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The kinetics of organic reactions of different types in microvolumes (droplets, thin films, and sealed tubes) show effects of gas/solution interfacial area, reaction molecularity and solvent polarity. Partial solvation at the gas/solution interface is a major contributor to the 104 -fold reaction acceleration seen in bimolecular but not unimolecular reactions in microdroplets. Reaction acceleration can be used to manipulate selectivity by solvent choice.

In this study, alkali/acid treatment and ion exchange post-synthesis modification methods to modify the pore diameter and structure of molecular sieve 13X (MS13X) were applied to obtain products, which could then be implemented to improve the enrichment recovery of hopanoids in petroleum. The modification products were analyzed by SEM with EDS, XRD and nitrogen physisorption. The results indicated that the product which had been prepared in the oxalic acid ethanol solution formed some mesopores, and also retained the initial framework of crystal. It was revealed that this product was able to remarkably increase the recovery rate of hopanoids in petroleum without leading to a significant isotope fractionation phenomenon. It is thus shown that this modification method of non-aqueous oxalic acid solution for MS13X can be used as an effective pretreatment tool in the application of compound-specific isotope analysis of hopanes with low concentration.

Mass spectrometry (MS) was considered as the most informative technique for components identification and has been widely adopted in plant sciences. However, spatial distribution of compounds in plant, which is vital for the exploration of plant physiological mechanism, is missed in MS analysis. Recent years mass spectrometry imaging has brought great breakthrough in plant analysis, because it can determine both the molecular compositions and spatial distributions, which is conducive to understand functions and regulation pathways of specific components in plants. Mass spectrometry imaging analysis of plant tissue is toward high sensitivity, high spatial resolution, and even single cell analysis. Despite of many challenges and technical barriers, such as difficulties of sample pretreatment caused by morphological diversity of plant tissues, obstacles for high spatial resolution imaging, and so on, lots of researches have contribute to remarkable progresses, including improvement in tissue preparation, matrix innovation, and ionization mode development. This review focuses on the advances of mass spectrometry imaging analysis of plant in the last 5 years, including commonly used ionization techniques, technical advances, and recent applications of mass spectrometry imaging in plants. This article is protected by copyright. All rights reserved.

Aristolochic acid analogues (AAAs), naturally existing in herbal Aristolochia and Asarum genera, were once widely used in traditional pharmacopeias because of their anti-inflammatory properties, but lately they were identified as potential nephrotoxins and mutagens. A method for rapid characterization of AAAs in serum was developed using ion mobility spectrometry coupled with mass spectrometry (IMS-MS). Five AAAs, containing four aristolochic acids and one aristolactam, were separated and identified within milliseconds. AAAs were separated in gas phase based on the difference of their ion mobility (K0), and then identified based on their K0 values, m/z, and product ions from MS/MS. Quantitative analysis of AAAs was performed using an internal standard with a satisfactory sensitivity. Limits of detection (signal-to-noise = 3) and quantification (signal-to-noise = 10) were 1–5 ng/mL and 3–8 ng/mL, respectively. The method was validated and successfully applied to the pharmacokinetics study of AAAs in rats, offering a promising way for fast screening and evaluation of AAAs in biological samples.

Metabolites in the xylem experience several migration and transformation processes during tree growth. Their composition and distributions can reflect the environment that the wood lived through. Herein, a matrix-assisted laser desorption/ionization mass spectrometry imaging method was developed to investigate the migration and transformation of metabolites in the xylem during heartwood formation and after mechanical injury. The thickness of the wood slice, the type of matrix and its manner of deposition were optimized to improve ionization response and spatial resolution. The mass difference correlation (MDC) data processing method was proposed to improve the efficiency of compound identification, in which the compounds were classified by their molecular weight. The compound species was identified by results calculated using MDC and the experimental results from MS/MS. The directly identified metabolites, whose type and number were found to be quite different between sapwood and heartwood, demonstrated the transformation and migration of metabolites from sapwood to heartwood. Additionally, two kinds of resins produced from different positions were identified by MSI simultaneously, even though their heterogeneous distribution was not visible in optical images. The origin and type of the two resins were deduced from the identified compounds and their molecular distribution. This work provides a method to directly reveal metabolite migration and transformation mechanisms in xylem during wood growth.

Mass spectrometry imaging (MSI) is a promising chemical imaging method. Among various endogenous molecules, mapping the concentration and the spatial distribution of specific compounds in the coffee bean tissue is of tremendous significance in its function research, as these compounds are critical to grading coffee beans at the molecular level, determining the geographical origin, and optimizing storage conditions of coffee beans. In this paper, we established an atmospheric pressure (AP) matrix-assisted laser desorption/ionization (MALDI) MSI method for the microscopic distribution analysis of endogenous molecules, for example, sucrose, caffeine, and caffeoylquinic acid, in the coffee bean endosperm. Experiments were done on the differences between coffee beans from eight countries. Principal component analysis (PCA) was performed using IMAGEREVEAL software. The results showed that the chemical composition and relative content of coffee beans from different origins are different. Our work provides a detection method that may be used for coffee bean quality identification, efficient use, product traceability, and product counterfeiting.

