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[Display omitted] • A high SERS efficiency Au nanodendrite (AuND) structure was constructed by electro-deposition on a 3D nickel foam (NiF). • NiF with a highly porous structure and concave microchannel was employed as a sampling-diffusing medium. • AuND/NiF was situated onto a paper strip to construct a paper-based chromatography device (PP-AuND/NiF). • AuND/NiF substrate could detect R6G at 0.1 nM. • The PP-AuND/NiF could simultaneously separate and detect R6G in a mixture solution containing R6G and 2-NpSH. A simple paper-based chromatography coupling with nickel foam decorated Au nanodendrite (PP-AuND/NiF) was fabricated for simultaneous separation and surface-enhanced Raman scattering (SERS) detection of Rhodamine-6G (R6G) from a mixture of analytes. The three-dimensional porous nickel foam (NiF) was employed as a sampling diffusion platform, and AuND with a high surface active area beneficial for SERS efficiency was electro-deposited directly onto the NiF frame. The structure of AuND/NiF was characterized by X-ray diffraction and scanning electron microscopy. The AuND/NiF could detect R6G at 0.1 nM, and the enhancement factor was 1.84 x 106. The AuND/NiF was durable, with a slight signal decrease after 6 m of drop-testing. Also, upon three days of exposure to ambient air, the signal droped only 3.35 %. Subsequently, the PP-AuND/NiF was constructed by directly situating AuND/NiF on a paper strip, serving as a sample in and out to AuND/NiF. A mixture of two SERS active compounds, namely 2-Naphthalenethiol (2-NpSH) and Rhodamine 6G (R6G), was prepared in ethanol: water (1:1) solution to evaluate PP-AuND/NiF separation capability. Raman measurements along different distances of AuND/NiF were performed, and the signal of 2-NpSH was dismissed after 3.0 mm, while R6G's signals were observed throughout AuND/NiF. In general, the PP-AuND/NiF demonstrated effective separation and SERS measurement of analytes in a mixture, which could be applicable for more complex samples in the future, especially in clinical analysis. [ABSTRACT FROM AUTHOR]

• Recent advances in paper/thread-based zone and capillary electrophoresis techniques. • Various sample pretreatment methods using electrophoresis on wicking substrates. • Review of unmodified and modified microfluidic paper/threat -based chromatography. • Application of paper/threat -based chromatography in blood separation. Paper and thread are widely used as the substrates for fabricating low-cost, disposable, and portable microfluidic analytical devices used in clinical, environmental, and food safety monitoring. Concerning separation methods including chromatography and electrophoresis, these substrates provide unique platforms for developing portable devices. This review focuses on summarizing recent research on the miniaturization of the separation techniques using paper and thread. Preconcentration, purification, desalination, and separation of various analytes are achievable using electrophoresis and chromatography methods integrated with modified or unmodified paper/thread wicking channels. A variety of 2D and 3D designs of paper/thread platforms for zone electrophoresis, capillary electrophoresis, and modified/unmodified chromatography are discussed with emphasis on their limitation and improvements. The current progress in the signal amplification strategies such as isoelectric focusing, isotachophoresis, ion concentration polarization, isoelectric focusing, and stacking methods in paper-based devices are reviewed. Different strategies for chromatographic separations based on paper/thread will be explained. The separation of target species from complex samples and their determination by integration with other analytical methods like spectroscopy and electrochemistry are well-listed. Furthermore, the innovations for plasma and cell separation from blood as an important human biofluid are presented, and the related paper/thread modification methods are explored. [ABSTRACT FROM AUTHOR]

In this work, a novel analytical approach based on the photocatalytic decomposition of N -nitrosamines combined with headspace thin-film microextraction of the generated nitrogen oxides such as NO has been developed for the determination of the acyclic N -nitrosamine fraction in drinking water samples. A hydrophilic cellulose substrate modified with fluorescent silver nanoclusters (Ag NCs) was used both as extractant and sensing platform. A quenching effect of Ag NCs fluorescence occurs as the concentration of N -nitrosamines increases. Front-face fluorescence spectroscopy with a solid sample holder was employed for directly measuring the fluorescence quenching onto the cellulose substrate. In order to achieve an optimal analytical response, different parameters involved in the photocatalytic reaction as well as those concerning the microextraction step were fully investigated. It is demonstrated that the photodegradation rate of cyclic N -nitrosamines at acidic pH is much lower than that of acyclic ones, which can be the basis for the determination of the later fraction in waters. Under optimal conditions, a detection limit for the acyclic N -nitrosamine fraction around 0.08 μg L−1 using N -nitrosodimethylamine (NDMA) as model compound for calibration was obtained. Several drinking waters were spiked with acyclic N -nitrosamines showing recoveries in the range of 98–102% with a relative standard deviation of 3–4% (N = 3). N -nitrosamines generated as by-products during disinfection processes applied to water cause multiple adverse effects on human health being classified as potential human carcinogens. This study highlights the suitability of a fluorescent paper-based sensor for the rapid analysis of the acyclic N -nitrosamine fraction (i.e. the most abundant fraction) as a total index in drinking water, being useful as screening tool before exhaustive chromatographic analysis, which saves costs, time and reduces waste generation. [Display omitted] • In situ photocatalytic decomposition of N -nitrosamines to NO x species is performed. • Combination of microextraction with fluorescent paper-based sensing for NO x detection. • Ag NCs immobilized onto cellulose behave both as sorption and sensing platforms. • Front-face fluorescence spectroscopy as readout technique in the paper-based sensor. • A simple and rapid method for acyclic N -nitrosamines detection is accomplished. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells are immune cells that defend against viral infections and cancer and are used in cancer immunotherapies. Subpopulations of NK cells include CD56dim and CD56bright which either produce cytokines or cytotoxically kill cells directly. The absolute number and proportion of these cells in peripheral blood are tied to proper immune function. Current methods of cytokine detection and proportion of NK cell subpopulations require fluorescent dyes and highly specialized equipment, e.g., flow cytometry, thus rapid cell quantification and subpopulation analysis are needed in the clinical setting. Here, a smartphone-based device and a two-component paper microfluidic chip were used towards identifying NK cell subpopulation and inflammatory markers. One unit measured flow velocity via smartphone-captured video, determining cytokine (IL-2) and total NK cell concentrations in undiluted buffy coat blood samples. The other, single flow lane unit performs spatial separation of CD56dim and CD56bright and cells over its length using differential binding of anti-CD56 nanoparticles. A smartphone microscope combined with cloud-based machine learning predictive modeling (utilizing a random forest classification algorithm) analyzed both flow data and NK cell subpopulation differentiation. Limits of detection for cytokine and cell concentrations were 98 IU/mL and 68 cells/mL, respectively, and cell subpopulation analysis showed 89% accuracy. • First smartphone-based paper microfluidic cell chromatography that can identify cell subpopulation. • Machine learning predictive modeling for NK cell subpopulation differentiation. • Integration of both cell chromatography and flow rate analysis on a single platform. • Potential application to many other cytokines and cell subpopulation analyses. [ABSTRACT FROM AUTHOR]

• A method for detecting pesticides by combining TLC and enzyme inhibition was developed. • It reduced the effects of organic solvents and pigments in samples on rapid analysis. • The result of this method can be semiquantitative using smartphones and software. • It can sensitively determine dichlorvos, paraoxon and parathion in real samples. Herein, we developed a method coupling TLC and enzyme inhibition principles to rapidly detect OPs (dichlorvos, paraoxon and parathion). After the removal of the organic solvent from the samples using TLC and paper-based chips, the enzyme was added to the detection system. The results showed that the current method effectively reduced the effects of solvents on enzyme behavior. Moreover, the pigments could be successfully retained on TLC with 40% ddH 2 O/ACN solution (v/v) as a developing solvent. Additionally, the detection limits (LODs) were 0.002 µg/mL for dichlorvos, 0.006 µg/mL for paraoxon, and 0.003 µg/mL for parathion. Finally, the method was applied to spiked cabbage, cucumber, and spinach and showed good average recoveries ranging between 70.22% and 119.79%. These results showed that this paper-based chip had high sensitivity, precleaning, and elimination of organic solvent properties. Furthermore, it provides a valuable idea for sample pretreatment and rapid determination of pesticide residues in food. [ABSTRACT FROM AUTHOR]

