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Time-of-flight secondary ion mass spectra measured for different carbon allotropes under Bi3+ cluster ion bombardment were acquired. Ion yield of homogeneous (Cn)- and heterogeneous metal-carbon (CsCn)- secondary cluster ions was examined. Qualitative explanation of the regularities was given based on the concept of nonlinear atomic collision cascades. It was suggested that that the features of secondary cluster yield can be used for determination of hybridization state of the target material. Unlike most other techniques, secondary ion mass spectrometry is capable of the sputter depth profiling of the hybridization state.

Spectroscopic characterization of CO activation on multiple metal-containing catalysts remains an important and challenging goal for identifying the structure and nature of active site in many industrial processes such as Fischer-Tropsch chemistry and alcohol synthesis. Here, we use mass-selected photoelectron velocity-map imaging spectroscopy and quantum chemical calculations to study the reactions of CO molecules with several heterobinuclear transition metal-iron clusters M–Fe (M = Ti, V, Cr). The mass spectra reveal the favorable formation of MFe(CO)4− with relatively high thermodynamic stability. The MFe(CO)4− (M = Ti, V, Cr) complexes are established to have a metal–Fe bonded M–Fe(CO)4 structure with C3v geometry. While the positive charge and unpaired electrons are mainly located on the M atom, the natural charge of Fe(CO)4 is about −2e. The MFe(CO)4− (M = Ti, V, Cr) can be seen as being formed via the interactions between the M+ fragment and the [Fe(CO)4]2− core, which satisfies the 18-electron rule. The CO molecules are remarkably activated in these MFe(CO)4−. These results shed insight into the structure–reactivity relationship of heterobinuclear transition metal carbonyls and would have important implications for understanding of CO activation on alloy surfaces.

Echinoid pigments have various biological properties such as antioxidant, cytotoxic, and antibacterial activities. We aimed to evaluate the extraction of cell-free coelomic fluid (CFCF) and coelomocyte lysate (CL) as well as qualitatively and quantitatively identify the coelomic fluid of Echinometra mathaei as a new source of polyhydroxylatednaphthoquinone (PHNQ) antioxidant pigments. Based on the High Performance liquid chromatography–electrospray mass spectrometry (HPLC-MS) analysis in negative mode, the main quinonoid (PHNQ) pigments were identified and quantified. This study also illustrated the total ion current chromatograms and related mass spectra of Spinochrome A, Spinochrome B, Spinochrome C, and Echinochrome A in CL and SpinochromeC in CFCF samples. The ions at 221, 279, 265 and 263 m/z correspond to the pseudo-molecular [M − H] ions of Spinochrome B, Spinochrome C, Echinochrome A, and Spinochrome A, respectively. These components have previously been noted from the shells and spines of sea urchins but identification of PHNQs pigments in CL and CFCF of E. mathaei using LC-MS was introduced for the first time. The results also showed that, the highest DPPH radical scavenging activity of CFCF (88.12 DPPH% scavenging at 70 μg/mL, IC50 =

High resolution electrospray time-of-flight mass spectrometric analysis was applied as a guiding tool for selection of the chlorine containing fractions by their characteristic clusters of isotopic molecular ion peaks in mass spectra. Twelve target-compounds, chlorinated aromatic glycosides were carried out and identified from the methanolic extract of Hypoxis aurea tubers by chromatographic methods. Hypoxichlorosides A–F (3, 6, 9−12) were found to be undescribed compounds. Curculigine A (1), curculigine B (2), curculigine E (4), curculigine J (5), 2,4,6-trichloro-3-methoxy-5-methylphenyl 1-O-β- d -glucopyranosyl-(1→6)-β- d -glucopyranoside (7) and curculigine C (8) were isolated for the first time from this species. The structure determinations were considered based on the spectroscopic evidence including 1D and 2D NMR experiments.

Phytochemical investigations of Blumea balsamifera branches and leaves led to the isolation of ten secondary metabolites, including three new compounds, namely, balsamiferine K (1) and balsamiferosides A (2) and B (3). Structural elucidation was confirmed by detailed analysis of the 1D and 2D NMR spectra as well as HR-ESI-QTOF mass spectra. Among the isolated compounds, blumeaene J (4) exhibited moderate cytotoxicity against LNCaP (IC50 = 44.53 ± 4.95 μM) and SK-Mel2 (IC50 = 46.49 ± 3.84 μM) cell lines and weak effects on HepG2 (IC50 = 61.54 ± 2.98 μM), KB (IC50 = 65.40 ± 4.97 μM), and MCF-7 (IC50 = 70.06 ± 5.65 μM) cell lines, whereas (―)-angelicoidenol 2-O-β- d -glucopyranoside (6) revealed weak activity on all five tested cancer cell lines, with IC50 values ranging from 61.60 ± 5.64–98.73 ± 2.24 μM.