A novel online two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography-triple-quadrupole mass spectrometry (2D SFC/RPLC-QQQ MS) method based on a vacuum solvent evaporation interface was developed for lipid profiling in human plasma, in which lipid classes were separated by the first-dimension SFC and different lipid molecular species were further separated by the second-dimension RPLC. All separation condition parameters were carefully optimized, and their influence on the chromatographic behavior of lipids is discussed. Finally, the recoveries of 11 lipid standards were all more than 88% for the interface. Besides, the limit of detection for these lipid standards was on the order of nanograms per milliliter, and the relative standard deviations of the peak area and retention time ranged from 1.54% to 19.85% and from 0.00% to 0.10%, respectively. The final 2D SFC/RPLC-QQQ MS method allowed the identification of 370 endogenous lipid species from ten lipid classes, including diacylglycerol, triacylglycerol, ceramide, glucosylceramide, galactosylceramide, lactosylceramide, sphingomyelin, acylcarnitine, phosphatidylcholine, and lysophosphatidylethanolamine, in human plasma within 38 min, which was used for screening potential lipid biomarkers in breast cancer. The 2D SFC/RPLC-QQQ MS method is a potentially useful tool for in-depth studies focused on complex lipid metabolism and biomarker discovery. Graphical Abstract.

Lentiviral vectors have been proven to be a powerful tool in gene therapies that includes the ability to perform long-term gene editing in both dividing and non-dividing cells. In order to meet the rising demand for clinical-grade lentiviral vectors for future clinical trials and requirements by regulatory agencies, new methods and technologies were developed, including the rapid optimization of production and purification processes. However, gaps still exist in achieving ideal yields and recovery rates in large-scale manufacturing process steps. The downstream purification process is a critical step required to obtain a sufficient quantity and high-quality lentiviral vectors products, which is challenged by the low stability of the lentiviral vector particles and large production volumes associated with the manufacturing process. This review summarizes the most recent and promising technologies and enhancements used in the large-scale purification process step of lentiviral vector manufacturing and aims to provide a significant contribution towards the achievement of providing sufficient quantity and quality of lentiviral vectors in scalable processes.

Lung cancer is the leading cause of cancer mortality, and early detection is key to improving survival. However, there are no reliable blood-based tests currently available for early-stage lung cancer diagnosis. Here, we performed single-cell RNA sequencing of different early-stage lung cancers and found that lipid metabolism was broadly dysregulated in different cell types, with glycerophospholipid metabolism as the most altered lipid metabolism–related pathway. Untargeted lipidomics was carried out in an exploratory cohort of 311 participants. Through support vector machine algorithm-based and mass spectrum–based feature selection, we identified nine lipids (lysophosphatidylcholines 16:0, 18:0, and 20:4; phosphatidylcholines 16:0–18:1, 16:0–18:2, 18:0–18:1, 18:0–18:2, and 16:0–22:6; and triglycerides 16:0–18:1–18:1) as the features most important for early-stage cancer detection. Using these nine features, we developed a liquid chromatography–mass spectrometry (MS)–based targeted assay using multiple reaction monitoring. This target assay achieved 100.00% specificity on an independent validation cohort. In a hospital-based lung cancer screening cohort of 1036 participants examined by low-dose computed tomography and a prospective clinical cohort containing 109 participants, the assay reached more than 90.00% sensitivity and 92.00% specificity. Accordingly, matrix-assisted laser desorption/ionization MS imaging confirmed that the selected lipids were differentially expressed in early-stage lung cancer tissues in situ. This method, designated as Lung Cancer Artificial Intelligence Detector, may be useful for early detection of lung cancer or large-scale screening of high-risk populations for cancer prevention.

To enhance the characterization of wood extractives at molecular level, a detailed ultrahigh-resolution mass spectrometry (UHRMS)-based analytical methodology was developed in this work. The analytical strategies, including selection of compatible solvent for extraction, evaluation of ionization solvent for effective electrospray ionization, and multi-dimensional data analysis, were established to ensure a comprehensive characterization of complex compositions in wood extractives. Extraction capability of seven solvents with varied polarities was examined by a standard reference material of hardwood biomass and evaluated based on thousands of compounds which were much more than those discovered before. With a variety of data-processing approaches, including compound type distribution, double bond equivalent versus carbon number plot, and van Krevelen diagram, the chemodiversity of the extractives was fully explored from different perspectives. This work greatly expanded the compound library of wood extractives and could also provide guidance for the integrated composition analysis of other biomass materials.

Description, The machine learning–aided serum lipidomics approach could be used to help early diagnosis of patients with PDAC., Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers, characterized by rapid progression, metastasis, and difficulty in diagnosis. However, there are no effective liquid-based testing methods available for PDAC detection. Here we introduce a minimally invasive approach that uses machine learning (ML) and lipidomics to detect PDAC. Through greedy algorithm and mass spectrum feature selection, we optimized 17 characteristic metabolites as detection features and developed a liquid chromatography-mass spectrometry-based targeted assay. In this study, 1033 patients with PDAC at various stages were examined. This approach has achieved 86.74% accuracy with an area under curve (AUC) of 0.9351 in the large external validation cohort and 85.00% accuracy with 0.9389 AUC in the prospective clinical cohort. Accordingly, single-cell sequencing, proteomics, and mass spectrometry imaging were applied and revealed notable alterations of selected lipids in PDAC tissues. We propose that the ML-aided lipidomics approach be used for early detection of PDAC.

Background Atherosclerosis preferentially develops in regions of disturbed flow (DF). Emerging evidence indicates that yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), which are both effectors of the Hippo pathway, sense different blood flow patterns and regulate atherosclerotic lesions. We previously found that methotrexate (MTX) reduces in-stent neoatherosclerosis, decreases the plaque burden, and has an effect on local fluid shear stress. Here, we investigated the atheroprotective effect of MTX under DF and the mechanisms underlying these properties. Methods Human umbilical vein endothelial cells (HUVECs) were subjected to biomechanical stretch using a parallel-plate flow system and treated with or without MTX at therapeutically relevant concentrations. Additionally, an extravascular device was used to induce DF in the left common carotid artery of C57BL/6 mice, followed by treatment with MTX or 0.9% saline. The artery was then assessed histopathologically after 4 weeks on a Western diet. Results We observed that MTX significantly inhibited DF-induced endothelial YAP/TAZ activation. Furthermore, it markedly decreased pro-inflammatory factor secretion and monocyte adhesion in HUVECs but had no effect on apoptosis. Mechanistically, AMPKa1 depletion attenuated these effects of MTX. Accordingly, MTX decreased DF-induced plaque formation, which was accompanied by YAP/TAZ downregulation in vivo. Conclusions Taken together, we conclude that MTX exerts protective effects via the AMP-dependent kinase (AMPK)-YAP/TAZ pathway. These results provide a basis for the prevention and treatment of atherosclerosis via the inhibition of YAP/TAZ.