Polygonum cuspidatum Sieb. et Zucc. is mainly distributed in Shanxi, Gansu, and Sichuan province of China. It is also found in Korea and Japan. Its dried roots and rhizomes are used as medicinal herbs and have been used to treat hyperglycemia and various inflammatory disorders. This paper aims to provide an up-to-date review of the developments in the studies involving the extraction and purification, structure analysis, pharmacological effects, and potential applications of polysaccharides obtained from Polygonum cuspidatum. Additionally, the possible future research directions of this plant are discussed. This article used " Polygonum cuspidatum polysaccharide (PCP)" and " Polygonum cuspidatum " as the keywords and gathered relevant data on Polygonum cuspidatum using electronic databases (Elsevier, PubMed, ACS, CNKI, Google Scholar, Baidu Scholar, Web of Science), relevant books, and classic literature about Chinese herb. Excluding irrelevant and repetitive documents, 278 documents were finally included, of which 88 were in Chinese and 190 were in English. The CiteSpace software was used to visualize the trends and keywords in this research field. We concluded that the main extraction methods for Polygonum cuspidatum polysaccharide are water extraction and alcohol precipitation, microwave-assisted extraction, ultrasound-assisted extraction, and microjet extraction. High-performance liquid chromatography and column chromatography are also commonly used in the separation and purification of PCP. PCP has antitumor, immunomodulatory, hypoglycemic, and antioxidant effects. This paper provides an updated and deeper understanding of PCP, serving as a theoretical foundation for the further optimization of polysaccharide structures and the development of PCP as a novel functional material for clinical application. [Display omitted] [ABSTRACT FROM AUTHOR]

• An alternative elution mode to conventional HPLC to separate compounds by class. • Sequential elution was utilized to separate classes of compounds in under 15 min. • A tandem-column stationary phase combination (SAX and C18) was utilized. • SAX+C18 and C18+SAX column orientations yielded nearly identical separations. • Retention time and peak area precision were below 1.5 % RSD. This paper discusses the development of an analytical method by an alternative separation approach, sequential elution liquid chromatography (SE-LC), to separate permanently charged ions (anions), weak acids, and neutral compounds using anion exchange and reversed-phase columns in tandem. SE-LC separates classes of compounds by group by employing two or more elution modes. Advantages to using SE-LC over conventional HPLC are a greater peak capacity and a reduced separation disorder. Importantly, the same HPLC as used for a conventional HPLC separation may be used to afford a successful SE-LC separation. Mobile phase selection and gradient optimization are integral for a successful SE-LC class separation of permanent anions, weak acids, and neutral compounds and will be discussed in detail in this paper. The most successful (best resolution and repeatability) SE-LC separation was achieved by applying isocratic elution at low pH to elute the weak acids, followed by an acetonitrile gradient to elute the neutral compounds, and last a sodium methanesulfonate gradient to elute the anionic compounds using a superficially porous C18 column coupled with a strong anion exchange (SAX) column. Repeatability (RSD) in the retention times and peak areas of the analytes was less than 0.25 % and 1.5 %, respectively. [ABSTRACT FROM AUTHOR]

Despite the rise of digitalization, the scrutiny of paper documents with stamps and signatures remains crucial, constituting 55–60 % of document examination court cases. Developing accessible and robust ink analysis techniques is an ongoing challenge for forensic scientists. To tackle issues related to the identification and classification of dye components in blue ballpoint pens, we have proposed an advanced approach that integrates high-performance thin-layer chromatography (HPTLC), digital color analysis (DCA), and hierarchical cluster analysis (HCA) for a simplified yet effective procedure. The method encompasses multiple development of TLC plates. Initial separation employs methanol:ethanol (4:1, v/v), followed by a second separation using methanol:propan-2-ol:formic acid (1:1:0.1, v/v/v) to achieve cationic dye separation. This TLC development enhances separation selectivity, contributing to a more precise clustering of pen inks. Employing advanced DCA as a processing method for HPTLC, the optimal descriptor for ink classification is identified as the difference between red (R) and green (G) color components. The proposed clustering algorithm achieved 8 distinct ink clusters, showing improved discriminative capability and a reduced variable space compared to well-established or state-of-the-art methods. The approach's robustness was demonstrated across different readout devices, including smartphones and scanners. Reproducibility tests yielded consistent clustering results, confirming the method's reliability. Moreover, the method proved effective in clustering pen ink extracts from paper substrates, showcasing its potential for real sample analysis. This HPTLC-DCA approach presents a simple, cost-effective, and high-precision solution for clustering blue pen inks, significantly enhancing accessibility in high-throughput forensic applications. [Display omitted] • Utilized multiple development HPTLC for enhanced separation selectivity. • Integrated phthalocyanine dyes for enhanced ink analysis precision. • Achieved robust clustering across various readout devices. • Demonstrated applicability in clustering pen ink extracts from paper substrates. [ABSTRACT FROM AUTHOR]

Process development is typically associated with lengthy wet-lab experiments for the identification of good candidate setups and operating conditions. In this paper, we present the key features of a model-based approach for the identification and assessment of process design space (DSp), integrating the analysis of process performance and flexibility. The presented approach comprises three main steps: (1) model development & problem formulation, (2) DSp identification, and (3) DSp analysis. We demonstrate how such an approach can be used for the identification of acceptable operating spaces that enable the assessment of different operating points and quantification of process flexibility. The above steps are demonstrated on Protein A chromatographic purification of antibody-based therapeutics used in biopharmaceutical manufacturing. • Model-based approach for quantitative design space characterization. • Integrated assessment of design decisions, operating variables and process variabilities. • Application to chromatographic unit operation. [ABSTRACT FROM AUTHOR]

Complex systems exist widely, including medicines from natural products, functional foods, and biological samples. The biological activity of complex systems is often the result of the synergistic effect of multiple components. In the quality evaluation of complex samples, multicomponent quantitative analysis (MCQA) is usually needed. To overcome the difficulty in obtaining standard products, scholars have proposed achieving MCQA through the "single standard to determine multiple components (SSDMC)" approach. This method has been used in the determination of multicomponent content in natural source drugs and the analysis of impurities in chemical drugs and has been included in the Chinese Pharmacopoeia. Depending on a convenient (ultra) high-performance liquid chromatography method, how can the repeatability and robustness of the MCQA method be improved? How can the chromatography conditions be optimized to improve the number of quantitative components? How can computer software technology be introduced to improve the efficiency of multicomponent analysis (MCA)? These are the key problems that remain to be solved in practical MCQA. First, this review article summarizes the calculation methods of relative correction factors in the SSDMC approach in the past five years, as well as the method robustness and accuracy evaluation. Second, it also summarizes methods to improve peak capacity and quantitative accuracy in MCA, including column selection and two-dimensional chromatographic analysis technology. Finally, computer software technologies for predicting chromatographic conditions and analytical parameters are introduced, which provides an idea for intelligent method development in MCA. This paper aims to provide methodological ideas for the improvement of complex system analysis, especially MCQA. [Display omitted] SSDMC: single standard to determine multiple components; RCF: relative correction factor; 2D-LC: Two dimensional liquid chromatography; CSASS: complex sample analysis software system; QSRR: quantitative structure-retention relationship. • Reviewing development progress of SSDMC method in complex system analysis. • Reviewing chromatographic columns selection and 2D-LC analysis method construction. • Summarizing computer-aided techniques for predicting chromatographic analytical parameters. • Predicting future development direction of MCQA. [ABSTRACT FROM AUTHOR]

Aflatoxin B 1 (AFB 1) is an extremely toxic food contaminant that has serious effects on human health. In published aptamer-based lateral flow chromatography test strips, the detection results are mostly inversely proportional to the concentration of AFB 1 , which is a serious violation of intuition. An aptamer sensor based on the "turn on" mode for AFB 1 detection has been reported in this paper. In this paper, we use gold nanoparticles (AuNPs) to present colorimetric signals and link capture sequences (SH-poly A-cDNA) to design AuNPs@SH-poly A-cDNA nanoprobes. The test strip relies on AFB 1 and AuNPs@SH-poly A-cDNA competing aptamers for rapid detection of AFB 1. In the absence of AFB 1 , the aptamer binds to AuNPs@SH-poly A-cDNA, preventing the cDNA from binding to the complementary fragment of the test line (DNA T), resulting in the disappearance of the red signal. However, in the presence of AFB 1 , the aptamer binds to AFB 1 , allowing some AuNPs@SH-poly A-cDNA not bound to the aptamer to be captured by DNA T , leading to the generation of a red signal. Regardless of the presence or absence of AFB 1 , the poly-A fragment of AuNPs@SH-poly A-cDNA consistently binds to the complementary sequence of the control line (DNA C) and presents a red signal. The detection results are proportional to the concentration of AFB 1 , which is in line with human intuitions. The development of this test strip provides a novel design idea for the detection of small molecules such as mycotoxins. • Innovative application of aptamer in test strips for the detection of AFB 1. • The first "turn on" mode for AFB 1 detection using AuNPs as signal labels. • "Turn on" mode meets the intuitive impression and has comparable detection limits. • The aptamer and complementary sequences on detection results was investigated. [ABSTRACT FROM AUTHOR]

