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To explore the antitumor and potential off-target effects of systemically delivered cholesterol-conjugatedThe antitumor effects of two intravenous dosing regimens ofContinuous treatment with

Hydrogen transfer (H-transfer) is an important elementary reaction in chemistry and bioscience. It is often facilitated by the hydrogen bonds between the H-donor and acceptor. Here, at room temperature and high pressure, we found that solid 2-butyne experienced a concerted two-in-two-out intermolecular CH···π H-transfer, which initiated the subsequent polymerization. Such double H-transfer goes through an aromatic Hückel six-membered ring intermediate state via intermolecular CH···π interactions enhanced by external pressure. Our work shows that H-transfer can occur via the CH···π route in appropriate conformations under high pressure, which gives important insights into the H-transfer in solid-state hydrocarbons.

Free fatty acids are involved in many metabolic regulations in the human body. In this work, an ultra-fast screening method was developed for the analysis of free fatty acids using trapped ion mobility spectrometry coupled with mass spectrometry. Thirty-three free fatty acids possessing different unsaturation degrees and different carbon chain lengths were baseline separated and characterized within milliseconds. Saturated, monounsaturated, and polyunsaturated free fatty acids showed different linearities between collision cross-section values and m/z. The establishment of correlations between structures and collision cross-section values provided additional qualitative information and made it possible to determine free fatty acids which were out of the standards pool but possessed the confirmed linearity. The gas-phase separation made the quantitative analysis reliable and repeatable at a much lower time cost than chromatographic methods. The sensitivity was comparable to and even better than the reported results. The method was validated and applied to profiling free fatty acids in human plasma. Saturated free fatty acids abundance in the fasting state was found to be lower than that in the postprandial state, while unsaturated species abundance was found higher. The method was fast and robust with minimum sample pretreatment, so it was promising in the high-throughput screening of free fatty acids.

An efficient and environment-friendly method for simultaneous determination of 13 typical derivatives of polycyclic aromatic hydrocarbon (PAH) in petroleum-polluted soil with nitro-, oxy- and alkyl-functional group was developed using supercritical fluid extraction (SFE) followed by ultra-high performance supercritical fluid chromatography (UHPSFC). Parameters of UHPSFC, including type of stationary phase and mobile phase modifiers, gradient elution process, backpressure, column temperature, and the flow rate of mobile phase, were systematically optimized, achieving a fast separation within 4.2 min. Limits of detection (LOD) were 0.005–0.1 μg mL−1 or 0.1–2.0 ng g−1, respectively, with a good repeatability (RSD

The design of efficient nanostructured catalysts is highly desirable for promoting the hydrogenation of 4-carboxybenzaldehyde (4-CBA), which are the key process of hydrorefining of crude terephthalic acid (CTA) to pure terephthalic acid (PTA). Herein, the Pt-FeNi@C, Pt-Fe@C and Pt-Ni@C catalysts were developed and proved to be active for the selective hydrogenation of 4-CBA. As a result, the excellent 4-hydroxymethylbenzoic acid (4-HMBA) selectivity (85%) and benzoic acid (BA) selectivity (88%) were achieved on Pt-FeNi@C and Pt/C, respectively. In comparison with the commercial Pd/C catalyst, the Pt-FeNi@C catalyst exhibits excellent activity (97%) and reduces the occurrence of decarbonylation. Moreover, the Pt-FeNi@C catalyst exhibits excellent recyclability: the catalytic activity did not decrease significantly after four reaction cycles. In combination with detailed characterization, the Pt-FeNi@C catalyst has porous graphene core-shell architecture and remarkable electron transfer capacity. This work may provide some inspirations for the exploration of new PTA hydrofining catalysts.

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.