Background: Despite intensive investigation, effective therapeutic procedures for myocardial I/R injury are still in demand. Objective: To explore the effect of adeno-associated virus 9 (AAV9)-mediated small interfering RNA targeting TLR4 in the treatment of myocardial ischemia and reperfusion (I/R) injury and its influence on the NF-κB and MAPK signaling pathways. Methods: Rats were divided into 3 groups, namely, the sham, AAV9-siRNA control, and AAV9-TLR4 siRNA groups. siRNA solution or normal saline was injected through the tail vain. The rat myocardial I/R injury model was then established. HE staining and TUNEL staining were applied to compare the pathological changes in cardiomyocytes in the three groups. Immunohistochemical staining and western blotting were utilized to detect TLR4 expression under siRNA interference. Serum inflammatory factor (IL-1β, TNF-α) expression was determined by an ELISA commercial kit. Key proteins in the MAPK (p38, JNK 1/2) and NF-κB (p65) signaling pathways were determined to identify the TLR4 siRNA functional mechanism. Results: Fluorescence microscopic images of the myocardium indicated that AAV9- mediated siRNA was efficiently transfected into the myocardium, and the infarcted size after I/R injury was decreased by AAV9-TLR4 siRNA when compared with negative control rats (P Conclusion: AAV9-TLR4 siRNA has a positive effect on myocardial I/R injury by inhibiting the MAPK and NF-κB signaling pathways and can be used as a potential therapeutic method for myocardial I/R injury.

In this work, a novel Fe3O4@Cu3(btc)2-embedded polymerized high internal phase emulsion (Fe3O4@HKUST-1-polyHIPE) monolithic cake was synthesized, characterized and used as an adsorbent in the magnetic stir cake sorptive extraction (MSCSE) and determination of tetracycline antibiotics (TCs) in food samples by a combination of with high-performance liquid chromatography–fluorescence detection (HPLC-FLD). The prepared Fe3O4@HKUST-1-polyHIPE monolithic composites displayed a strong extraction ability and high column capacity due to enhanced interactions such as π–π interactions, hydrogen bonding, and electrostatic interactions. The extraction and desorption conditions were evaluated, and the calibration curves of four spiked TCs were linear (R2 ≥ 0.9991) in the range from 20 to 800 ng mL−1 for milk and egg samples, and 20 to 800 ng g−1 for chicken muscle and kidney samples. The limits of detection and the limits of quantification of the four TCs by using the proposed MSCSE-HPLC-FLD method were in the range of 1.9–4.6 and 5.5–13.9 ng mL−1 for milk and egg samples, and 1.8–3.7 and 5.3–13.0 ng g−1 for chicken muscle and kidney samples, respectively. The recoveries of the target TCs from spiked food samples were in the range from 86.6 to 110.7% with relative standard deviations lower than 7.0%. The proposed method was successfully applied for the determination of these four TCs in milk, egg, chicken muscle, and kidney samples.

In situ analysis of glycans is of great significance since they mediate a range of biological activities. Aberrant changes of glycosylation are closely related to cancer onset and progression. In this work, bifunctional laser cleavable mass probes (LCMPs) were developed for in situ glycan detection from both cells and tissues using laser desorption ionization mass spectrometry (LDI-MS). Specific recognition of glycans was achieved by lectins, and inherent signal amplification was achieved by the conversion of the detection of glycans to that of mass tags which overcame the low ionization efficiency and complicated mass spectra of glycans. Multiplexed glycan profiling was easy to implement due to the simple and generic synthetic route to LCMPs and serial alternative mass tags, which offers high sensitivity, low interference and in situ detection of glycans. Moreover, as an excellent inherent matrix, LCMPs facilitated direct glycan detection from the cell surface and tissue imaging using LDI-MS. Intrinsic and fine glycan distribution in human cancer and paracancerous tissues was strictly demonstrated by MS imaging to explore the correlation between glycosylation and various cancers. This approach presented a versatile LDI-MS based platform for fast and in situ multiplexed glycan engineering, thus providing a new perspective in glycobiology and clinical diagnosis.

The structural information and spatial distribution of molecules in biological tissues are closely related to the potential molecular mechanisms of disease origin, transfer, and classification. Ambient ionization mass spectrometry imaging is an effective tool that provides molecular images while describing in situ information of biomolecules in complex samples, in which ionization occurs at atmospheric pressure with the samples being analyzed in the native state. Ambient ionization mass spectrometry imaging can directly analyze tissue samples at a fairly high resolution to obtain molecules in situ information on the tissue surface to identify pathological features associated with a disease, resulting in the wide applications in pharmacy, food science, botanical research, and especially clinical research. Herein, novel ambient ionization techniques, such as techniques based on spray and solid-liquid extraction, techniques based on plasma desorption, techniques based on laser desorption ablation, and techniques based on acoustic desorption were introduced, and the data processing of ambient ionization mass spectrometry imaging was briefly reviewed. Besides, we also highlight recent applications of this imaging technology in clinical researches and discuss the challenges in this imaging technology and the perspectives on the future of the clinical research.