• A strategy to improve host cell protein clearance in the downstream process for therapeutic proteins using multimodal chromatography. • High throughput process development workflow used to screen resins at the polishing step and multimodal chromatography resin Nuvia cPrime identified as a promising candidate. • Host cell proteins eluted at a lower salt concentration than the therapeutic protein over multimodal chromatography when operated in bind/elute mode. • An intermediate low salt wash step on Nuvia cPrime enabled clearance of 80 % of host cell proteins including some known to be problematic and difficult-to-remove. In biotherapeutic protein production, host cell proteins (HCPs) are one of the main process related impurities which must be cleared and controlled through downstream processing. In this paper, we studied a novel therapeutic protein molecule which had a high level of HCP co-purification throughout the downstream process. Here, we focused on the polishing purification step and developed an effective strategy for improving HCP clearance using multimodal chromatography (MMC) resin, Nuvia cPrime. A high throughput process development (HTPD) workflow was used to identify the resin and process conditions which could enable significant HCP clearance while maintaining acceptable product quality and process performance. HCP analysis of gradient elution fractions on multimodal chromatography found that HCPs eluted at the beginning of the gradient, at a lower salt concentration than the therapeutic protein. Based on these findings, a step elution process involving an intermediate low salt wash was developed to clear weak-binding HCPs, while retaining the therapeutic protein on the column. This strategy was highly effective and enabled 80 % reduction in total HCP content, including some problematic and difficult to remove candidates such as Peroxiredoxin-1, Serine protease HTRA1, Clusterin and Lipoprotein lipase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Composition of Δ8-THC solutions converted from CBD by eight protocols was investigated. • Three orthogonal chromatographic methods were developed. • Distinct ESI and EI spectra towards five THC isomers were reported. • Multiple THC isomers were found in acid-treated CBD samples and Δ8-THC-infused edibles. Δ8-Tetrahydrocannabinol (Δ8-THC) is increasingly popular as a controversial substitute for Δ9-tetrahydrocannabinol (Δ9-THC) in cannabinoid-infused edibles. Δ8-THC is prepared from cannabidiol (CBD) by treatment with acids. Side products including Δ9-THC and other isomers that might end up in Δ8-THC edibles are less studied. In this paper, three orthogonal methods, namely reversed-phase (RP)-UHPLC-DAD/HRMS, normal-phase/argentation (silica-Ag(I))-HPLC-DAD/MS, and GC-FID/MS were developed for analysis of cannabinoid isomers, namely Δ8-THC, Δ9-THC, CBD, Δ8-iso-THC, Δ(4)8-iso-THC, and hydrated THC isomers. Eight acid-treated CBD mixtures contained various amounts of Δ8-THC (0–89%, w/w%), high levels of Δ9-THC (up to 49%), Δ8-isoTHC (up to 55%), Δ(4)8-iso-THC (up to 17%), and three hydrated THC isomers. Commercial Δ8-THC gummies were also analyzed, and issues like overclaimed Δ8-THC, excessive Δ9-THC, undeclared Δ8-iso-THC, and Δ(4)8-iso-THC were found. These findings highlight the urgency of improving regulations towards converting CBD to Δ8-THC for use as food ingredients. [ABSTRACT FROM AUTHOR]

The unceasing evolution of analytical instrumentation determines an exponential increase of data production, which in turn boosts new cutting-edge analytical challenges, requiring a progressive integration of artificial intelligence (AI) algorithms into the instrumental data treatment software. Machine learning, deep learning, and computer vision are the most common techniques adopted to exploit the information potential of advanced analytical chemistry measures. In this paper, our primary focus is on elucidating the remarkable advantages of leveraging AI tools for comprehensive two-dimensional gas chromatography data (pre)processing. We illustrate how AI techniques can efficiently explore the complex datasets derived from multidimensional platforms combining comprehensive two-dimensional separations with mass spectrometry in the challenging application area of food-omics. Pattern recognition based on image processing, computer vision, and AI smelling are discussed by introducing the principles of operation, reviewing available tools and software solutions, and illustrating their potentials and limitations through selected applications. • Artificial Intelligence boost the informative potential of GC × GC. • Computer Vision based on chromatogram images. • AI smelling machine with GC × GC-MS predicts food aroma properties. • Advancing the explorative potential of comprehensive two-dimensional chromatography. • Augmented visualization combines visual features with chemical information. [ABSTRACT FROM AUTHOR]

• Performance comparison of membrane chromatography devices based on CFD. • Use of solute dispersion as indicator of separation performance. • Rapid screening and optimization membrane chromatography device design. • Development of a strategy for process improvement. Flow uniformity within the device is critically important in membrane chromatography. Recent studies have shown that the design of the device has a significant impact on flow uniformity, and thereby on separation efficiency. The main premise of this work is that computational fluid dynamics (CFD) could serve as a fast and inexpensive tool for preliminary optimization of the design of a membrane chromatography device. CFD also helps in identifying factors that affect flow uniformity. In this paper, CFD is used to compare the fluidic attributes of conventional membrane chromatography devices such as the stacked disc and radial flow devices with those of more recently developed ones such as the different versions of the laterally-fed membrane chromatography (LFMC) device. These are compared based on pulse tracer solute dispersion, which is a useful metric for measuring flow uniformity, and is thereby a good predictor of chromatographic separation performance. The poor separation performance typically observed with conventional membrane chromatography devices could be attributed to the high degree of solute dispersion within these devices. CFD is then used to analyze the impact of factors such as membrane aspect ratio, and channel dimensions on the performance of z2-laterally-fed membrane chromatography (z2LFMC) devices. The results discussed in the paper demonstrate that CFD could indeed serve as a powerful optimization and performance prediction tool for membrane chromatography. [ABSTRACT FROM AUTHOR]

• Two-dimensional separations enable peak purity analysis of pharmaceutical peptides. • Strategy to derive second-dimension gradient conditions. • Preferred gradient conditions discovered by retention modelling. The importance of therapeutic peptides continues to increase in the marketplace for treating a range of diseases including diabetes and obesity. Quality control analyses for these pharmaceutical ingredients usually depends on reversed-phase liquid chromatography, and it is critically important to ensure that no impurities coelute with the target peptide at levels that would compromise the safety or effectiveness of the drug products. This can be challenging due to the broad range of properties of impurities that can be present on one hand (e.g., amino acid substitutions, chain cleavages, etc.), and the similarity of other impurities on the other hand (e.g., d -/ l -isomers). Two-dimensional liquid chromatography (2D-LC) is a powerful analytical tool that is well suited to address this particular problem; the first dimension can be used to detect impurities over a broad range in properties, while the second dimension can be used to focus specifically on those species that might coelute with the target peptide in the first dimension. While hundreds of papers have been published on the use of 2D-LC for proteomics applications, there are very few papers that have focused on its use for characterisation of therapeutic peptides. This paper is the second in a two-part series. In Part I of the series, we studied several different column / mobile phase combinations that could be useful in 2D-LC separations of therapeutic peptides, with a focus on selectivity, peak shape, and complementarity to other combinations, particularly for isomeric peptides under mass spectrometry-friendly conditions (i.e., volatile buffers). In this second part in the series, we describe a strategy to derive second-dimension (2D) gradient conditions that both, ensure elution from the 2D column, and increase the likelihood of resolving peptides with very similar properties. We find that a two-step process yields conditions that place the target peptide in the middle of the 2D chromatogram. This process begins with two scouting gradient elution conditions in the second dimension of a 2D-LC system, followed by building and refining a retention model for the target peptide using a third separation. The process is shown to be generically useful by developing methods for four model peptides, and application to a sample of degraded model peptide to demonstrate its utility for resolving impurities in a real sample. [ABSTRACT FROM AUTHOR]