Thiophene compounds are the main concern of petroleum desulfurization, and their chemical composition and molecular configuration have critical impacts on thermodynamic and kinetic processes. In this work, atmospheric pressure chemical ionization (APCI) was employed for effective ionization of thiophene compounds in petroleum with complex matrix, in which carbon disulfide was used for generating predominant [M]+• ions without the need of derivatization as for electrospray ionization. APCI coupled with ultrahigh-resolution mass spectrometry (UHRMS) was successfully applied to the composition characterization of thiophene compounds in both a low boiling petroleum fraction and a whole crude oil. APCI coupled with trapped ion mobility spectrometry (TIMS) was developed to determine the shape and size of thiophene compounds, providing configuration information that affects the steric hindrance and diffusion behavior of reactants in the desulfurization reaction, which has not been previously reported. Moreover, the comprehensive experimental structural data, expressed as the collision cross section (CCS) of the ions as surrogates of molecules, provided clues to the factors affecting the desulfurization reactivity of thiophene compounds. Further exploration showed that not only qualitative analysis of thiophene compounds can be achieved from the correlation between m/z and CCS, but also molecular size was found to be correlated with CCS that can be used as structural analysis. Overall, the molecular composition and dimension analysis together can provide substantial information for the desulfurization activity of thiophene compounds, facilitating the desulfurization process studies and catalyst design.

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 composite chloroaluminate ionic liquid (IL) modified with copper(I) chloride has attracted considerable attention due to its high catalytic activity and selectivity for isobutane alkylation, where the bimetallic anions of Cu(I)-Al(III) have been proposed to play important roles. Characterization of chloroaluminate and composite ionic liquids (CIL) is crucial for a better understanding of alkylation mechanism and catalysts design. In this work, a plasma-based ion source, direct analysis in real time (DART), was introduced to achieve soft but effective ionization of chloroaluminate IL and CIL with minimized hydrolysis, fragmentation and salt effects. Combined with the isotope patterns strategy and high-energy collision dissociation (HCD) technology, this developed high resolution mass spectrometry (HRMS) method, DART-Orbitrap-HRMS, was not only able to identify the accurate chemical composition of chloroaluminate IL and CIL, but also capable of structure analysis. Based on the comparison of chloroaluminate IL and CIL, it showed that similar acidic anions in both ILs were [AlCl4]−, [Al2Cl7]− and [Al3Cl10]−. The remarkable difference was the verification of Cu(I)-Al(III) bimetallic anions as [CuAlCl5]− and [CuAl2Cl8]− merely in CIL, which were proposed to count for the high catalytic activity. Moreover, Cu(I) cation ion that might be related to the alkylation selectivity was characterized as [(Et3NH)2CuCl2]+ in CIL. Structure analysis of the two bimetallic anions were then achieved by HCD technology. All the results have provided substantial support for the structure-activity study of CIL, setting the stage for in-depth research on IL-catalyzed isobutane alkylation.

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.

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.

Pressure-induced polymerization (PIP) of metal acetylides is a novel method to synthesize a metal–carbon framework and polycarbide materials with unique structures and properties. However, the pres...

International audience; Vanadyl porphyrins in the heavy crude oil were enriched and characterized by trapped ion mobility spectrometry-time of flight mass spectrometry (TIMS-TOF MS) and Fourier transform ion cyclotron resonance mass spectrometry. Two series of mobiligram peaks were present in the extracted ion mobility spectra of the petroporphyrins. Collision induced dissociation (CID) revealed that one peak series was [M + H]+, while the other peak series was cluster ions, which may contain an amine in the ions. Model compounds were used to investigate the aggregation and fragmentation behavior of porphyrin ions. It was found that all the porphyrins tend to form adduct ions in the electrospray ionization, such as [2 M]+, [2 M + H]+, [2 M + Na]+ and cluster ions of porphyrin with other compounds. This implies the strong molecular aggregation potential of porphyrins with themselves and other petroleum molecules. The porphyrin cluster ions generated in ionization source could decompose and continuously disaggregate during the transmission in the MS. The [M]+ and [M + H]+ were dissociated into fragment ions and the cluster ions were disaggregated into [M]+ and [M + H]+ simultaneously with high collision energy. The CID analysis of Zn-OEP porphyrin showed that [M + H]+ has a lower dissociation energy than [M]+. The results provide instructive information for the understanding of aggregation and fragmentation behavior of petroporphyrins as well petroleum asphaltenes.