Stroke is a major cause of mortality and long-term disability worldwide. The study of biomarkers and pathogenesis is vital for early diagnosis and treatment of stroke. In the present study, a continuous-flow normal-phase/reversed-phase two-dimensional liquid chromatography-quadrupole time-of-flight mass spectrometry (NP/RP 2D LC-QToF/MS) method was employed to measure lipid species in human plasma, including healthy controls and lacunar infarction (LI) patients. As a result, 13 lipid species were demonstrated with significant difference between the two groups, and a "plasma biomarker model" including glucosylceramide (38:2), phosphatidylethanolamine (35:2), free fatty acid (16:1), and triacylglycerol (56:5) was finally established. This model was evaluated as an effective tool in that area under the receiver operating characteristic curve reached 1.000 in the discovery set and 0.947 in the validation set for diagnosing LI patients from healthy controls. Besides, the sensitivity and specificity of disease diagnosis in validation set were 93.3% and 96.6% at the best cutoff value, respectively. This study demonstrates the promising potential of NP/RP 2D LC-QToF/MS-based lipidomics approach in finding bio-markers for disease diagnosis and providing special insights into the metabolism of stroke induced by small vessel disease. Graphical abstract Flow-chart of the plasma biomarker model establishment through biomarker screening and validation.

Glycerolipid is a main component of membranes in oxygenic photosynthetic organisms. Up to now, the majority of publication in this area has focused on the physiological functions of glycerolipids and lipoprotein complexes in photosynthesis, but the study on the separation and identification of glycerolipids in thylakoid membrane in cyanobacteria is relatively rare. Here we report a new method to separate and identify five photosynthetic glycerolipid classes, including monoglucosyl diacylglycerol, monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol, in cyanobacteria Synechococcus sp. PCC 7002 by two-dimensional (normal- and reversed-phase) liquid chromatography online coupled to quadrupole time-of-flight mass spectrometry. Over twice as many lipid species were detected by our method compared to the previously reported methods. Ten new odd-chain fatty acid glycerolipids were discovered for the first time. Moreover, complete separation of isomers of monogalactosyl diacylglycerol and monoglucosyl diacylglycerol was achieved. According to the tandem mass spectrometry results, we found that the head group of monoglucosyl diacylglycerols was not as stable as that of monogalactosyl diacylglycerols, which might explain why the organism chose monogalactosyl diacylglycerols and digalactosyl diacylglycerols instead of monoglucosyl diacylglycerols as the main content of the photosynthetic membranes in the history of evolution. This work will benefit further research on the physiological function of glycerolipids.

Rationale With the amounts and types of new psychoactive substances (NPSs) increasing rapidly in recent years, an excellent high-throughput method for the analysis of these compounds is urgently needed. In this article, a rapid screening method and a quantitative analysis method for 11 NPSs are described and compared, respectively. Method A simple direct analysis in real time mass spectrometry (DART-MS) method was developed for the analysis of 11 NPSs including three categories of these substances present on the global market such as four cathinones, one phenylethylamine, and six synthetic cannabinoids. In order to analyze these compounds quantitatively with better accuracy and sensitivity, another rapid analytical method with a low limit of detection (LOD) was also developed using liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (LC/QTOFMS). Results The 11 NPSs could be determined within 0.5 min by DART-MS. Furthermore, they could also be separated and determined within 5 min by the LC/QTOFMS method. The two methods both showed good linearity with correlation coefficients (r(2) ) higher than 0.99. The LODs for all these target NPSs by DART-MS and LC/QTOFMS ranged from 5 to 40 ng mL(-1) and 0.1 to 1 ng mL(-1) , respectively. Confiscated samples, named as "music vanilla" and "bath salt", and 11 spiked samples were firstly screened by DART-MS and then determined by LC/QTOFMS. Conclusions The identification of NPSs in confiscated materials was successfully achieved, and the proposed analytical methodology could offer rapid screening and accurate analysis results. Copyright © 2016 John Wiley & Sons, Ltd.

A bifunctional monolith dip-it was fabricated and applied for improving the sensitivity of direct analysis in real time mass spectrometry (DART-MS). This monolith dip-it device was prepared by in situ polymerization of poly(BMA-EDMA-MAA) monolith in the glass capillary of dip-it. As a solid-phase microextraction (SPME) device, it showed strong affinity to four Sudan dyes through hydrophilic interaction and hydrogen bond interaction. As a sample loading device, it could be directly analyzed by DART-MS without organic solvent elution or laser desorption. As a result, this device is environmentally friendly, and used for fast analysis. Under optimized conditions, the limits of detection for four analytes were 5-10 ng mL(-1) and the linear ranges covered more than two orders of magnitude. Finally, the developed method has been applied for the analysis of chili powder and the recoveries for spiked analytes were in the range of 83.2% to 115.1% demonstrating that this device is an efficient sampler for DART-MS analysis and the proposed method could find more applications in different areas like food analysis.

In situ multiplexed detection and imaging of glycans is of great significance since they mediate a range of biological activities., In situ analysis of glycans is of great significance since they mediate a range of biological activities. Aberrant changes of glycosylation are closely related to cancer onset and progression. In this work, bifunctional laser cleavable mass probes (LCMPs) were developed for in situ glycan detection from both cells and tissues using laser desorption ionization mass spectrometry (LDI-MS). Specific recognition of glycans was achieved by lectins, and inherent signal amplification was achieved by the conversion of the detection of glycans to that of mass tags which overcame the low ionization efficiency and complicated mass spectra of glycans. Multiplexed glycan profiling was easy to implement due to the simple and generic synthetic route to LCMPs and serial alternative mass tags, which offers high sensitivity, low interference and in situ detection of glycans. Moreover, as an excellent inherent matrix, LCMPs facilitated direct glycan detection from the cell surface and tissue imaging using LDI-MS. Intrinsic and fine glycan distribution in human cancer and paracancerous tissues was strictly demonstrated by MS imaging to explore the correlation between glycosylation and various cancers. This approach presented a versatile LDI-MS based platform for fast and in situ multiplexed glycan engineering, thus providing a new perspective in glycobiology and clinical diagnosis.