The analysis of chlorinated paraffins (CPs) has become a major analytical challenge. GC-ECNI-HRMS coupling is often used to analyse and quantify them. However, the influence of certain GC and ECNI parameters on the responses of polychlorinated n -alkanes (PCAs), the dominant components of CPs, has hardly been studied. In this paper, we investigated not only the influence of GC column characteristics, but also oven, GC inlet and source temperatures for simultaneous analysis of PCAs with chain-length ranging from 10 up to 20 carbon atoms (PCAs–C 10-20). Particular attention was paid to the absolute response and PCA homologue group pattern obtained for a CP technical mixture. The optimum conditions for a wide homologue group determination were GC inlet, final gradient and ion source temperatures set at 220–240 °C, 340 °C and 200 °C. At the same time, a higher response was obtained with the Optima 5HT column compared to Optima 1 column, and with a length and film thickness of 12.5 m and 0.25 μm, respectively. The homologue group pattern of the technical mixture studied was significantly modified as a function of the source and GC inlet temperatures, film thickness and composition of the stationary phase. Here we recommend conditions that will improve the overall PCA pattern, in order to better characterise their occurrence in future environmental monitoring and exposure assessment. [Display omitted] • PCAs were detected up to C 20 using the optimised GC-ECNI-HRMS method. • Influence of GC and ECNI parameters on PCA patterns were revealed. • Ion source temperatures above 250 °C lead to possible formation of PCOs. • Degradation of heaviest PCAs may occur at elevated inlet source temperatures. [ABSTRACT FROM AUTHOR]

The current HPLC methods for the quantification of vitamin D 3 (VitD 3) and its two isomers previtamin D 3 (PreVitD 3) and trans -vitamin D 3 (trans -VitD 3) in olive oil preparations present some limitations mainly due to peak overlapping of the oily matrix components with the compounds of interest. The use of two-dimensional liquid chromatography (2D-LC) with different retention mechanism can reach higher resolving power thus allowing the analysis of complex samples. The present paper proposes a new alternative method including a solid phase extraction sample preparation step and a two-dimensional liquid chromatographic analysis using routine instrumentation, fitting the needs of quality assurance and quality control laboratories of pharmaceutical companies. The extraction protocol was demonstrated to provide a clean-up of the sample and a quantitative recovery of the species of interest. The 2D method proved its suitability in the isolation of vitamins from oil components in the first dimension and the separation and quantification of the analytes in the second dimension thanks to the orthogonal selectivities of phenyl and porous graphitic carbon (PGC) stationary phases. The method was validated following ICH guidelines and possesses an adequate sensitivity to quantify the impurity trans -VitD 3 in pharmaceuticals considering the limits imposed by regulatory agencies. The applicability of the phenyl x PGC 2D-LC-UV method to quality control of medicinal products based on VitD 3 in olive oil was confirmed by the successful quantification of vitamins in olive oil formulations. [Display omitted] • A phenyl x PGC 2D-LC-UV method was developed to separate vitamin D 3 and its isomers. • Solid phase extraction allowed to quantitatively isolate vitamins from the olive oil matrix. • Phenyl and porous graphitic carbon columns were coupled on-line for the first time. • The two-dimensional chromatographic method was validated following ICH guidelines. • The method is suitable for quality control of vitamin D 3 in olive oil formulations. [ABSTRACT FROM AUTHOR]

for the analysis of cannabinoids in bio-matrices are continually improved to achieve best possible sensitivity in their detection and accurate quantification. It has been well documented that CBD cyclizes to Δ9-THC and Δ9-THC isomerizes to Δ8-THC under acidic conditions by means of a Lewis-acid-catalyzed process, causing difficulty in accurate quantification of Δ9-THC in the presence of CBD, of CBD itself and of Δ9-THC itself when these compounds have to be derivatized by acylation. The present paper shows that CBD cyclization and Δ9-THC isomerization can be blocked by tertiary amines or azines, which capture protons appearing in the derivatizing mixture during acylation. The efficiency of the described acylation of CBD depends on the time and temperature of the derivatizing process, whereas the degree of CBD acylation, i.e. the synthesis of mono- or di-acylate CBD derivative, depends on the mutual ratio of the cannabinoid, the acylating agent and the proton binding compound. The way of mono- and di-acyl CBD derivatives formation described in the paper has not been reported yet. The paper contains a comprehensive analytical characterization of two types of CBD acyl derivatives, CBD-TFA and CBD-Ac, obtained by NMR, GC–MS and LC–MS. [Display omitted] • CBD cyclization and Δ9-THC isomerization can be blocked by tertiary amines or azines. • CBD acylation degree depends on the ratio of CBD, acylating agent and proton-binder. • Comprehensive analytical characterization of mono- and diacyl CBD and THC derivatives. [ABSTRACT FROM AUTHOR]

The development of analytical techniques in the field of liquid chromatography has brought new frontiers in performance and analytical speed for the technique. The proper evaluation of the analytical boundaries achieved with those developments was not addressed in the literature, since different liquid chromatography (LC) techniques have not yet received any classification regarding their chromatographic speed. Defining chromatographic analysis speed based simply on analysis time is an outdated concept since it is sample and analyte-dependent. In this context, the application of the Average Theoretical Peak Time concept (ATPT) is proposed as a unified metric for chromatographic speed classification. This metric was evaluated using PCA analysis in a group of more than 50 publications, which generated the classification of LC methods in normal, high, hyper, and ultra-high-speed separations using ATPT. Normal speed (ATPT values greater than 18000 ms/peak) was found in HPLC, nano-LC, SFC, and CEC methods. Therefore, high-speed methods (ATPT values between 4000 and 18000 ms/peak) were found in UHPLC techniques, while LC × LC methods presented higher ATPT values between 1000 and 4000 ms/peak being classified as hyper-speed separations. ATPT can also be used as an optimization parameter, since older methods show higher ATPT values, while recent published papers show lower values of this metric. This behavior is justified due to the improvement of the LC methods over the years. This work fulfills the gap in chromatographic definitions and metrics, regarding analytical speed in one-dimensional and multidimensional liquid chromatographic techniques and shows that ATPT metrics is a robust parameter that can be used to classify the separation speed as well as a metric to evaluate the LC Method optimization. It also corrects the historical application of separation time as a metric for chromatographic speed. [Display omitted] • Chromatographic separation speed should not be defined based on separation time. • ATPT was defined using appropriate speed metric according to proprietary equations. • The qualitative parameters PCA was used to classify the LC speed based on ATPT. • ATPT metric was applied in several LC methods, including SFC, CEC, and LC × LC. • ATPT is a new method development tool for all chromatographic techniques. [ABSTRACT FROM AUTHOR]

In this paper, the determination of both oxidizable and reducible compounds within a single chromatographic run is exploited for the first time, using a low-pressure chromatographic system and multiple pulse amperometric detection. The case study selected focussed on the analysis of green coffee extracts. The separation of the compounds was carried out using a 1-cm length monolithic column and an eluent prepared by mixing an aqueous solution of an ion-pair reagent, perfluoroheptanoic acid (PFHpA), and acetonitrile. The parallel determination of oxidizable and reducible compounds was performed by application of two consecutive pulses, E 1 = +1.6 V and E 2 = −1.5 V. At anodic conditions, the chromatographic peaks for 5-caffeoylquinic acid (5-CQA), caffeine and 5-feruloylquinic acid (5-FQA) were detected, while at cathodic conditions, a chromatographic peak was ascribed for trigonelline. In the developed methodology, the use of multiple pulse amperometry provided better sensitivity if compared to previously described amperometric methodologies determining either oxidizable or reducible compounds. Detection limits for the referred compounds of ca. 1 × 10−5 mol L−1, an analysis rate of 12 h−1 and an acetonitrile consumption of 0.07 mL per analysis were achieved. The approach presented demonstrates the possibility of combining low pressure chromatographic systems and multiple pulse amperometry, in the development of new, low-cost and fast methodologies for multi-analyte determinations. [Display omitted] • Parallel determination of oxidizable and reducible compounds. • Multiple pulse amperometry in low pressure chromatographic systems. • Determination of trigonelline, 5-CQA, caffeine and 5-FQA in green coffee extracts. • Analysis rate of 12 samples·h−1 and acetonitrile consumption of 0.07 mL·sample−1. [ABSTRACT FROM AUTHOR]

In recent years, there have been numerous incidents of serious accidents related to impurities of optical isomers, particularly in pharmaceutical treatment, environmental problems, and pesticide application. Among these impurities, chiral epichlorohydrin (ECH) is an important C3 synthon and a potentially genotoxic impurity. The enantiopure forms of S-ECH and R-ECH are key raw materials for synthesizing many drugs, which make it important to accurately quantify the specific conformation of chiral epichlorohydrin in pharmaceuticals. In this paper, we achieved the separation of chiral ECH by gas chromatography (GC) and based on the combination of vibrational circular dichroism (VCD) experiments and theoretical calculations, the qualitative method of chiral ECH was achieved without relying on a single enantiomeric standard. [Display omitted] • By comparing the theoretical VCD spectra of the single ECH enantiomer with the experimental VCD spectra of the R/S-ECH mixture, the configuration of the dominant enantiomer in the nonracemic mixture was determined. • Combined theoretical and experimental VCD spectra with GC, the peak of R/S-ECH in GC was successfully identified. A GC method for the determination of chiral ECH independent of a single enantiomer standard is first proposed. • The concentration of the single ECH enantiomer in the mixture can be accurately quantified. [ABSTRACT FROM AUTHOR]