Sulfur-containing compounds (SCCs) are the most abundant heteroatom compounds in petroleum. The characterization of SCCs in crude oils and petroleum products has great importance not only for the downstream refining process control/optimization and environmental compliance but also for upstream geochemical studies for exploration and production. In recent years, a variety of methods to analyze SCCs have been developed and practiced where chromatography and mass spectrometry have played major roles. This review summarizes the analytical strategy and some of the most important and promising technologies, from sample pretreatment to molecular level characterization. For the convenience of discussions and practical applications, we divide the petroleum mixtures containing sulfur components into gas chromatography (GC)-amenable and nonvolatile fractions. For the former, gas chromatography (GC) and comprehensive two-dimensional gas chromatography (GC × GC) utilizing sulfur-selective detectors or mass spectrometry (GC–MS) are predominant analytical techniques. For the latter, molecular characterization is much more difficult and challenging. High performance liquid chromatography (HPLC) or direct liquid infusion and its combination with mass spectrometry (LC–MS), especially ultra-high resolution mass spectrometry, such as Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and Orbitrap MS, associated with various atmospheric ionization techniques are the most practical approaches. Some ionization techniques are underutilized, such as atmospheric pressure chemical ionization (APCI). The use of surface desorption ionization techniques, direct electrospray ionization (DSEI) and desorption atmospheric chemical ionization (DAPCI), for the molecular characterization of insoluble kerogens that has been characterized by X-ray near edge structure spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS) remain to be explored.

Diacylglycerols (DAGs) ions, instead of triacylglycerols (TAGs) ions, were established as marker indicators for an improved classification of edible oils using ultrahigh resolution mass spectrometry (UHRMS). DAGs ions can be used not only to identify triacylglycerols (TAGs) and their embedded fatty acids (FAs), but also to distinguish positional isomers of TAGs. In this work, DAGs ions were determined in edible oils by direct infusion atmospheric pressure chemical ionization-ultrahigh resolution mass spectrometry (APCI-UHRMS), where the ultrahigh resolving power up to 500,000 FWHM (full width at half maximum) can provide accurate molecular compositions and detailed fingerprints MS spectra in a minute. A total of 146 samples belonging to 22 species of plant oils and animal fats, were characterized. Chemometric analyses were performed using principal component analysis, partial least square-discriminant analysis and orthogonal partial least squares-discriminant analysis. DAGs ions were proved to be better than TAGs ions as marker indicators in the chemometric analyses. An overall correct rate of 93.40% was achieved for the classification of tested samples. In addition, blend oils and gutter oils were also characterized by this developed method.

Sulfur compounds in deep hydrodesulfurization (HDS)-derived diesels were effectively separated into thiophenic and sulfidic fractions using the methylation/demethylation method and characterized by gas chromatography–mass spectrometry (GC–MS) and GC–sulfur chemiluminescence detector (SCD). Sulfidic fractions account for over 15 wt % of total residual sulfur, in which a series of refractory cyclic sulfidic compounds, 1,1-dimethylhexahydrodibenzothiophenes (1,1-DMH6DBTs) and 1,9b-dimethylhexahydrodibenzothiophenes (1,9b-DMH6DBTs), were found in the diesels, and larger molecular weight homologues were identified. Some homologue series of C1–C4 alkyl-substituted thiaadamantanes were detected in the HDS diesel. These cyclic sulfidic components are refractory to deep HDS, which require more prudent catalysis and reaction systems to achieve ultralow-sulfur diesel (ULSD) production.

Bio-oils, produced by biomass pyrolysis, have become promising candidates for feedstocks of high value-added chemicals and alternative sources for transportation fuels. Bio-oil is such a complicated mixture that contains nonpolar hydrocarbons and polar components which cover almost all kinds of organic oxygenated compounds such as carboxylic acids, alcohols, aldehydes, ketones, esters, furfurals, phenolic compounds, sugar-like material, and lignin-derived compounds. Comprehensive characterization of bio-oil and its subfractions could provide insight into the conversion process of biomass processing, as well as its further utilization as transportation fuels or chemical raw materials. This review focuses on advanced analytical strategies on in-depth characterization of bio-oil, which is concerned with gas chromatography, high-resolution mass spectrometry, FTIR spectroscopy and NMR spectroscopy, offering complementary information for previous reviews.