The pursuit of high-throughput sample analysis from complex matrix demands development of multiple ionization techniques with complementary specialties. A versatile integrated ambient ionization source (iAmIS) platform is proposed in this work, based on the idea of integrating multiple functions, enhancing the efficiency of current ionization techniques, extending the applications, and decreasing the cost of the instrument. The design of the iAmIS platform combines flowing atmospheric pressure afterglow (FAPA) source/direct analysis in real time (DART), dielectric barrier discharge ionization (DBDI)/low-temperature plasma (LTP), desorption electrospray ionization (DESI), and laser desorption (LD) technique. All individual and combined ionization modes can be easily attained by modulating parameters. In particular, the FAPA/DART&DESI mode can realize the detection of polar and nonpolar compounds at the same time with two different ionization mechanisms: proton transfer and charge transfer. The introduction of LD contributes to the mass spectrometry imaging and the surface-assisted laser desorption (SALDI) under ambient condition. Compared with other individual or multi-mode ion source, the iAmIS platform provides the flexibility of choosing different ionization modes, broadens the scope of the analyte detection, and facilitates the analysis of complex samples. Graphical abstract ᅟ.

Rationale Owing to the widespread abuse of new psychoactive substances (NPSs), developing a rapid, easily operable method to detect NPSs in oral fluid is of high priority. Their ease of collection and non-invasive nature make oral fluid samples suitable for on-site tests and forensic cases. Herein we report a rapid and sensitive method to screen and quantitate 11 new NPSs in oral fluid. Methods Low-temperature plasma-probe mass spectrometry (LTP-MS) was applied and, to improve the signal intensity, thermally assisted desorption was employed. Tandem mass spectrometry was performed to exclude false positive signals and to decrease noise at the m/z values of interest. Results Linearity was studied using matrix-matched calibration curves; all the analytes exhibited good linearity with R2 varying from 0.9907 to 0.9981. The estimated limits of detection (LODs) were in the range of 3.0-15.2 ng/mL, which are comparable to those of immunoassay; relative standard deviations (RSDs) are no greater than 23% at the studied concentration levels. Conclusions The proposed LTP-MS-based method was promising in forensic and on-site applications to curb the abuse of NPSs.

The online coupling of surface plasmon resonance (SPR) with mass spectrometry (MS) has been highly desired for the complementary information provided by each of the two techniques. In this work, a novel interface for direct and online coupling of SPR to direct analysis in real time (DART) MS was developed. A spray tip connected with the outlet of the SPR flow solution was conducted as the sampling part of the DART-MS, with which the online coupling interface of SPR-MS was realized. Four model samples, acetaminophen, metronidazole, quinine, and hippuric acid, dissolved in three kinds of common buffers were used in the SPR-DART-MS experiments for performance evaluation of the interface and the optimization of DART conditions. The results showed consistent signal changes and high tolerance of nonvolatile salts of this SPR-MS system, demonstrating the feasibility of the interface for online coupling of SPR with MS and the potential application in the characterization of interaction under physiological conditions.

High-internal-phase-emulsion polymers (polyHIPEs) show great promise as solid-phase-extraction (SPE) materials because of the tremendous porosity and highly interconnected framework afforded by the high-internal-phase-emulsion (HIPE) technique. In this work, polyHIPE monolithic columns as novel SPE materials were prepared and applied to trace enrichment of cytokinins (CKs) from complex plant samples. The polyHIPE monoliths were synthesized via the in-situ polymerization of the continuous phase of a HIPE containing styrene (STY) and divinylbenzene (DVB) in a stainless column, and revealed highly efficient and selective enrichment ability for aromatic compounds. Under the optimized experimental conditions, a method using a monolithic polyHIPE column combined with liquid chromatography–electrospray tandem mass spectrometry (LC–MS–MS) was developed for the simultaneous extraction and sensitive determination of trans-zeatin (tZ), meta-topolin (mT), kinetin (K), and kinetin riboside (KR). The proposed method had good linearity, with correlation coefficients (R 2) from 0.9957 to 0.9984, and low detection limits (LODs, S/N = 3) in the range 2.4–47 pg mL−1 for the four CKs. The method was successfully applied to the determination of CKs in real plant samples, and obtained good recoveries ranging from 68.8 % to 103.0 % and relative standard deviations (RSDs) lower than 16 %.

The design of electron transport layers (ETLs) is crucial to the performance of optoelectronic devices. A composite ETL was constructed to overcome the poor carrier extraction issue in perovskite solar cells, resulting in a maximum PCE of 19.14% with reduced hysteresis. A similar enhancement phenomenon was observed in both devices based on TiO2 and SnO2 ETLs.