Sample pretreatment plays a vital role in determining and analyzing targets in complex samples like food, biological, and environmental samples. Particularly, graphene and graphene oxide have been widely explored as sorbents in sample preparation. More recently, their composites with magnetic materials, molecularly imprinted polymers, metal-organic frameworks, covalent organic frameworks, aerogels, and other materials have also been developed for sample preparation. Interestingly, these composites enhanced enrichment and selectivity towards different types of analytes by multiple mechanisms including hydrogen bonding, π-stacking, electrostatic, hydrophobic, and hydrophilic effects. Primarily, this review focuses on the recent development of graphene/graphene oxide-based sorbents in solid-phase extraction (SPE) and solid-phase microextraction (SPME) from 2017 to 2022. The main extraction techniques in this paper include column SPE, dispersive SPE, magnetic SPE, pipette-tip SPE, fiber SPME, in-tube SPME, etc. Meanwhile, the current problems and prospects are summarized and described. • The recent advances of G/GO-based sorbents in SPE are summarized. • The applications of G/GO-based sorbents in SPME are overviewed. • The extraction mechanism of G/GO-based materials is described. • The analysis of various targets in different samples is reviewed. • Prospects and challenges of G/GO-based extraction materials are discussed. [ABSTRACT FROM AUTHOR]

Chromatographic enantioseparation on polysaccharide-based chiral stationary phases has undergone explosive development over the last three decades as a method for separating the enantiomers of chiral compounds on an analytical and preparative scale. In this context, understanding the nature of the intermolecular interactions involved in retention and recognition processes is an interesting scientific challenge. In the present study, three eugenol derivatives were used as chiral references to elucidate some unexplored aspects of the enantioselective and retention properties of the Chiralpak IG-U chiral stationary phase based on amylose-tris(3-chloro-5-methylphenylcarbamate). The performance of the ultra-high performance liquid chromatography chiral packing material Chiralpak IG-U was evaluated using a two-step approach. First, binary mixtures containing variable proportions of alcohol (ethanol or 2-propanol) in n-hexane were used as mobile phases and the retention factors were recorded at three different temperatures. A rational analysis of this set of chromatographic data shows the leading role played by hydrogen bond between the OH group linked to the stereogenic centre of the analytes and the active sites of the chiral chromatographic material in obtaining a high degree of enantioseparation. The retention factors were then plotted against the percentage of alcohol modifiers to obtain retention maps with a non-linear performance trend with correlation factors >0.9990. The proposed retention map model was used to extrapolate and describe virtual chiral recognition of chiral analytes on the Chiralpak IG-U chiral stationary phase under extreme elution conditions with expected run times of hundreds or thousands of years. The presented virtual chiral recognition approach is based on a generic concept and therefore opens new possibilities for understanding the performance of other polysaccharide-based chiral stationary phases. [Display omitted] • This paper describes the HPLC behavior of chiral eugenol derivatives on the IG-U CSP. • Mixtures with variable proportions of EtOH or IPA in n-hexane were used as eluents. • H-bond was the key interaction for obtaining high retention and enantioselectivity. • Retention maps were used to study chiral recognition in extreme elution conditions. • Run times of hundreds or thousands of years were predicted for very low EtOH content. [ABSTRACT FROM AUTHOR]

• Model-assisted approaches for continuous chromatograph were reviewed. • Model-assisted methods for process development were focused and discussed. • Strategies for model-assisted process characterization was proposed. • Current model-assisted process design approaches were reviewed. • Perspectives of model-assisted tools for the future digitalized manufacturing were discussed. Continuous manufacturing in monoclonal antibody production has generated increased interest due to its consistent quality, high productivity, high equipment utilization, and low cost. One of the major challenges in realizing continuous biological manufacturing lies in implementing continuous chromatography. Given the complex operation mode and various operation parameters, it is challenging to develop a continuous process. Due to the process parameters being mainly determined by the breakthrough curves and elution behaviors, chromatographic modeling has gradually been used to assist in process development and characterization. Model-assisted approaches could realize multi-parameter interaction investigation and multi-objective optimization by integrating continuous process models. These approaches could reduce time and resource consumption while achieving a comprehensive and systematic understanding of the process. This paper reviews the application of modeling tools in continuous chromatography process development, characterization and design. Model-assisted process development approaches for continuous capture and polishing steps are introduced and summarized. The challenges and potential of model-assisted process characterization are discussed, emphasizing the need for further research on the design space determination strategy and parameter robustness analysis method. Additionally, some model applications for process design were highlighted to promote the establishment of the process optimization and process simulation platform. [ABSTRACT FROM AUTHOR]

The sensitivity of complex analytical procedures depends not only on the sensitivity of the analytical instrument used, but also on the recovery degree of the examined analyte by the employed sample preparation method. The recovery degrees of individual cannabinoids reported in literature, estimated using the same sample preparation method, are unexpectedly divergent. Therefore, the aim of this study was a thorough assessment of the most commonly used sample preparation methods, such as protein precipitation, LLE, QuEChERS and SPE, in the context of the reliability of the obtained results. The presented report shows that the highest sensitivity, precision and reliability of the chromatographic analysis of CBG, CBD, ∆9-THC and CBN in human plasma can be obtained using SPE. The recovery degrees of these cannabinoids by SPE are highly repeatable and exceed 95 %, while they are significantly lower for such sample preparation methods as protein precipitation, LLE and QuEChERS (ca. 80, 65 and 87, respectively). Moreover, the supernatants obtained by the latter methods contain interferents evoking matrix-effect, which makes reliable quantification of the listed cannabinoids by GC difficult. To our knowledge, the paper is the first such extensive comparison of sample preparation procedures used for the determination of cannabinoids in plasma by GC-MS and HPLC-MS. The presented results and the discussion allow to understand why different recovery degrees for the same xenobiotic can be find in literature despite they have been estimated using the same or different sample preparation method or different chromatography types. [Display omitted] • Analyte recovery degree as a key factor in analytical procedure of complex mixtures. • SPE gives almost 100 % recovery of cannabinoids from blood plasma. • SPE allows for reliable analysis of cannabinoids in blood/plasma by GC and HPLC. • Plasma LLE and QuEChERS supernatants contain interferents evoking matrix effect in GC. [ABSTRACT FROM AUTHOR]

• Membrane chromatography for large viral particles purification. • Multi-membrane chromatography through periodic counter current method. • Continuous manufacturing for viral vaccines. Continuous multi-column chromatography (CMCC) has been successfully implemented to address biopharmaceutical biomolecule instability, to improve process efficiency, and to reduce facility footprint and capital cost. This paper explores the implementation of a continuous multi-membrane chromatography (CMMC) process, using four membrane units, for a large viral particle in just few weeks. CMMC improves the efficiency of the chromatography step by enabling higher loads with smaller membranes for multiple cycles of column use and enables steady-state continuous bioprocessing. The separation performance of CMMC was compared to a conventional batch chromatographic capture step used at full manufacturing scale. The product step yield was 80% using CMMC versus 65% in batch mode while increasing slightly the relative purity. Furthermore, the total amount of membrane area required for the CMMC approach was approximately 10% of the area needed for batch operation, while realizing similar processing times. Since CMMC uses smaller membrane sizes, it can take advantage of the high flow rates achievable for membrane chromatography that are not typically possible at larger membrane scales due to skid flow rate limitations. As such, CMMC offers the potential for more efficient and cost-effective purification trains. [ABSTRACT FROM AUTHOR]

[Display omitted] • Semi-empiricalMMC model accounting for both pH and organic modifier effects. • Retention trends across the entire tested pH/organic-modifier 2D space. • Benchmarked against small organic probes of various types. • The key role of dissociated silanol groups on the silica support was revealed. • Competition of cation-exchange and anion-exchange retention mechanism was described. Mixed-mode chromatography is a widely used analytical method that utilizes multiple separation mechanisms in one chromatographic column; frequently a reversed-phase and ion-exchange interactions. Adequate understanding of how the individual interactions influence the overall retention of the analyte is important for fast and effective design of mixed-mode-based methods. Previous attempts to derive semi-empirical mathematical models of mixed-mode chromatography were limited to a narrow range of analytes and did not consider the effect of organic modifier in the mobile phase. In this paper, we attempt to improve upon the previous models by extending the range of classes of analytes to weak acids and bases and including the effect of organic modifier. An improved semi-empirical model was derived that captures all important retention trends of the combined effect of reversed-phase and ion-exchange retention mechanisms for all tested classes of analytes and up to 30% (v/v) organic modifier content. [ABSTRACT FROM AUTHOR]