Negative- and positive-ion direct analysis in real time (DART) ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was applied to characterize crude oil and its fractions. Crude oil samples dissolved in toluene were directly infused into a spray needle, which produced a continuous and long-time stable ion current for FT-ICR MS analysis to obtain mass spectra with a broad dynamic range and high signal-to-noise ratio. A comparison between negative-ion electrospray ionization [ESI(−)] and negative-ion DART for crude oil analysis was presented. The DART(−) ionized almost all of the compound classes found in ESI(−), while it exhibited high selectivity on naphthenic acids, which enabled the characterization of naphthenic acids in petroleum with a low total acid number (TAN). The method is suitable for the analysis of naphthenic acids in petroleum distillation cuts, even with a very high boiling point. Sulfides in petroleum were likely oxidized to sulfoxides and exhibite...

A three-step supercritical CO 2 extraction was used for selective fractionation of fast pyrolysis bio-oil. Oxygen-containing compounds in bio-oil and its fractions were characterized using infrared spectroscopy (IR), 1 H nuclear magnetic resonance spectroscopy (NMR), gas chromatography–mass spectrometry (GC–MS) and negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). With appropriate optimization of extraction parameters, lipids, hemicellulose, lignin and condensed aromatics were found enriched in three different fractions. The molecular composition and compound classes were identified by combined analytical techniques, and the selectivity of the fractionation was proved. The compound-type-specific fractionation also facilitated the following characterization and provided insights into the chemical composition of bio-oil. Results indicated that CO 2 supercritical fluid extraction was potential for bio-oil preprocessing.

This article presented a brief introduction to gas chromatography (GC) fundamentals concerned with both the thermodynamic process and the kinetic process, in terms of plate theory and rate theory. Evaluation and optimization of GC separation as well as column efficiency were discussed theoretically and practically. Other than conventional GC, principles of fast GC, two-dimensional GC, and microfabricated GC were also covered.

Normal phase chiral LC (NPLC) has been proved to be powerful and efficient for chiral separation. However, the combination of NPLC with ESI or atmospheric pressure chemical ionization MS is restricted by the poor ionization efficiency and thermal fragmentations of analytes to some extent. Direct analysis in real time MS (DART-MS) is an ambient ionization technique that shows high ionization efficiency of the analytes in the normal phase mobile phase. In this work, we coupled chiral NPLC to DART-MS for the chiral qualitative and quantitative analysis of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and jasmonic acid enantiomers. Satisfactory results for the enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol operating in the positive mode were obtained in terms of linearity (2.5-250 μg/mL, R(2) , 0.999-1.000) and repeatability (25 μg/mL, RSDs, 4.7-5.6%). Moreover, chiral NPLC-DART-MS resulted in the simultaneous chiral separation and detection of jasmonic acid enantiomers, which are very difficult to be analyzed by NPLC-ESI-MS and NPLC-APCI-MS. Compared with the coupled techniques of NPLC-ESI-MS and NPLC-APCI-MS, NPLC-DART-MS showed advantages in increasing the ionization efficiency and reducing the in-source thermal fragmentation of analytes.

In this work, a new labeling reagent, 2-bromopyridine-5-boronic acid (BPBA), was introduced to derivatize brassinosteroids (BRs). The BPBA not only provided a very simple and rapid labeling procedure, but also remarkably increased the detection sensitivity of BRs. Based on this new labeling reaction, a rapid and sensitive method for BRs' analysis in Arabidopsis thaliana was established by using the ultra high performance liquid chromatography-electrospray ionization triple quadrupole mass spectrometry (UHPLC-ESI-QqQ-MS). The extraction and purification procedure of the plant sample was also simplified and improved in this work. Good linearities were obtained for three BRs with the determination coefficients (R(2)) about 0.9999. The limits of detection (S/N=3) for three BRs were found to be 2.00-8.00 ng/L while the limits of quantification (S/N=10) were 6.00-23.0 ng/L. The RSD % for all three samples are lower than 8.67% (n=5). The recoveries of three BRs spiked in A. thaliana samples were from 76.9% to 86.1%. Using this method, the endogenous 0.055 ng/g fresh weight (FW) 24-epiBR and 0.070 ng/g (FW) 28-epihomoBR were successfully detected from only 2g A. thaliana plants.