Affinity selection mass spectrometry (MS) or, simply, affinity mass spectrometry (AMS) is a label-free technology that has been used to identify high-affinity ligands of target proteins of interest by screening against small-molecule compound libraries and identifying molecules that are enriched in the presence of the target protein. We have previously applied Agilent Technology's (Santa Clara, CA) RapidFire solid-phase extraction (SPE)-based high-throughput MS technology to screen small-molecule libraries using AMS. However, SPE-based technologies rely on fluidics for desalting and separation prior to mass analysis with attendant high solvent consumption, relatively high sample volume requirements, risk of sample carryover, and frequent maintenance. To address these challenges, we have established an AMS platform using a laser diode thermal desorption-atmospheric pressure chemical ionization (LDTD-APCI) ionization source (Phytronix, Quebec, Canada) coupled with a SCIEX 5600+ TripleTOF MS (Framingham, MA). We also validated a data-independent acquisition (DIA) Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) method for the robust detection and analysis of small-molecule affinity hits. An informatics platform developed in-house has resulted in a streamlined data analysis workflow for high-throughput AMS screening campaigns and reduced data processing time without compromising data quality. Finally, 68,000 compounds were screened in a single plate and affinity selected hits were confirmed in an orthogonal enzyme activity assay.

The pyrolytic reactions of n-propyl and i-propyl radicals and their precursors have been investigated at elevated temperatures and pressures (600–900 K and 5–8 bar). The studies were performed in a miniature high repetition rate shock tube with synchrotron vacuum ultraviolet photoionization mass spectrometry yielding comprehensive datasets of temporal and photoionization energy dependencies of reagents and products. The propyl radicals were generated by pyrolysis of alkyl nitrites. In addition to the main decomposition path, NO elimination, the mass spectra allowed an alternative minor path via HNO elimination to be identified and quantified. For the n-propyl precursor the HNO elimination route accounted for 9% of the alkyl nitrite while for the i-propyl precursor it was 2.5%. These values are in good agreement with a recent study on i-butyl radicals in the same apparatus at similar conditions. The ratio of disproportionation/recombination was obtained for n-propyl from the relative concentrations of n-hexane and propene and for i-propyl from 2,3-dimethyl butane and propene. For n-propyl the ratio is 0.3 and 1.2 for i-propyl, both are independent of temperature and pressure over the experimental range. The disproportionation/recombination ratios are about a factor of 2 higher than prior evaluations that are based mainly on room temperature data. The experimental results are some of the first from the apparatus used and comments are made about the technique, challenges encountered, and suggestions for future developments.

The research included the use of new Schiff's bases to prepare novel mercury (II) complexes as follows: Schiff's bases ligands prepared using aromatic aldehydes and various aromatic primary amines [S1-S6]. Six mercury complexes [H1-H6] were prepared by the interaction of mild moles of organic Schiff's bases with 1 mol of mercury salt (CH3COO)2Hg. The Schiff's bases prepared spectroscopes were diagnosed by the UV–visible spectrum, the infrared spectrum (FT-IR), and the nuclear magnetic resonance spectrum (1H NMR). The reaction mechanism was proposed in light of these results, as it confirmed the validity of the proposed chemical compositions. Metallic complexes prepared spectrally were diagnosed by the UV–visible spectrum, the infrared spectrum and the mass spectrum (Lc-Mass), and analysis of the elements C.H.N.S. The mechanism of interaction was suggested in light of these results, as it confirmed the validity of the proposed chemical compositions, magnetic and electrical conductivity sensitivity of all the prepared complexes was measured. Lc-Mass spectrum results, analysis of the elements C.H.N.S, measurement of molar conductivity, magnetic moment measurements have proven that azomethine compounds interacting with cadmium chloride and mercury acetate are di ligand.

This paper uses a Kinetic Monte Carlo model that includes processes to integrate curvature due to the formation of five- and seven-member rings to simulate polycyclic aromatic hydrocarbons (PAHs) growing in lightly sooting ethylene and acetylene counterflow diffusion flames. The model includes new processes to form seven-member rings via hydrogen-abstraction-acetylene-addition and bay closure reactions on sites containing partially embedded five-member rings. The model additionally includes bay closure and HACA bay capping reactions for the integration of five-member rings. The mass spectra of PAHs predicted by the model are assessed against experimental data, and the distribution of embedded five-member rings and seven-member rings is studied as a function of spatial location, molecule size and frequency of events sampled in the simulation. The simulations show that the formation of seven-member rings and the embedding of five-member rings is a competitive process. Both types of rings are observed more frequently as the simulation proceeds from the fuel outlet towards the stagnation plane. Approximately 15% of the events that integrate curvature resulted in the formation of a seven-member ring coupled to an embedded five-member ring, and the remaining 85% of events embedded five-member rings via the formation of six-member rings. The proportion of PAHs containing embedded five-member rings and/or seven-member rings is observed to be a function of PAH size, passing through a maximum for PAHs containing 15–20 six-member rings. However, the proportion of PAHs containing both types of ring increases with PAH size, where upwards of 10% of PAHs containing at least one five-member ring and 15 or more six-member rings also contain a seven-member ring.

The ion source combining laser ablation of solid targets in helium gas and an RF ion guide system with an RF carpet was constructed for a reference measurement of isotope shifts. It is important for performing planned collinear laser spectroscopy of RI beams from the SLOWRI facility at RIKEN, especially for medium-mass nuclei of refractory elements. They are difficult to produce via the ISOL method owing to the chemical properties of the elements. The laser-ablated ions of Ni, Zr, Ag, Ta, W, and Ba were transported by the ion guide and mass spectra consistent with the natural abundance were successfully observed corresponding to 105–107 ions per laser pulse.