Lipids are important components of cell membranes and thylakoids in cyanobacteria, and they play vital roles in various biological activities. Real-time tracing of the variation of membrane lipids can provide insights of the physiological status of cyanobacterial cells. In this work, easy ambient sonic-spray ionization mass spectrometry (EASI-MS) was utilized to investigate the changes of acidic lipids in unicellular (Synechocystis 6803, Synechococcus 7002) and filamentous (Anabaena 7120) cyanobacteria during different growth phases. A sqdX mutant with a reduced synthesis of sulfoquinovosyl diacylglycerol (SQDG) was constructed to verify the acquired data of EASI-MS. Principal component analysis (PCA) was performed to compare the acquired data, enabling the discrimination of different species of cyanobacteria in day-to-day analysis. The results showed that the three representative cyanobacteria and their growth status can be easily determined on the basis of the lipids components detected by EASI-MS. Very interestingly, significant decreases of the ratios of SQDG/PG and dramatic changes of the unsaturation level of lipids were observed in different culture times in these cyanobacteria, and these two unique characters can be used describe the aging of cyanobacteria.

Because of less functionally critical carbohydrate sectors that contributed to the stability, efforts have been made to quantify intact recombinant human erythropoietin. A simple, rapid capillary electrophoresis with laser-induced fluorescence method for the assay of recombinant human erythropoietin was developed, with a limit of detection of intact recombinant human erythropoietin at subnanomolar concentration (up to 10 ng/mL or 3 × 10(-10) M), which is among the lowest reported. High sensitivity was accomplished by precolumn derivatization with the noncovalent dye NanoOrange. Capillary electrophoresis separation and reaction conditions were carefully manipulated for avoiding microheterogeneity of glycoforms and inhomogeneity of multiple labeling products. The fluorescence signal was linear over the range of 10 ng/mL-10 μg/mL, corresponding to the detection requirement of recombinant human erythropoietin in biofluids and pharmaceutical samples, as demonstrated by a real sample analysis. Although the salt in reaction mixtures showed a detrimental effect on the fluorescence of the derivatives, this method could tolerate a certain amount of salt, extending its application in biofluid analysis. In addition, zero-order fluorescence emission kinetics was obtained, indicating that the rapid decay of recombinant human erythropoietin was derived from a self-quenching effect.

3D porous MnO/C anode materials with controllable pore size are rationally designed and synthesized by a facile template-free strategy. The MnxZn1–xCO3 (x = 1, 2/3, 1/2 and 1/3) precursors were prepared by an ultrasonic-assisted co-precipitation method, and then heated with glucose in a reducing atmosphere to obtain a series of MnO/C microspheres through topochemical conversion. These MnO/C microspheres consist of nanosized primary particles and have interconnected pore architectures with high specific surface areas of up to 111.4 m2 g−1. Adjusting the Zn/Mn molar ratio of MnxZn1–xCO3 can easily tune the pore size of the MnO/C materials from 14.9 nm to 31.8 nm. Electrochemical performances of the MnO/C materials were found to be strongly correlated with their porous structures. The MnO/C material with optimized pore size exhibits a high reversible capacity (846 mA h g−1 at 100 mA g−1), superior rate capability (406 mA h g−1 at 3200 mA g−1) and excellent cycling stability. This strategy can be extended to prepare other candidate electrode materials.

With the amounts and types of new psychoactive substances (NPSs) increasing rapidly in recent years, an excellent high-throughput method for the analysis of these compounds is urgently needed. In this article, a rapid screening method and a quantitative analysis method for 11 NPSs are described and compared, respectively.A simple direct analysis in real time mass spectrometry (DART-MS) method was developed for the analysis of 11 NPSs including three categories of these substances present on the global market such as four cathinones, one phenylethylamine, and six synthetic cannabinoids. In order to analyze these compounds quantitatively with better accuracy and sensitivity, another rapid analytical method with a low limit of detection (LOD) was also developed using liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (LC/QTOFMS).The 11 NPSs could be determined within 0.5 min by DART-MS. Furthermore, they could also be separated and determined within 5 min by the LC/QTOFMS method. The two methods both showed good linearity with correlation coefficients (r(2) ) higher than 0.99. The LODs for all these target NPSs by DART-MS and LC/QTOFMS ranged from 5 to 40 ng mL(-1) and 0.1 to 1 ng mL(-1) , respectively. Confiscated samples, named as "music vanilla" and "bath salt", and 11 spiked samples were firstly screened by DART-MS and then determined by LC/QTOFMS.The identification of NPSs in confiscated materials was successfully achieved, and the proposed analytical methodology could offer rapid screening and accurate analysis results. Copyright © 2016 John WileySons, Ltd.

Glycerolipid is a main component of membranes in oxygenic photosynthetic organisms. Up to now, the majority of publication in this area has focused on the physiological functions of glycerolipids and lipoprotein complexes in photosynthesis, but the study on the separation and identification of glycerolipids in thylakoid membrane in cyanobacteria is relatively rare. Here we report a new method to separate and identify five photosynthetic glycerolipid classes, including monoglucosyl diacylglycerol, monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol, in cyanobacteria Synechococcus sp. PCC 7002 by two-dimensional (normal- and reversed-phase) liquid chromatography online coupled to quadrupole time-of-flight mass spectrometry. Over twice as many lipid species were detected by our method compared to the previously reported methods. Ten new odd-chain fatty acid glycerolipids were discovered for the first time. Moreover, complete separation of isomers of monogalactosyl diacylglycerol and monoglucosyl diacylglycerol was achieved. According to the tandem mass spectrometry results, we found that the head group of monoglucosyl diacylglycerols was not as stable as that of monogalactosyl diacylglycerols, which might explain why the organism chose monogalactosyl diacylglycerols and digalactosyl diacylglycerols instead of monoglucosyl diacylglycerols as the main content of the photosynthetic membranes in the history of evolution. This work will benefit further research on the physiological function of glycerolipids.