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.

Superparamagnetic iron oxide nanoparticles (SPION) have attracted great attention for nanomedical applications, but the mechanisms underlying the transmembrane transport of SPION in variant cells has not been fully defined. The present study investigated the internalization of SPION in three cell models with different phagocytic capacity using transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) analyses. The EDS study aimed to further confirm if the suspected internalized particles were iron-containing SPION. SPION could be taken up quickly by macrophage-like cell line RAW264.7 (with strong phagocytic capacity) and slowly by the 3T3-L1 cells (with weak phagocytic capacity), but not by red blood cells (with no phagocytic capacity). The internalized SPION were mainly found in the cytoplasmic vesicles, with no localization in the endoplasmic reticulum, mitochondria and nucleus. We conclude that the internalization of SPION in the three types of mammalian cells was mediated by phagocytosis, not by direct membrane penetration.

Normal phase chiral LC (NPLC) has been proved to be powerful and efficient for chiral separation. However, the combination of NPLC with ESI or atmospheric pressure chemical ionization MS is restricted by the poor ionization efficiency and thermal fragmentations of analytes to some extent. Direct analysis in real time MS (DART-MS) is an ambient ionization technique that shows high ionization efficiency of the analytes in the normal phase mobile phase. In this work, we coupled chiral NPLC to DART-MS for the chiral qualitative and quantitative analysis of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and jasmonic acid enantiomers. Satisfactory results for the enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol operating in the positive mode were obtained in terms of linearity (2.5-250 μg/mL, R(2) , 0.999-1.000) and repeatability (25 μg/mL, RSDs, 4.7-5.6%). Moreover, chiral NPLC-DART-MS resulted in the simultaneous chiral separation and detection of jasmonic acid enantiomers, which are very difficult to be analyzed by NPLC-ESI-MS and NPLC-APCI-MS. Compared with the coupled techniques of NPLC-ESI-MS and NPLC-APCI-MS, NPLC-DART-MS showed advantages in increasing the ionization efficiency and reducing the in-source thermal fragmentation of analytes.

Jasmonic acid (JA), an essential plant hormone controlling the plant defense signaling system and developmental processes, has stereospecific bioactivities that have not been well understood mainly due to the limitation in separation and detection methodologies. In this work, a fast CE-UV method based on short-end injection technique and a sensitive CE-QTOF-MS method based on partial filling technique were successfully developed for the enantioseparation of racemic JA. The successive coating technique was also involved by modifying the capillary with multiple ionic polymer layers of polybrene-dextran sulfate-polybrene. This was the first report on the direct resolution of both pairs of JA enantiomers, including two naturally occurring JA stereoisomers. Although no pure JA stereoisomers were commercially available, all the separated JA stereoisomers were identified indirectly by comparing the difference between the racemic standard and plant samples based on the presence and the ratio of each stereoisomer. Satisfactory results were obtained in terms of sensitivity (LOD, 24 ng/mL or 0.7 fmol for single JA stereoisomer) using 45 mmol/L ammonium acetate at pH 4.5 containing 70 mmol/L α-CD as the buffer system. This established CE-QTOF-MS method was later successfully applied for the study of the naturally occurring JA stereoisomers in wounded tobacco leaves.

Superhydrophobic monolithic porous polymer layers with a photopatterned hydrophilic channel have been prepared. These layers were used for two-dimensional thin layer chromatography of peptides. The 50 microm thin poly(butyl methacrylate-co-ethylene dimethacrylate) layers supported onto 4.0 x 3.3 cm glass plates were prepared using UV-initiated polymerization in a simple glass mold. Photografting of a mixture of 2-acrylamido-2-methyl-1-propanesulfonic acid and 2-hydroxyethyl methacrylate carried out through a mask afforded a 600 microm wide virtual channel along one side of the layer. This channel, which contains ionizable functionalities, enabled the first dimension separation in ion exchange mode. The aqueous mobile phase migrates only through the channel due to the large difference in surface tension at the interface of the hydrophilic channel and the superhydrophobic monolith. The unmodified part of the layer featuring hydrophobic chemistry was then used for the reversed phase separation in the orthogonal second dimension. Practical application of our technique was demonstrated with a rapid 2D separation of a mixture of model peptides differing in hydrophobicity and isoelectric point using a combination of ion-exchange and reversed phase modes. In the former mode, the peptides migrated 11 mm in less than 1 min. Detection of fluorescently labeled peptides was achieved through UV light visualization. Separation of the native peptides was monitored directly using a desorption electrospray ionization (DESI) source coupled to a mass spectrometer. Unidirectional surface scanning with the DESI source was found suitable to determine both the location of each separated peptide and its molecular mass.