Human serum albumin (HSA) is the most abundant protein in human plasma and plays versatile biological role. HSA has been widely used to treat several diseases and develop biocompatible biomaterials for biomedical applications. However, pharmaceutical-grade HSA (p-HSA) showed the altered oxidative and ligand-binding properties compare to native HSA. To investigate the influences of the manufacturing process on the molecular state of HSA, we determined the first crystal structure of p-HSA using the commercial HSA solution without any defatting step and further purification and carried out mass spectrometry to identify bound ligands. The crystal structure of p-HSA revealed that medium- and long-chain fatty acids and tryptophan are bound to p-HSA and one free cysteine is oxidized to cysteine-sulfenic acid. The mass spectra of p-HSA also confirmed the existence of fatty acids and tryptophan in p-HSA. Our results enhance understanding of the molecular state of p-HSA and can be utilized to produce p-HSA solutions and HSA-based biomaterials that has a higher biorelevance.

Pyrolysis and low-temperature oxidation of dimethoxymethane (methylal, MeOCH2OMe) play an important role in the ignition of blended diesel fuels, but the underlying mechanisms are still debated. In these kinetic models, bimolecular hydrogen abstraction or unimolecular C–O bond fission are considered as the primary initial steps, while MeOCH2OMe isomerization is sometimes disregarded. In this work, we investigate the pyrolysis of MeOCH2OMe combining imaging photoelectron photoion coincidence spectroscopy with vacuum ultraviolet (VUV) synchrotron radiation and CBS-QB3 theoretical calculations to unveil reaction paths and energetics. In the mass spectrum of MeOCH2OMe, pyrolysis products and radical intermediates were observed at m/z 15 (CH3), 28 (CO), 29 (HCO), 30 (H2CO), 31 (CH2OH), 32 (CH3OH), 45 (CH3OCH2), and 75 (H-loss from methylal). Only the m/z 45 and 75 ions are found to be dissociative photoionization products of MeOCH2OMe, the other mass spectral peaks are attributed to ionization of the neutral MeOCH2OMe pyrolysis products. The m/z 31 peak was assigned to the methoxy radical in the previous studies. However, our photoion mass-selected threshold photoelectron spectrum (ms-TPES) confirms that it originates from dissociative photoionization of the primary pyrolysis fragment methanol. Based on the experimental and computational results, a thermal decomposition mechanism of MeOCH2OMe is proposed. Here, H-migration precedes the production of methoxymethylene (CH3OCH) and methanol, while dimethyl ether and formaldehyde are probably formed in multi-step processes, too. The sequential dissociation of CH3OCH and of dimethyl ether yields enhanced m/z 15, 28 and 29 signals at high temperature. Rate constants have been calculated to confirm the dominant role of MeOCH2OMe isomerization and to help improve predictive combustion models.

A dipodal fluorescent probe 3, with imine and hydroxyl moieties as binding sites, has been synthesized and characterized with spectroscopic methods, single-crystal X-ray techniques, and DFT. The synthesized probe 3 (φ = 0.0028) showed highly sensitive and highly specific fluorescent ‘turn-on’ effect (λem = 453 nm) for the 1:1 binding with Fe3+ ions to form probe 3.Fe3+ complex (φ = 0.203) in semi-aqueous medium (acetonitrile:water (50:50; v/v)) and live cells. The 1:1 binding stoichiometry of probe 3 and Fe3+ ions was proposed by DFT calculations and confirmed by the NMR spectroscopy, crystal structures of probe 3 and 3.Fe3+ complex, and mass spectrum of probe 3.Fe3+ complex. The stability of probe 3.Fe3+ complex in a wide pH range (pH 2–12) and reversibility for binding with Fe3+ ions in the presence of EDTA indicates that it can be an effective chemosensor for the detection of Fe3+ ions in various samples, including living cells. Importantly, with the LOD of 21.5 nM for the detection of Fe3+ ions, probe 3 did not show any interference from potentially competing ions even at a 1:3 ratio, indicates its biocompatibility. The nanomolar limit of detection (21.5 nM), cell permeability, and low cytotoxicity allows the probe 3 to be an excellent tool for the live-cell imaging and detection of ferric ions in live cells.

The ethanol decomposition process for hydrogen-rich gas synthesis via microwave discharge in ethanol-water mixtures was investigated in this study. Excited active species and gas-phase products based on ethanol’s varying volume fraction were detected via optical emission spectroscopy (OES) and mass spectrometry (MS). The correlation between the spectrum signal of the active species and the mass spectrum signal of the gas phase products was quantitatively analyzed. The experimental results showed that the intermediate active species mainly consisted of OH, C2, CH2, CH, C, and H, and the gas phase products mainly included H2, CH4, C2H2, CO, C2H4, and CO2. There were significantly positive linear relationships between H or CH2 and H2, demonstrating that both H and CH2 were important radicals for generating H2. Based on the experimental results and analyzed from the perspective of thermodynamics, the reactions of H + H (+M) → H2 (+M) and H + H + H2→H2 + H2, H + H + H2O → H2 + H2O, CH2 + CH2→ H2 + C2H2 were all likely to produce hydrogen.

