reversed phase, mixed mode, HILIC, and biphenyl columns. In addition, different eluent compositions were used: both methanol and acetonitrile were combined with different aqueous phases with pH from 2.1 to 10.0 (formic acid, acetic acid, trifluoroacetic acid, formate, acetate, bicarbonate, and ammonia). The root mean square error (RMSE) of the test set predictions was 1.55 min for C18 reversed phase, 1.79 min for mixed-mode, 1.93 min for HILIC, and 1.56 min for biphenyl column. Additionally, MultiConditionRT can be applied to different gradient profiles with a general additive model-based calibration approach. The approach of MultiConditionRT was validated externally and internally with 356 and 151 compounds respectively, yielding an RMSE of 2.68 and 2.32 min. 324 and 84 of these compounds were not in the dataset used in the model development. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
原文链接:- NSTL
- Elsevier
Lossmann, KritHecht, RutaSaame, JaanHeering, Agnes...
8页查看更多>>摘要：This work explores the effects of three selected fluoroalcohols - 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), 1,1,1,3,3,3-hexafluorotert-butyl alcohol (HFTB) and hexafluoro-2,3-(trifluoromethyl)-2,3-butanediol (PP) as novel eluent additives and their effect on the retention of basic and acidic analytes, using a reversed phase (RP) column with a fluorophenyl (PFP) stationary phase. In order to observe the changes in the model analytes' retention, chromatograms were obtained at multiple (5.0; 6.0; 7.0; 8.5; 9.0 and 9.5) pH values depending on the eluent. The retention observed with fluoroalcohols was compared with that of a conventional eluent additive - ammonium acetate. When fluoroalcohols were used as eluent additives, a decrease in the retention factors (compared with ammonium acetate) was generally observed for strong acids. The retention factors of strong bases were generally higher when using HFIP and HFTB as eluent additives. The behaviour of weak bases and weak acids was more nuanced, potentially enabling interesting selectivity. The extent of the effect regarding different fluoroalcohols also varied, with HFIP and HFTB having a more significant effect on the retention of analytes than PP. The retention data were interpreted in terms of the hypothesis that four interactions are at play: (a) hydrophobic retention typical to RP; (b) pi-pi interactions between the analytes containing an aromatic ring and the aromatic rings on the stationary phase; (c) charge-charge or hydrogen bond interactions between the analytes and partially deprotonated fluoroalcohols adsorbed on the stationary phase and (d) a hydrogen bond or charge-charge interaction between the free silanol groups or their deprotonated forms on the stationary phase and the analytes (either neutral or ionic). Alternative selectivity obtained through fluoroalcohols on the PFP stationary phase was compared with the C18 and biphenyl stationary phases. It was demonstrated that at the same eluent pH but with a different buffer system and/or different RP stationary phases, very different selectivity and retention order can be obtained. (C) 2022 The Author(s). Published by Elsevier B.V.
原文链接:- NSTL
- Elsevier