The quality control standards are the key points in the modernization of traditional Chinese medicines (TCM), and in recent years, the fingerprinting techniques play an increasingly important role, including fingerprintings based on gas chromatography, liquid chromatography, capillary electrophoresis, spectroscopic methods, and so on. Some advances in this area in the past few years are reviewed and some prospects are discussed in this article.

To establish a flow cytometric internal standard method for counting platelet-derived microparticles (PMPs) and to study its clinical significance.PMPs suspension (platelet poor plasma, PPP) was extracted by gradual centrifugation. According to the size of PMPs, 3 microm and 0.8 microm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter.In 30 healthy donors, the average concentration of resting PMPs was (1.2 x 10(5) +/- 5.7 x 10(4))/ml and that of activated PMPs was (1.6 x 10(6) +/- 9.1 x 10(5))/ml. Compared with healthy donors, PMPs mean value was significantly higher (P0.001) in 18 patients with coronary artery disease, 12 with acute cerebral infraction and 23 with chronic renal failure [the average PMPs concentration, (6.1 x 10(5) +/- 2.5 x 10(5))/ml, (6.8 x 10(5) +/- 3.4 x 10(5))/ml and (5.9 x 10(5) +/- 3.1 x 10(5))/ml respectively]. However, no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [(1.3 x 10(5) +/- 6.1 x 10(4))/ml, (P0.05)].PMPs is a useful indicator in monitoring platelet activation, and plays an important role in thrombotic disease. By flow cytometric internal standard method, PMPs can be counted rapidly and accurately, which may be very helpful in interlaboratory comparative studies.

The incorporation of inorganic nanoparticles (NPs) into polymers has been pursued as a route to functional materials. TiO2 is a well known multifunctional inorganic material, however, stabilizing TiO2 NPs in bulk polymer matrices to obtain optically transparent nanocomposites remains a significant challenge. Here, we report an effective strategy for the preparation of bulk transparent TiO2–polymer nanocomposites through the combined use of copolymerization of a novel titanium ion-containing monomer with a liquid–solid reaction. The titanium ions are covalently introduced into polymer chains and transformed into TiO2 NPs directly in the solid-state polymer matrices, which allows the generation of well dispersed TiO2 NPs with small size and narrow size distribution in the entire polymer matrices. The resulting transparent nanocomposites exhibit promising UV-shielding properties and consequently should have direct application in the development of transparent UV-protective materials. Moreover, the surface photocatalytic activity of the nanocomposites is helpful for realizing a pollutant- and bacteria-free surface. Moreover, europium methacrylate (Eu(MA)3) is used as a cross-linking agent, which produces cross-linked structures to enhance the stability of the nanocomposites.

The potential applications of superparamagnetic iron oxide nanoparticles (SPIONs) in several nanomedical fields have attracted intense interest based on the cell-nano interaction. However, the mechanisms underlying cell uptake, the intracellular trail, final fate and the biological effects of SPIONs have not yet been clearly elucidated. Here, we showed that multiple endocytic pathways were involved in the internalization process of SPIONs in the RAW264.7 macrophage. The internalized SPIONs were biocompatible and used three different metabolic pathways: The SPIONs were distributed to daughter cells during mitosis; they were degraded in the lysosome and free iron was released into the intracellular iron metabolic pool; and, the intact SPIONs were potentially exocytosed out of the cells. The internalized SPIONs did not induce cell damage but affected iron metabolism, inducing the upregulation of ferritin light chain at both the mRNA and protein levels and ferroportin 1 at the mRNA level. These results may contribute to the development of nanobiology and to the safe use of SPIONs in medicine when administered as a contrast medium or a drug delivery tool.