In this study, the evolution characteristics of sulfur-containing gases during thermal conversion of two coals under different atmospheres were studied through temperature-program decomposition (TPD) and rapid-heating decomposition (RHD) coupled with online mass spectrum (MS). The releasing profiles of H2, CH4 and CO were also measured. Results showed that the effect of atmosphere and heating rate on evolution of sulfur-containing gases was very significant. It was found that Ar atmosphere was more favorable to the formation of sulfur-containing gases than CO2 atmosphere by using TPD-MS. In CO2, the formation of H2S and SO2 was restrained in 260–650 °C, but was promoted in 880–980 °C; the formation of COS was promoted during the whole process. In Ar, high releasing intensity of H2 and CH4 could stabilize sulfur-containing radicals which led to high amount of H2S and SO2; while high releasing intensity of CO in CO2 resulted in high amount of COS. By using RHD-MS, it was found that the steam atmosphere was highly favorable for the transformation of H2S, SO2 and COS during the entire reaction period. However, the CO2 atmosphere was disadvantageous to the transformation of H2S, SO2 and COS at the initial stage, but slight favorable for the transformation of H2S, SO2 and COS during the later stage. These was resulted from the gasification reaction of steam/CO2 with coal. The key factor was the releasing amount of H2 and CO, which promoted the formation and transformation of H2S, SO2 and COS.

We have designed and synthesized a new luminescent mononuclear samarium (III) complex Sm-2h based on the [1 + 1] Schiff-base macrocycle H2L2h, derived from the cyclocondensation reaction between dialdehyde and diamine precursors, and its exact architecture is determined to be [Sm(HL2h) (NO3)2]. The sensing ability of complex Sm-2h is carefully evaluated for various common inorganic ions in solution. It is shown that complex Sm-2h is a multi-responsive fluorimetric sensor with high selectivity for F− and PO43− anions together with Zn2+ cation. The sensing process is rapid within 60 s for F− and PO43− ions and 300 s for Zn2+ ion. Further detailed responsive investigations suggest that its sensing behavior has excellent linear relationship between the fluorescence intensity (or absorption value) and ion concentration. The limit of detection (LOD) for sensing F−, PO43− and Zn2+ ions are as low as 2.61 μM (2.94 μM), 1.92 μM (1.64 μM) and 5.67 μM (3.53 μM), respectively, verified by fluorimetric (or colorimetric) titration experiments. ESI mass spectra prove that these efficient detections originate from the structure collapse of sensor Sm-2h because of the ion-induced imine bond breakage. Moreover, sensor Sm-2h shows excellent sensing performances for F−, PO43− and Zn2+ ions in real water samples, and we also have developed a convenient method to detect these three ions by use of the sensor impregnated test paper strips, providing rapid and distinguishable fluorimetric color changes. Therefore, the macrocyclic Sm(III) complex Sm-2h could be regarded as a valuable candidate for monitoring F−, PO43− and Zn2+ ions in practical applications.

We describe the use of MALDI-TOF mass spectrometry in the analysis of a suspected case of gamma heavy chain disease. The patient had an abnormal serum immunofixation result where a monoclonal gamma heavy chain band was present without a corresponding light chain. Analysis by MALDI-TOF mass spectrometry revealed large peaks in the spectrum following IgG-specific purification. The m/z values of the peaks were outside the expected range for normal heavy chains or light chains. Corresponding peaks were not present in mass spectra of the kappa- or lambda-specific purifications. MALDI-TOF MS confirmed the presence of a truncated heavy chain without associated light chains. This case report demonstrates the value of mass spectrometry in interpreting challenging cases such as the identification of heavy chain disease.

Various dyes present in historical objects can be indicative of different usage, age and origin of the artifacts. Knowledge about the composition and origin of textile dyes is essential for the preservation and conservation of the items. In this paper, we compare different instrumental techniques to detect and identify natural red dyes from historical textiles without the need for standard substances of the dye components. Several instrumental techniques were used, including liquid chromatography with photodiode array, fluorescence and mass-spectrometric detectors, as well as Fourier transform ion cyclotron resonance mass spectrometry with electrospray ionization and matrix-assisted laser desorption/ionization sources. Seven natural red dye sources were investigated, including dyer's madder, redwood, logwood, sandalwood, kermes, American cochineal and bloodred webcap (Cortinarius sanguineus). The dye components of the latter source have not been characterized before with all of these analytical techniques. A substantial library of chromatograms and mass spectra, along with absorption and fluorescence spectra (altogether 113 chromatograms/spectra), of dyes and/or dye components were recorded and a comparison of the utility of the different analytical techniques in the analysis of the dye sources is provided. The usefulness of the assembled library of chromatograms/spectra is demonstrated on the analysis of several historical textile samples from museum artifacts.