• Rapid iterative optimization of multimodal ligands with improved mAb selectivity. • Ligand structure mapping: Predicted descriptors of a virtual library guides synthesis. • Chromatographic mapping: HTPD screening of protein binding vs. pH and conductivity. • Quantified multimodal interactions: Isocratic retention factor analysis. • A workflow connecting ligand structure, HTPD binding, and chromatogram modelling. Multimodal chromatography resins are becoming a key tool in the purification of biomolecules. The main objective of this research was the establishment of an iterative framework for the rapid development of new multimodal resins to provide novel selectivity for the future purification challenges. A large chemically diverse virtual library of 100 multimodal Capto™ MMC ligand analogues was created, and a broad array of chemical descriptors were calculated for each ligand in silico. Principal component analysis (PCA) was used to map the chemical diversity and guide selection of ligands for synthesis and coupling to the Capto ImpRes agarose base matrix. Twelve new ligands were prepared in two groups: 'group one' consist of L00-L07 and 'group two' consist of L08-L12. These ligands are diverse in the influence of varied secondary interactions such as hydrophobic interactions, H-bonding, etc. Additional resin prototypes were also prepared to look at the chromatographic impact of ligand density variation. High-throughput plate-based studies were performed for parallel resin screening for batch-binding of six model proteins at different chromatographic binding pH and sodium chloride concentration conditions. Principal component analysis of the binding data provided a chromatographic diversity map leading to the identification of ligands with improved binding. Further, the new ligands have improved separation resolution between a monoclonal antibody (mAb1) and product related impurities, a Fab fragment and high molecular weight (HMW) aggregates, using linear salt gradient elutions. To quantify the importance of secondary interactions, analysis of the retention factor of mAb1 on the ligands at various isocratic conditions lead to estimations of (a) the total number of water molecules and counter salt ions released during adsorption, and (b) hydrophobic contact area (HCA). The iterative mapping approach of chemical and chromatography diversity maps described in the paper proves to be a promising method for identifying new chromatography ligands for biopharmaceutical purification challenges. [ABSTRACT FROM AUTHOR]

• Four AEX Resins were selected using the HTPD platform resulting in sample consumption and time-saving. • The single-step anion exchange chromatography allows high capacity and effective clearance of the homodimer byproduct to be simultaneously under achieved weak partitioning mode. • Robust windows of operation were efficiently developed for bsAb purification by leveraging the design of experiments. Small amounts of by-products are nevertheless created during the recombinant production of IgG-like bispecific antibodies due to imbalanced chain expression and improper chain pairing, despite the employment of molecular strategy techniques to promote accurate pairing. Among them, homodimers represent the species that are more difficult to remove due to their physical and chemical properties being similar to the target antibody. Homodimer by-products are always produced even though various technologies can significantly increase the expression of heterodimers, so a robust purification process to recover high-purity heterodimers is required. Most of the chromatography methods commonly adopt the bind-and-elute mode or two-step to separate homodimers, which has numerous drawbacks such as prolonged process times and limited dynamic binding capacity. Flow-through mode of anion exchange is a frequently-used polishing step for antibodies, but it is typically regarded as being more effective for host-cell protein or host-cell DNA removal rather than other product-related impurities such as homodimers and aggregates. This paper demonstrated that single-step anion exchange chromatography allows high capacity and effective clearance of the homodimer byproduct to be simultaneously achieved, suggesting that weak partitioning was a better polishing strategy for achieving a high level of heterodimer purity. And robust operation range of anion exchange chromatography steps for homodimer removal was also developed by leveraging the design of experiments. [ABSTRACT FROM AUTHOR]

[Display omitted] • A review of the literature on the analysis of pesticide residues in processed foods is presented. • Chromatographic methodologies coupled to Mass Spectrometry have been the most applied. • Advances in sample preparation, including the QuEChERS method, were presented. • Control of residues in fruit juices has been reported. • Legislation needs to cover a greater number of processed products of plant origin. In recent years, the number of publications related to the control of pesticides in food has been increasing, due to the risks associated with the intensive use of pesticides and the requirements of the legislations. This study aims to carry out a bibliographic review of research involving sample preparation and analysis of pesticides in processed foods of plant origin using efficient and modern methodologies for identifying and quantifying pesticide residues. This paper describes the studies related to food security and quality of processed products using chromatographic analysis related to Mass Spectrometry, modern multiresidue methods and the investigation of toxic residues in fruit juices. This study may assist the scientific community on the main advances in techniques for controlling the levels of residues in juices. The data emphasizes the importance of continuous monitoring of the processed product chain and seeks to encourage an increase in the scope of legislations. [ABSTRACT FROM AUTHOR]

• The framework provides sensitivity analyses and optimization on multiple indicators. • The framework can simulate platforms with different media and operating modes. • The simulation methodology incorporates multiple commercial software packages. • In our case study, membrane chromatography offers shorter process times than resin. • Disposable membrane platforms are economically feasible at case study conditions. We developed a computational framework that integrates commercial software components to perform customizable technoeconomic feasibility analyses. The use of multiple software packages overcomes the shortcomings of each to provide a detailed simulation that can be used for sensitivity analyses and optimizations. In this paper, the framework was used to evaluate the performance of monoclonal antibody capture processes. To this end, the simulation framework incorporated dynamic models for the affinity chromatography step that were validated with experimental breakthrough curves. The results were integrated with an Intelligen SuperPro Designer process simulation for the evaluation of key performance indicators of the operations. As proof of concept, the framework was used to perform a sensitivity analysis and optimization for a case study in which we sought to compare membrane and resin chromatography for disposable and reusable batch capture platforms. Two membranes and one resin were selected for the capture media, which yielded six process alternatives to compare. The objective functions were set to be cost of goods, process time, and buffer utilization. The results of the optimization of these process alternatives were a set of operating conditions that display tradeoffs between competing objectives. From this application exercise, we conclude that the framework can handle multiple variables and objectives, and it is adaptable to platforms with different chromatography media and operating modes. Additionally, the framework is capable of providing ad hoc analyses for decision making in a specific production context. [ABSTRACT FROM AUTHOR]

• Nanoemulsion sample matrix by cold dilution of microemulsion with water was developed. • Sample matrix for the signal amplification of hydrophobic compounds was employed. • The mechanism of signal amplification for hydrophobic compounds was described. • Sensitivity enhancement factor for vitamin K 2 -MK7 in NE matrix was determined. In this paper, an oil-in-water (O/W) nanoemulsion (NE) prepared by water cold dilution of an O/W microemulsion (ME) was introduced as a sample matrix in microemulsion electrokinetic capillary chromatography (MEEKC) for the highly hydrophobic compounds analysis. Several model compounds with log P O/W values in the 4.1–10.9 range, from different chemical groups, including retinol, α-tocopherol, cholecalciferol, phylloquinone, menaquinone-7, dichlorodiphenyltrichloroethane, ivermectin have been tested. As a proof of the concept of NE formation, a dynamic light scattering technique was employed to determine the size distribution profile of NE particles. Moreover, due to relatively low conductivity of the NE matrix (50–100 times lower in comparison to the separation buffer) and a negative electric charge provided to hydrophobic compounds through NE dispersed phase, NE matrices have been combined with preconcentration techniques based on electrokinetic dosing, namely field amplified sample injection (FASI) and pressure assisted electrokinetic injection (PAEKI). The detection limits for vitamin K 1 and K 2 -MK7 in the NE matrix in combination with FASI (NE–MEEKC–FASI) as well as PAEKI (NE–MEEKC–PAEKI) were up to 42.9 and 12.1 ng mL−1, respectively. In comparison to standard hydrodynamic injection for microemulsion sample matrix NE–MEEKC–PAEKI grant 45-fold improvement in signal sensitivity. The study presents an innovative approach, as it enables the use of preconcentration techniques for highly hydrophobic compounds (log P O/W > 4), which was not previously possible for implementation in the electromigration techniques. Likewise, the use of organic solvents has been reduced by using ME as a solvent for stock solutions and diluting with water prior to the analysis. The application to real samples was investigated using a dietary supplement containing vitamin K 2 -MK7 obtained from the fermentation product of soybeans. [ABSTRACT FROM AUTHOR]