Jasmonic acid (JA) is an essential plant hormone involved in plant development and defense system. There are four stereoisomeric forms of JA and they act quite differently in vivo. In this work, a normal phase liquid chromatography-quadrupole time-of-flight mass spectrometry (NPLC-QTOF-MS) method using cellulose tris (4-methylbenzoate) coated silica gel as the chiral stationary phase was first established for the simultaneous discrimination and direct analysis of all the four JA stereoisomers without need of derivatization. A non-endogenous JA stereoisomer was introduced as the internal standard to ensure the reliability of the developed method. Satisfactory results were obtained in terms of sensitivity (limit of detection, 0.5 ng mL(-1) or 2.4 fmol), linearity (R(2)=0.9996) and repeatability (run-to-run RSD of migration time and peak area, 0.37% and 5.9%, respectively, n=6). Endogenous rise of two natural JA stereoisomers was detected in tobacco leaves and their variations in response to mechanical wounding were monitored. In addition, the configurational stability of JA stereoisomers was investigated using the stereoisomerically pure forms which were not commercially available but easily obtained by our semi-preparative chiral LC method. Experimental evidence indicated that both of the two naturally existing JA stereoisomers were putative signals for wounding response, and the epimerization between them was not a spontaneous process simply promoted by the thermodynamical instability as expected before.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) with one chiral center at the carbinol is a major metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). As tobacco specific N-nitrosamines (TSNAs), NNK and NNAL are the most pulmonary carcinogens in tobacco products and smoke. In this paper, a chiral CE method modified with highly sulfated β-cyclodextrin (S-β-CD) was developed to investigate the stereoselective formation of NNAL from NNK in vitro in normal human bronchial epithelial (NHBE) cells. Combined with solid phase extraction (SPE) of the cell samples, NNK and NNAL enantiomers were baseline separated under the proposed CE conditions, with satisfactory recoveries (72.5-113% for NNK and (±)-NNAL) and low limits of detection (LOD, 2.5-3 μg/mL for NNK and (±)-NNAL). The cytotoxicity of NNK in NHBE cells was investigated through the cell counting kit (CCK) assay and proved to be highly dependent on the NNK's concentration. The metabolic results obtained from CE analysis demonstrated that NNK was preferentially metabolized to (+)-NNAL through carbonyl reduction. Meanwhile, the ratio of [(+)-NNAL]/[(-)-NNAL] was independent of NHBE cells' incubation time with NNK, but could be changed according to the original incubation concentration of NNK. This chiral CE method could be useful for the study on toxicology and metabolic transformations of related TSNAs.

Lipidomics, as a novel branch of metabolomics, which is aimed at comprehensive analysis of lipids and their biological roles with respect to health and diseases, has attracted increased attention from biological and analytical scientists. As a result of the complexity and diversity of lipids, accurate identification and efficient separation are required for lipidomics analysis. Mass spectrometry (MS) and chromatography have been extensively developed in the past few decades and hold a distinguished position in qualification and separation science. They are powerful and indispensable tools for lipidomics. Herein, we present the recent advancement of MS, chromatography, and their hyphenation technologies in lipidomics.

Serotonin is an important neurotransmitter that regulates a wide range of physiological, neuropsychological, and behavioral processes. Consequently, serotonin deficiency is involved in a wide variety of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, schizophrenia, and depression. The pathophysiological mechanisms underlying serotonin deficiency, particularly from a lipidomics perspective, remain poorly understood. This study therefore aimed to identify novel lipid biomarkers associated with serotonin deficiency by lipidomic profiling of tryptophan hydroxylase 2 knockout (Tph2-/-) mice. Using a high-throughput normal-/reversed-phase two-dimensional liquid chromatography-quadrupole time-of-flight mass spectrometry (NP/RP 2D LC-QToF-MS) method, 59 lipid biomarkers encompassing glycerophospholipids (glycerophosphocholines, lysoglycerophosphocholines, glycerophosphoethanolamines, lysoglycerophosphoethanolamines glycerophosphoinositols, and lysoglycerophosphoinositols), sphingolipids (sphingomyelins, ceramides, galactosylceramides, glucosylceramides, and lactosylceramides) and free fatty acids were identified. Systemic oxidative stress in the Tph2-/- mice was significantly elevated, and a corresponding mechanism that relates the lipidomic findings has been proposed. In summary, this work provides preliminary findings that lipid metabolism is implicated in serotonin deficiency.

In this work, polymerized high internal phase emulsion (polyHIPE) monoliths were prepared and applied as monolithic adsorbent materials for proconcentration of trace polycyclic aromatic hydrocarbons (PAHs) from large-volume water samples. The monolithic polyHIPE columns were prepared by in situ polymerization of the continuous phase of a high internal phase emulsion (HIPE) containing styrene (STY), divinylbenzene (DVB) and glycidyl methacrylate (GMA) in pipette tips, and the resulting STY/DVB/GMA polyHIPE monoliths exhibited highly interconnected porosity and large surface areas, making them excellent candidates as adsorbents for enrichment of trace aromatic compounds. The prepared STY/DVB/GMA polyHIPE monoliths were applied to the determination of trace PAHs in environmental water samples by combing with high performance liquid chromatography-fluorescence detection (HPLC-FLD). Under the optimized experimental conditions, the polyHIPE monoliths could effectively enrich trace 13 PAHs from 500mL of water samples, the mean recoveries at four spiked levels were ranged from 80.7% to 115.0% with the relative standard deviations (RSDs) lower than 14%, and the detection limits (LODs) were ranged from 4.0 to 228pg/L. In addition, the prepared polyHIPE monolith was stable enough for more than 200 replicate extraction cycles without measurable loss of performance on the enrichment of PAHs, and good column-to-column repeatability was obtained with RSD less than 13%. The proposed method was applied to simultaneous analysis of 13 PAHs in water samples with satisfactory recoveries.