Mass spectral data from multiple samples are suitable for a hypothesis-free development of clinically useful multivariate tests using modern machine learning techniques. However, the transition from discovery to adoption of proteomic tests has proved challenging. Slow adoption of these tests in clinical practice is, in part, related to insufficient understanding of the biological mechanisms underlying multivariate tests developed based on correlative studies. While identification of individual proteins may provide important insights, elucidation of concerted relationships of sets of proteins with biological pathways can better reflect complex phenomena, such as cancerogenesis and response to treatment. Protein set enrichment analysis (PSEA) allows identification of associations of mass spectral features or test classifications with biological function by looking for consistent correlations across a group of proteins. We evaluated the utility of PSEA for exploring the biological information content of mass spectra, using a sample set with mass spectral data and matched protein expression information. This made it possible to detect significant biological associations with mass spectral peaks without identifying their protein constituents. We demonstrated that the method produces reproducible associations and can be used for elucidation of the mechanisms of action associated with two previously developed multivariate mass spectrometry-based tests. Significant correlations with several host immune response-related processes were found on the level of individual mass spectral features and with test classifications. The results illustrate the utility of the PSEA approach applied to mass spectral data as a method for elucidating biological mechanisms underlying phenotypes related to different physiological states of the organism.

Gasoline is a mixture of hydrocarbon components. The hydrocarbon components are characterized by parameter like density and boiling point. Gas chromatography together with mass spectra software called piona which give a valuable data’s for quality detection and environmental issues. This GC-PIONA gives RON and MON informative data’s individually as well as collectively for adulteration purpose.

Secondary organic aerosol (SOA) can influence the radiative balance of the atmosphere via its optical properties. The single-scattering albedo (SSA) and complex refractive index (RI) are the basic optical parameters of the aerosol particles. Toluene SOA particles were formation and aging with extreme amounts of OH radicals without NOx in flow reactor chamber in this study, cavity-enhanced aerosol single-scattering albedometer, UV–Vis spectrometer, and liquid chromatography-mass spectrometry (LC-MS) were utilized to measure the optical properties and components of the aged toluene SOA, respectively. Experimental results demonstrated that the retrieved real part of RI for aged toluene SOA was 1.452 ± 0.002, which is consistent with the reported data. The measured SSA of aged toluene SOA was 0.78 ± 0.02, slightly lower than that of organic aerosols associated with biomass burning (BBOA), and the k-value (imaginary part of RI, corresponding to the absorption extent of SOA particles) was 0.024 ± 0.002, larger than that of fresh toluene SOA, indicating that the absorbing ability of SOA increased with increasing oxidation level. The obtained UV absorption and electrospray ionization mass spectrum shown that carboxylic acids are identified as the principal constituents of aged toluene SOA, which are responsible for the decreased SSA and increased k-value measured by the albedometer when compared to the fresh SOA. As the rate of production of SOA is greater than that of BBOA, the aged SOA particles may contribute remarkably to the radiative balance of the atmosphere. These would provide experimental basis for refine the radiative forcing estimates of anthropogenic SOA for certain regions.

This article presents the chemical analysis of jet fuel (Jet A-1) heteroatomic components generated as a result of thermal stressing. Jet A-1 was thermally stressed by flow and static tests in a single tube heat exchanger in the autoxidation regime (150 to 300 0 C). Jet A-1 samples were analyzed by electrospray ion mass spectrometry (ESI-MS), Fourier transform infrared (FTIR) and 13C nuclear magnetic resonance (NMR) spectroscopy. Mass spectra of Jet A-1 recorded higher molecular weight components in the mass range 300-1000 Da. FTIR spectra revealed absorption bands for oxygen-containing species such as alcohol, phenol, and ether. Jet A-1 NMR spectra recorded heteroatomic alkoxy species. A lichen substance, gyrophoric acid was identified as Jet A-1 component. ESI-MS, FTIR and NMR spectra of unstressed jet fuel recorded peaks corresponding with gyrophoric acid. Natural products polyphenols and lichen derived compounds are excellent antioxidants, and their advantages as potential fuel additives are discussed.

A new benzyls pendant-armed macrobicyclic heterbinuclear Cu(Ⅱ)-Ni(Ⅱ) complex has been obtained by template-directed synthesis and characterized by elemental analysis, IR spectra, electrospray mass spectra, and single crystal X-ray diffraction. The complex was bridged by two phenolic oxygens and an acetate radical, with the Cu(Ⅱ)-Ni(Ⅱ) distance of 2.9292(8) A. The hydrolytic function, CT-DNA binding and antibacterial properties were also studied. The initial rate values for the hydrolysis of 4-nitophenylphosphate to 4-nitrophenolate by the Cu(Ⅱ)-Ni(Ⅱ) complex was 1.33 × 10−5 s−1, and 104 times faster than that the spontaneous hydrolysis of the phosphate monoester. The complex shows a better binding property to CT-DNA and the intrinsic binding constant is 1.29 × 105 M−1. The Stern-Volmer constant is 1.25 × 105 M−1. The viscosity increased obviously with the increase of complex concentration, the results showed that the complex bind to DNA through intercalation mode, which was in accordance with the absorption and emission spectral studies. The antibacterial activities against E.coli was also investigated using the Gentamycinas reference system.