• Enatioseparation of some agrochemicals using i-ADMPC as chiral selector. • Comparative study: nano-LC and CEC applied to enantiomers separation. • Higher efficiencies were obtained in CEC than in nano-LC. In this paper enantiomers of selected chiral agrochemicals representing various structural classes were separated by using nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) employing a capillary column packed with silica particles containing immobilized amylose tris(3‑chloro-5-methylphenylcarbamate) (i-ADMPC) as a chiral selector (CS). Special attention was paid to peak dispersion in nano-LC and CEC instruments used in order to make comparison between these two techniques more reliable. Enantioseparations were studied utilizing methanol (MeOH) or acetonitrile-water (ACN H 2 O), both containing 5 mM of ammonium acetate as the mobile phases (MPs). The tested chiral stationary phase (CSP), containing 20% (w/w) of the neutral CS onto native silica, allowed the generation of sufficiently strong electroosmotic flow (EOF) to observe separation of enantiomers of studied agrochemicals in a reasonable time also in CEC mode. Modestly higher efficiencies and enantioresolutions were obtained in CEC than in nano-LC. Just a moderate preference of CEC over nano-LC in this particular study can be explained with a significant mass transfer resistance through the CSP that is caused due to high content of the CS in CSP. [ABSTRACT FROM AUTHOR]

• A new SMB system to separate p -xylene and m -xylene was established. • Stationary phase was MIL-53(Fe) and mobile phase was petroleum ether-dichloromethane. • SMB was operated at ambient temperature. • 4 chromatographic columns in mode of 2–1–1 worked in a cyclic steady state. The separation of p -xylene (PX) and m -xylene (MX) isomers with near boiling points is a worldwide problem. The metal-organic framework material is an ideal stationary phase for chromatographic separation because of its high porosity, homogeneous pore diameter and good chemical stability. In this paper, a simulated moving bed (SMB) chromatography system with MIL-53(Fe) as the stationary phase and petroleum ether-dichloromethane as the mobile phase was designed to separate PX and MX at ambient temperature. Firstly, according to the elution curves of a single column, nonlinear competitive Langmuir adsorption isotherm equation was confirmed by equilibrium dispersive chromatography model. Then, the SMB separation zone was determined based on triangle theory, and the SMB operating conditions were optimized. Finally, the purity, recovery and productivity of PX reached 100.0%, 99.1% and 93.1 g/L/h, respectively; the purity, recovery and productivity of MX reached 96.4%, 100.0% and 23.5 g/L/h, respectively; the solvent consumption was 0.42 L/g. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-pyrolysis of wood and plastic was studied by Py-GC/MS. • Plastics promote secondary pyrolysis of holocellulose and lignin depolymerization. • Biomass hinders depolymerization of polyethylene, favors pyrolysis of polystyrene. • Analytical pyrolysis data used to estimate elemental composition of pyrolysates. • Most significant synergistic effects observed in mixtures with 30% plastic. This paper presents a study on the pyrolytic behavior of mixtures of lignocellulosic biomass with hydrocarbon plastics using analytical pyrolysis-GC/MS. Semi-quantitative analysis using chromatographic peak areas was used to investigate the composition of the pyrolysis oils and to highlight the occurrence of synergistic effects. A new method is also proposed to estimate the elemental composition of the pyrolysis oil based on the peak areas and brute formulas of the pyrolysis products. The results indicate that synergistic effects during co-pyrolysis favor secondary pyrolysis of holocellulose and polystyrene oligomers, and hinder radical chain-scission of polyethylene chains. H/C and O/C values of the pyrolysis oils were improved by the addition of plastic, indicating a decrease in the content of oxygenated pyrolysis products. The best performances were observed for the mixture containing 70% fir wood and 30% polyethylene, in which synergistic effects led to both an increase of H/C and a decrease of O/C. [ABSTRACT FROM AUTHOR]

• A new tool for the enantioseparations of carboranes in the reversed-phase mode • Polysaccharide-based chiral selectors as an alternative to the beta-cyclodextrins • The first enantioseparation of cobalt bis(dicarbollide) anions with unrestrained geometry The aspect of the different spatial arrangement of anionic cobalt bis(dicarbollides) and dicarba- nido -undecaboranes remains grossly overlooked despite increased scientific interest. Regarding their growing potential, which does not limit only to medicinal chemistry, suitable enantioseparation methods are needed. The presented paper explores the possibilities of chiral separations of anionic cobalt bis(dicarbollide) and dicarba-7,8- nido -undecaborane derivatives on four polysaccharide-based columns under reversed-phase conditions. The chromatographic behavior of anionic derivatives was evaluated and compared with that of zwitterionic clusters. The isocratic procedure for HPLC method development was suggested. The main parameters for the optimization of separations were described. Successful chiral separations were critically compared to previously reported results in normal phase and polar-organic mode. Reversed-phase separations are superior in resolution, lower consumption of organic solvents, and flexibility during the method development. Moreover, the first chiral discrimination of some hydroxyalkyl derivatives of anionic cobalt bis(dicarbollides) is reported. The outcomes of this work may be used for method development in any area, where the chirality of these interesting molecules is of concern. [ABSTRACT FROM AUTHOR]

• Thermal oxidation of erucamide occurs in polyolefins during processing and improper storage. • The oxidation of erucamide results in several primary and secondary degradation products including off-flavor compounds. • About 16 primary and secondary oxidation products of erucamide were identified and characterized by HRMS. • This research paper describes plausible mechanisms for erucamide degradation compounds formation. Polyolefins use erucamide as one of their primary slip agents. The degradation of erucamide can occur during polymer processing and long-term storage, leading to the formation of numerous oxidation products. Erucamide degradation produces compounds that adversely affect the odor and color properties of polyolefins. The article describes the comprehensive characterization of erucamide degradation products formed in three different lots of low-density polyethylene (LDPE) using thermal desorption-gas chromatography mass spectrometry (TD-GC/MS) and liquid chromatography-high resolution mass spectrometry (LC HRMS) techniques. More than 20 volatile and non-volatile degradation compounds of erucamide were identified in LDPE. The structures of non-volatile degradants were predicted using both the molecular formula generated and MS/MS fragmentation data obtained by LC HRMS. The non-volatile and volatile degradation compounds formed in odorous LDPE resins were compared with that of the reference sample of LDPE having no odor. Further, the plausible mechanism of formation of volatile and non-volatile degradation compounds of erucamide is proposed. [ABSTRACT FROM AUTHOR]

Many studies reported the chemical composition and the biological activities of Pinus Essential oils (EOs). A few of them were investigated for their antibacterial activity against strains responsible for otitis. The present paper investigated the variation of the chemical composition and the antibacterial activity of the EOs of five Tunisian Pinus species and of their combinations against six bacterial strains responsible for otitis. The EOs' yields varied from 0.3 ± 0.1% for P. pinea to 1.8 ± 0.4% for P. halepensis. Their chromatographic analyses by GC and GC-MS identified 139 components varying according to the species. The main components were β -pinene followed by trans -caryophyllene, germacrene D, α -pinene, β -myrcene, palustradiene, abieta-7,13-triene, levopimaradiene, thunbergol, and caryophyllene oxide. Four chemical groups were identified basing on the PCA and the HCA of the 25major's components of the studied EOs. However, three subgroups were identified within the antibacterial-based PCA and HCA analyses. The highest antibacterial activity was observed with the blends of oils extracted from P. halepensis and P. canariensis and mixture of oils extracted from P. brutia and P. canariensis. These EOs blends may constitute promising antibiotic alternatives for the treatment of the otitis media. [Display omitted] • The PCA and the HCA analysis of studied EOs identified four chemotypes • The antibacterial activities is controlled by the EOs chemical composition • The antibacterial activity could be enhanced by mixing several Pinus EOs [ABSTRACT FROM AUTHOR]

• Column/solvent screening strategy for method development of peptides is described. • Use of NH 4 PF 6 and CH 3 SO 3 H as mobile phase additives is described. • TFA was demonstrated not always to be the preferred mobile phase additive. The paper describes a simple and rapid reversed-phase UHPLC method development screening strategy for the purity determination of peptide-based pharmaceuticals. The protocol utilises five disparate column and six volatile or non-volatile mobile phases (i.e., 30 combinations). The method development strategy has been demonstrated to be highly effective in identifying conditions which generate complementary selectivity and good peak shape. Columns with varying degrees of charge (positive and negative), in addition to their differing hydrophobic character, were used in combination with mobile phases within the pH range of 2.3 to 5.1. The novel ion-pair / chaotropic reagent ammonium hexafluorophosphate at pH 2.3 was shown to be an extremely useful mobile phase additive in that it produced excellent complementary separation and good peak shape. Methanesulfonic acid was demonstrated to be a good alternative to the ubiquitously employed trifluoroacetic acid which failed to generate optimum separation for the peptides investigated highlighting the importance of screening disparate mobile phase additives. Both ammonium hexafluorophosphate and methanesulfonic acid were shown not to adversely affect the stability of C18 columns or demonstrated any irreversible adsorption / memory effects. No pH hysteresis effects were demonstrated with any of the stationary phases on mobile phase pH cycling. No major problems have been observed with the novel mobile phase additives ammonium hexafluorophosphate and methanesulfonic acid, however, it is recommended that they be used with caution until long-term routine use has been established. [ABSTRACT FROM AUTHOR]