Accumulating evidence suggests that hypoxia-inducible factor 1α (HIF-1α) regulates numerous miRNAs and is crucial for cellular response to hypoxia. However, the relationship between HIF-1α and miR-21 in hypoxic cardiomyocytes is little known. We found that hypoxia induced HIF-1α and miR-21 expression. HIF-1α knockdown increased cell apoptosis and reduced miR-21 expression. Furthermore, we found that HIF-1α transcriptionally enhanced miR-21 promoter activity by binding to its promoter, which required the recruitment of CBP/p300. In addition, we found that miR-21 inhibition increased cell apoptosis and reduced HIF-1α expression, and modulated the PTEN/Akt pathway. Our results indicate that HIF-1α-miR-21 feedback contributes to the adaptation of cardiomyocytes to hypoxia, and has potential as therapeutic target for myocardial ischemia.

Because of less functionally critical carbohydrate sectors that contributed to the stability, efforts have been made to quantify intact recombinant human erythropoietin. A simple, rapid capillary electrophoresis with laser-induced fluorescence method for the assay of recombinant human erythropoietin was developed, with a limit of detection of intact recombinant human erythropoietin at subnanomolar concentration (up to 10 ng/mL or 3 × 10(-10) M), which is among the lowest reported. High sensitivity was accomplished by precolumn derivatization with the noncovalent dye NanoOrange. Capillary electrophoresis separation and reaction conditions were carefully manipulated for avoiding microheterogeneity of glycoforms and inhomogeneity of multiple labeling products. The fluorescence signal was linear over the range of 10 ng/mL-10 μg/mL, corresponding to the detection requirement of recombinant human erythropoietin in biofluids and pharmaceutical samples, as demonstrated by a real sample analysis. Although the salt in reaction mixtures showed a detrimental effect on the fluorescence of the derivatives, this method could tolerate a certain amount of salt, extending its application in biofluid analysis. In addition, zero-order fluorescence emission kinetics was obtained, indicating that the rapid decay of recombinant human erythropoietin was derived from a self-quenching effect.

In this paper, a micellar electrokinetic chromatography (MEKC) method combined with cation-selective exhaustive injection (CSEI) and sweeping was developed to separate and concentrate four tobacco-specific N-nitrosamines (TSNAs) including N′-nitrosoanabasine (NAB), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and 4-(methylnitrosamino)-4-(3-pyridyl)-1-butanol (iso-NNAL). Experimental parameters affecting separation efficiency and enhancement factors were investigated in detail. Under the optimum MEKC condition, NAB, NNK, NNAL and iso-NNAL were baseline separated with high separation efficiencies and good peak shapes. Furthermore, with the preconcentration by CSEI–sweeping–MEKC, the sensitivity enhancement factors for NAB, NNK, NNAL and iso-NNAL in terms of peak areas ranged from 6.0 × 10 3 to 1.5 × 10 4 , and the detection limits (LOD, S/N = 3) of four TSNAs were in the range of 0.004–0.016 μg/mL. In addition, this method had fairly good repeatability, and the RSDs of retention time and peak area were less than 1% and 5%, respectively. Finally, this method showed promising capabilities in the application of detecting and analyzing TSNAs in human urine samples.

A CE-MS method for rapid determination of aristolochic acid-I and aristolochic acid-II (AA-II) in traditional Chinese medicines and biological samples was described in the present paper. AA-I and AA-II can be baseline separated within 6 min by CE-MS with carboxymethyl-chitosan-coated capillary. CZE conditions including pH, concentration of buffer, applied voltage, and capillary temperature were systematically investigated, and the composition and flow rate of sheath liquid were also optimized for CE-MS. Furthermore, the CE-UV method without any additives in BGE solution was established and compared with the CE-MS method. The results showed that the two methods could achieve satisfactory separation efficiency, repeatability, and linearity, while the LOD was 0.6 microg/mL for CE-UV and 0.05 microg/mL for CE-MS. Compared with the CE-UV method, the sensitivity of CE-MS was significantly improved, in addition to the structure information provided by MS detection at the same time. As an application example, a spiked sample in human serum was analyzed by the CE-MS method, indicating that the new CE-MS method can be applied to analyze AAs in biological samples.

BACKGROUND High peritoneal transport status in end-stage renal disease patients receiving peritoneal dialysis was shown to be associated with increased morbidity and mortality. Although the pathogenesis of increased peritoneal transport is still not clear, previous studies have demonstrated that phospholipids (PLs) are present on the peritoneal mesothelium and when added to dialysate can decrease the peritoneal fluid absorption rate and increase peritoneal fluid removal. In the present report, we explored the relationship between peritoneal transport and dialysate loss of endogenous PLs. METHODS We evaluated 48 prevalent continuous ambulatory peritoneal dialysis patients with high or low peritoneal transport in a cross-sectional study. The 4-hour dwell dialysate PL profile was analyzed by high-performance liquid chromatography coupled with electrospray ionization ion trap mass spectrometry. The patients' peritoneal small solute transport rate was assessed by D/P(Cr) at 4 h and their fluid transport by kinetic modeling. RESULTS While there were no significant differences between the 2 groups in age, sex, diabetic status and time on dialysis, high transporters had a significantly higher D/P(Cr) and peritoneal fluid absorption rate (K(e)) than low transporters. The PLs in dialysate effluents mainly consisted of PLs containing unsaturated fatty acid, and the concentrations, as well as the amount, of PLs were significantly elevated in the dialysate of high transporters as compared to low transporters. CONCLUSION Our results showed that dialysate from high transporters exhibited elevated levels of PLs, especially PLs containing unsaturated fatty acid, suggesting a possible loss of peritoneal surface-active PLs in peritoneal dialysis, and this loss may contribute to the alteration in peritoneal transport.