A rhodamine B-based chromo-fluorogenic probe BOS is prepared with a good yield by condensating an o-diaminobenzene functionalized rhodamine derivative (RBO) and a large steric hindrance salicylaldehyde, and characterized by elemental analysis, infrared spectroscopy (IR), 1H and 13C NMR technology, and high resolution mass spectrum (HRMS). Spectroscopy experiments reveal that the probe can selectively and sensitively detect Al3+ from a variety of metal ions with a low detection limit of 1.855 μmol/L. Compared to traditional detection methods, BOS provides an inexpensive, rapid and straightforward way for Al3+ detection that can be distinguished by “naked eye”. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2-H- tetrazoliubromide) assays and cell imaging experiments demonstrate that the sensor is low toxic and amicable for Al3+ sensing in living cells.

In this paper, we present the synthesis and tribological properties of two naphthatate-based lubricating oils. The structure and purity of the oils were analyzed using nuclear magnetic resonance spectra and high resolution mass spectra. Their thermal and oxidation stability, flash point and pour point, viscosity and viscosity index, and friction reduction and anti-wear properties were also tested. In the results, the two isooctyl naphthatate-based oils (INA) displayed better lubricating properties than a reference sample of isooctyl sebacate (ISE) on three different friction pairs. The new oils also offered higher oxidation stability than the reference sample. It was found that the stability and lubrication properties of ester-based lubricating oils can be significantly improved by introducing a naphthalene ring into the molecular structure. This is because there is a large π-electron conjugate system on the naphthalene ring, which not only reduces the likelihood of an oxidation chain reaction, but also enables the oil to form an orderly and stable lubricating film on metal surfaces. One of the oils, 2,3-INA, was found have better oxidation stability than the other one, 1,4-INA, because its oxidized groups are positively affected by the steric and conjugation effects of the two ester groups.

Polyfluorinated dibenzo-p-dioxins (PFDDs) are dioxin compounds that have been detected in industrial fluoroaromatic chemicals and can cause adverse effects to organisms. In this work, the photochemical behaviors of PFDDs congeners on silica was systematically investigated. The pseudo-first-order rate constants (k, h−1) of surface photolysis changed with the substitution number and position of fluorine atoms, and the tetra-fluorinated PFDDs tended to degrade more efficiently. Octafluorinated dibenzo-p-dioxin (OFDD) was selected as a representative to explore the reaction mechanisms. Product analysis showed that OFDD was decomposed into hydroxylated PFDDs (OH-PFDDs) and hydroxylated polyfluorinated diphenyl ethers (OH-PFDEs) via hydroxyl substitution and ( OH radical mediated or direct) C–O bond cleavage. Coupling elimination reaction was also observed, resulting in the formation of three-membered and four-membered ring compounds. According to the extracted peak areas in mass spectra and the energy barrier in potential energy surface, direct homolysis of C–O bond occurs as the dominant reaction pathway. This work could provide some new insights into the environmental fate of dioxin compounds.

The ubiquity and potential toxicity of phthalates make their exposure on humans a matter of great concern. Measuring the targeted phthalate metabolites using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a commonly used approach for human biomonitoring of phthalates. However, the targeted LC-MS/MS methods have been unable to meet the desire to comprehensively and rapidly screen and identify for as many known and potentially unknown phthalate metabolites in human samples. Instead, non-targeted screening methods, allowing the rapid detection and identification of unknown compounds in a wide variety of environmental and human samples are complementary to the targeted methods. In this study, 23 phthalate metabolites were analyzed using liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) for development of a non-targeted screening method. The fragmentation patterns of the 23 phthalate metabolites were investigated using collision-induced dissociation experiments at 10, 20, and 40 eV. And three common specific product ions at m/z 121.0297, m/z 147.0088, and m/z 165.0193 corresponding to C7H5O2-, C8H3O3-, and C8H5O4-, respectively were observed in their mass spectra. Based on the three common product ions, a new strategy was proposed for non-targeted screening of the new phthalate metabolites as exposure biomarkers for human biomonitoring. It can greatly reduce the time spent on data processing for potential precursor ions. Additionally, the correlation of the retention time and logKow of the phthalate metabolites was explored, which provides a useful tool to reduce the number of identified candidates in the non-targeted screening.

Gas chromatography–mass spectrometry (GC MS) has been extensively used in complex sample analysis for the high-throughput characterization of volatile and semivolatile compounds. However, the accurate extraction of compound information remains challenging. Here, we present a combined algorithm strategy for GC MS data analysis to accurately screen metabolites across groups. First, chromatographic peaks in a total ion chromatogram (TIC) are extracted by using a Gaussian smoothing strategy and aligned on the basis of their mass spectra by a dynamic programing algorithm. The aligned TIC peaks are then registered into a component list table by applying a nearest-neighbor clustering algorithm. Significantly expressed TIC peaks among groups are screened through statistical analysis, such as ANOVA. Second, a chemometric method of multivariate curve resolution–alternating least squares for the peak resolution of the screened TIC peaks is utilized to retrieve the chromatographic and mass spectral profiles of coeluted components. The developed strategy is employed for the analysis of standard and complex plant sample datasets. Results indicate that our methodology is comparable with several state-of-the-art methods that are widely used in GC–MS-based metabolomics.