• Efficient development of robust flow-through CEX steps for ADC products. • mAb purification data can be used for purification of their respective conjugates. • Flow-through CEX removes aggregate species from ADCs. 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. [ABSTRACT FROM AUTHOR]

Analytical method has been developed to determine volatile organic compounds (VOCs) in reverse osmosis (RO) membrane using headspace-gas chromatography/mass spectrometry (HS-GC/MS). The operating parameters, including incubation temperature, incubation time and the choice of matrix modifier, were investigated. The existence of matrix effect was evaluated and the VOC-free RO membrane was selected as the best material for developing matrix-matched calibration curve. At these optimized operating conditions, the established method was found to perform well — giving good linearity (r > 0.996), allowing for consistent repeatability (<9.5%), making possible high levels of VOC recoveries (84.7%–123%) and satisfactory detection limits (3.44–748 μg/kg). The method was applied to determining thirty-seven common VOCs for RO membrane. Toluene and N , N -dimethylformamide were the most abundant VOCs in measured samples, with average contents of 90 087 μg/kg and 249 957 μg/kg respectively. In addition, a range of other common compounds, including acetone, dichloromethane, hexane, chloroform, 1,2-dichloroethane, benzene, chlorobenzene, ethylbenzene, xylene, and styrene, were also found with content between N.D.—112 419 μg/kg in detection rate between 40%–100%. The analysis of VOC distribution provides further substantial evidence that the solvents used during the production of the RO membrane frequently are the main source of VOCs in commercial RO membrane. Our experiments proved that, of these VOCs, four compounds, dichloromethane, chloroform, 1,2-dichloroethane, and toluene, were hardly removed by pre-washing. The relationship between the content of VOCs in RO membrane and their corresponding concentration in filtrated water shows a highly positive correlation and the safety limit values for these four compounds are evaluated as 2.6 × 102–3.8 × 105 μg/kg, but more accurate and completed guideline values should be formulated to guarantee the RO membrane quality. • Headspace technology was employed as an effective pretreatment method for VOC determination in RO membranes. • The results obtained via matrix-matched calibration was easy, accurate and cost-effective. • Source and potential risk assessment of VOCs in RO membranes were discussed in this paper. [ABSTRACT FROM AUTHOR]

α-Cedrol, a monoterpene alcohol, is an industrially valuable compound used in different productions due to its diverse pharmacological and therapeutic effects. This paper reports the isolation of this compound from essential oil of Platycladus orientalis (Thuja orientalis) leaves using high performance countercurrent chromatography (HPCCC) for the first time. Two different methodologies were developed with hexane-ethyl acetate-methanol-water (HEMWat) solvent systems used in reversed phase linear gradient elution mode. In the first method, the gradient from HEMWat 17 (1/1/1/1) to 27 (19/1/19/1) solvent systems allowed isolation of 29.8 mg of high purity α-cedrol crystals with 86.6% recovery from 50 mg/mL sample solution as well as isolation of other components. In the 2nd method gradient from HEMWat 23 (4/1/4/1) and 27 (19/1/19/1) solvent systems of narrower polarity range resulted in doubling sample concentration to 100 mg/mL. Also the 2nd method reduced the elution time of α-cedrol to just 70 min with comparatively higher amount (65.72 mg) and percent recovery (94.58%) as compared to previous run. • α-Cedrol is a major constituent of hydrodistilled essential oil of Platycladus orientalis leaves. • α-Cedrol can be isolated by Countercurrent Chromatography (CCC). • HEMWat. 17, 27 or HEMWat. 23, 27 solvent systems are useful for α-Cedrol isolation. [ABSTRACT FROM AUTHOR]

• Recombinant adeno-associated virus (rAAV)-mediated gene therapy is a fast-evolving. • High throughput (HTP) chromatography significantly speed up AAV process development. • HTP chromatography using resin slurry plate and mini-column for AAV purification. • Demonstrated performance comparability between HTP and bench-scale chromatography. Recombinant adeno-associated virus (AAV) has been broadly used as a delivery tool for gene therapy applications. The development of a robust purification process is essential for delivering high purity and quality AAV products to clinic. The short clinical timelines and material limitations of early-stage development pose unique challenges to developing robust and scalable downstream purification processes. One approach to overcome these limitations is to leverage high throughput (HTP) strategies and automation technologies for purification process development, an approach that is well established in protein biologics and other areas. However, due to the unique challenges related to viral vector purification, implementing HTP approaches for gene therapy process development has not been explored extensively. In this paper, we established a HTP chromatography platform and demonstrated its capability to facilitate gene therapy purification process development using both mini-columns and self-packed resin plates. The end-to-end development workflow for AAV HTP purification is detailed in this work with the expectation of serving as an introductory for the AAV purification development field. Comparable process performance was confirmed between a bench-scale chromatography process and an HTP chromatography format. Slightly lower recovery was observed using the HTP format (62% vs 75%), as well as %full capsid enrichment (71% vs. 82%). Comparable impurity clearance capability was demonstrated between the two different systems as well. It was concluded that the established HTP chromatography formats can serve as a surrogate to bench-scale chromatography development to reduce material needs and development timelines for AAV purification development. [ABSTRACT FROM AUTHOR]

Protein A affinity chromatography, which is the standard method for purifying monoclonal antibodies (mAbs) is expensive and involves elution at acidic pH, which could degrade the mAb. Moreover, it cannot be used to fractionate charge variants or to remove mAb aggregates. In this study, we examine the purification of Trastuzumab by cation-exchange z2 laterally-fed membrane chromatography (or z2LFMC). It has been shown that z2LFMC is suitable for carrying out high-speed, high-resolution protein purification. The results discussed in this paper demonstrate that the purity of Trastuzumab obtained by the z2LFMC process was comparable to that obtained by protein A chromatography (i.e., >95% with both methods), while the recovery was significantly greater with z2LFMC (90.4% as opposed to 81.7%). Also, the z2LFMC process was faster, did not require acidic pH conditions for elution, and the mAb was eluted in 2.24 bed volumes as opposed to 2.74 bed volumes with protein A chromatography. The mAb productivity obtained with the z2LFMC process was more than 3 times higher than that with the column-based purification process. The z2LFMC device is significantly cheaper than its equivalent protein A affinity column, and earlier studies have shown it to be suitable for separating mAb charge variants and aggregates. Therefore, the z2LFMC process could be evaluated as a cheaper and more efficient alternative to protein A affinity chromatography. • An economic and efficient alternative to protein A affinity chromatography. • Monoclonal antibody purified under mild processing conditions. • Faster separation than other methods including protein A affinity chromatography. • Comparable purity to that obtained by protein A affinity chromatography. • Higher recovery than Protein A affinity chromatography. [ABSTRACT FROM AUTHOR]

• PCA cannot handle GC–MS data well since it does not account for mis-aligned peaks. • Gaussian dynamic time warping (DTW) kernel is proposed to align GC–MS data. • The proposed method reveals better clusters of propolis from 8 regions in the US. • The proposed DTW-KPCA of GC–MS data is more effective than classic PCA and Kernel PCA. The chemometric analysis of chromatographic data is commonly used for discriminating bee propolis based on their geographical origin. Traditional machine learning methods for this purpose include principal component analysis and hierarchical clustering. When viewed as a time-series, the key discriminatory features in chromatographic data are the peaks, which should have similar location patterns for the propolis of the same origin. However, the peaks between same-origin samples are not always exactly aligned. Without proper alignment, samples from the same origin may be perceived by the clustering method to be very different. In this paper, we propose a novel dynamic time warping kernel principal component analysis (DTW-KPCA) method for the chemometric discrimination of propolis. The proposed method uses a Gaussian dynamic time warping kernel to measure the similarity between chromatographic time-series which incorporates time-series alignment. Results show a better clustering of propolis samples compared to the currently used methods, as measured by the silhouette coefficient. Hence, the proposed method enables a more reliable clustering as to the origin of propolis samples. [ABSTRACT FROM AUTHOR]