Variable-temperature nano-electrospray ionization coupled with ion mobility spectrometry-mass spectrometry is used to investigate the thermal denaturation of the tetrameric protein concanavalin A. As the solution temperature is increased, changes in mass spectra and collision cross section distributions provide evidence for discrete structural changes that occur at temperatures that are ~40 to 50 degrees below the temperature required for tetramer dissociation. The subtle structural changes are associated with four distinct tetramer conformations with unique melting temperatures. Gibbs-Helmholtz analysis of the free energies determined with respect to the most abundant “native” state yields heat capacities of ΔC(p) = 1.6 ± 0.3, −2.2 ± 0.4, and −2.9 ± 1.6 kJ·K(−1)·mol(−1), and temperature dependent enthalpies and entropies for the three non-native conformations. Analysis of the thermochemistry indicates that the high-temperature products are entropically stable until the threshold for tetramer dissociation, and changes in heat capacity are consistent with increases in solvation of polar residues. Our findings suggest these high-temperature non-native states result from an increase in disorder at surface exposed regions. Such studies provide valuable insight towards the structural details of non-native states.

Graphical abstract, Highlights • MALDI-TOF MS is applicable as high-resolution and high-throughput tool. • The classification and characterization of cultivable microorganisms is targeted. • Advantageous are its simple sample preparation and short measurement time. • It accelerates the dereplication of isolates from large-scale screening campaigns. • Applications for studying microbial diversity and future trends are discussed., Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) has become one of the most popular methods for the rapid, cost-effective and accurate classification and characterization of cultivable microorganisms. Due to its simple sample preparation and short measurement time, MALDI-TOF MS is an excellent choice for the high-throughput study of microbial isolates from rhizospheres or plants grown under diverse environmental conditions. While clinical isolates have a higher identification rate than environmental isolates due to the focus of commercial mass spectral libraries on the former, no identification is necessary in the dereplication step of large environmental studies. The grouping of large sets of isolates according to their intact protein profiles can be performed without knowledge of their taxonomy. Thus, this method is easily applicable to environmental samples containing microorganisms from yet undescribed phylogenetic origins. The main strategies applied to achieve effective dereplication are, first, expanding existing mass spectral libraries and, second, using an additional statistical analysis step to group measured mass spectra and identify unique isolates. In this review, these aspects are addressed. It closes with a prospective view on how MALDI-TOF MS-based microbial characterisation can accelerate the exploitation of plant-associated microbiota.

Lotus plumule, a traditional Chinese medicine, has significant pharmaceutical value to treat various health problems. Flavonoids are important bioactive ingredients in lotus plumule. In this study, we proposed an efficient "fishing" strategy to profile and identify non-targeted flavonoids from lotus plumule aqueous extract based on a self-built mass data "pool" with an untargeted mass data acquisition method in order to acquire comprehensive structural information of flavonoids in lotus plumule. This mass data acquisition method was applied by ultra-high performance liquid chromatography coupled with hybrid quadrupole orbitrap high-resolution mass spectrometry (UHPLC/Q-orbitrap HRMS) executed in full MS/dd-MS2 mode with different collision energies in positive ionization mode. The self-built targeted data "pool" was constructed by the basic structure of flavonoids in lotus plumule, such as odd quasi-molecular ions, C6-C3-C6 skeleton, molecular weight limit. The "molecule lures" of fishing are characterized by molecular features, fragmental patterns, characteristic fragments ions, relative abundance and retention times. More importantly, the special "lures" of PredRet (the tool of predicting the retention times) and ClogP (the calculated lipophilicity parameter) were adopted to distinguish some isomers and some compounds whose mass spectra are difficult to determine with no reference substances. The "fished" flavonoids were further confirmed by their molecular features and fragmental patterns. This developed analysis method was successfully applied to profile 29 flavonoids compounds in the aqueous extract of lotus plumule, and 3 of them were recognized for the first time in lotus plumule. To our knowledge, this is the first analytical screening methods without standard samples to systematically identify flavonoids in lotus plumule.

Triacetone triperoxide is one of the most common used explosives by terrorist and criminal groups, being easily synthesized with over the counter reagents. Moreover, it’s difficult to detect since it contains no nitrogen. Extreme resolution mass spectrometry, based on Fourier transform ion cyclotron resonance mass spectrometry provides a way to established its composition, being able to detect its presence in complex matrixes. In this work, we investigated the detailed chemical composition of triacetone triperoxide and analysed latent fingerprints for evidence of its handling. Our results allowed the characterization of the oligoperoxides formed in the synthesis of triacetone triperoxide: oligomers dihydroperoxy terminated [H(OOC(CH3)2)nOOH] and the oligomeric acetone carbonyl oxides terminated as hydroperoxides [H(O2C(CH3)2)nOOC(O)CH3]. The discrimination between the different synthetic routes using different acid catalysts is possible given the clear differences between the mass spectrum corresponding to each case. Moreover, we identified triacetone triperoxide in latent fingerprints following its manipulation. For criminal investigation, in addition to the unambiguous detection and identification of the explosive, it is of the highest interest to identify the reagents used, who produced it and who used it for criminal purposes.

A Chinese herbal formula of Anti-Renal Interstitial Fibrosis I Decoction (ARIF I) is composed of Eucommia ulmoides Oliv., Scutellaria baicalensis Georgi, and Rheum. officinale Baill., and it has been used for the treatment of chronic kidney disease for many years. However, the comprehensive chemical analysis of the formulated ARIF I has yet to be clarified. In this study, an ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap high resolution mass spectrometry (UHPLC/Q-orbitrap HRMS) method executed in full scan/data-dependent MS2 (full MS/dd-MS2) mode has been established in negative ion mode to analyze the major chemical constituents in ARIF I as well as in its three constituent herbs. To rapidly and efficient identify these compounds, we employed a combination of statistical analysis of the MS2 data and fragmentation pathway method to screen for elementary characteristic ions and sub-characteristic ions. Then, we applied multifold characteristic ion filtering to comprehensively profile ARIF I extract chemical constituents with diverse structures. A total of 360 compounds, including anthraquinones, sennosides, galloyl glucoside derivatives, catechin and its derivatives, flavonoids, iridoids, phenylpropanoids, lignan, organic acid, and other compounds were rapidly identified or tentatively characterized by multifold characteristic ion filtering based on their accurate mass spectra (within 5 ppm error) and structure types or by comparison with reference standards. All the ARIF I compounds were also detected in the individual constituent herbs. This study provides a basis for further pharmacokinetic studies of ARIF I and may help in the discovery of new chemical drugs to treat chronic kidney disease. This study also provides a more efficient approach for the screening of appropriate characteristic ions, and a practical strategy for the detection of the types of compounds identified in this study in other herbal medicines.

This work highlights the discovered in-situ analytical reaction between primary/secondary alcohols and nitrogenous bases (pyridine, quinoline) that involves the substitution of hydroxyl groups for nitrogen-containing charged species and proceeds in an ionization region of Direct Analysis in Real Time mass spectrometry (DART-MS) instrument at gas stream temperature of 150–450 °C. Resulted cations provide strong signals in mass spectra and this ensures high sensitivity of the analysis. Collision induced dissociation of such precursor ions gives rise to characteristic and simple fragmentation mass spectra revealing mainly protonated nitrogenous bases and carbonium cations resulting from the elimination of neutral nitrogen-containing bases. The dependence of signal response on gas stream temperature was elucidated. It was also found that, independently of gas stream temperature, high volatility low-molecular weight alcohols did not demonstrate characteristic DART spectra owing to a high rate of desorption/evaporation which does not provide sufficient probability of the reaction. To the best of our knowledge, this type of specific reactions in a plasma-based source of DART mass spectrometer is reported for the first time. It represents a new and interesting derivatization approach providing a rapid and sensitive complement method for the detection and identification of individual monools of various origin, profiling plant sterols and other steroid alcohols in different matrices.

Aluminum is known as the most ubiquitous metal in earth's crust but its excessive exposure will cause damage to environment and health of the organism. Here, a turn-on Schiff base fluorescence probe STH based on excited state intramolecular proton transfer and photoelectron transfer processes for Al3+ detection with fast response rate (within minutes), low detection limit (4.26×10-8M), high selectivity and reasonable pH application range (5.0-8.0) was developed. Fluorescence titration experiments show that probe STH has an excellent linear relationship (R2=0.9694) with Al3+ concentration and could be applied to quantitatively recognize Al3+ in real-water samples. Based on Job's plot and in situ mass spectra, two STH molecules will complex with Al3+ to form 2:1 complexation with oxygen atoms of hydroxyl and carbonyl groups and nitrogen atom of CN bond participating in coordination.

The detailed molecular composition of laboratory-generated secondary organic aerosols (SOA) during the high-NO photooxidation of β-pinene (βP) was investigated using a novel thermal desorption dichloromethane-assisted low-pressure photoionization mass spectrometry (TD-CH2Cl2-assisted LPPI-MS) technique. We found that protonated norpinone gave the highest signal intensity, which supported that assumption that this compound was the key oxidation species responsible for promoting βP-SOA formation. In addition to the previously identified monomers (i.e., 2,2-dimethylcyclobutyl-1,3-dicarboxaldehyde (m/z 140), pinene aldehyde (m/z 150), myrtenol (m/z 152), (2,2-dimethyl-3-acetyl)-cyclobutylformate (m/z 156), pinene acid (m/z 166), and isomers of pinalic-3-acid (m/z 170)), two additional nitrogen-containing species (i.e., C10 hydroxy nitrate and C10 carbonyl nitrate) were also observed at m/z values of 214 and 216 in the mass spectrum of βP-SOA. Furthermore, the losses of 18 (H2O), 46 (NO2), and 64 (H2O + NO2) were attributed to the typical fragmentation pathways of the two nitrogen-containing species. Overall, these results not only contribute to an improved understanding of βP-SOA formation, but they also indicate that TD-CH2Cl2-assisted LPPI-MS can be used as a novel detection means to study SOA formation.

A novel ratiometric and reversible chemosensor 4-((2-(Benzo[d]thiazol-2-yl)phenyl)ethynyl)-N,N-diethylaniline (BT-1) based on ortho-arylethynyl benzothiazole with large Stokes shift (Δλ≈190 nm) was designed and synthesized to recognize Cu2+. Copper ion induces a remarkable fluorescence enhancement and causes formation of a BT-1-Cu complex. The clamp-on coordination mode of BT-1 to Cu2+ was demonstrated using Job's plot, mass spectrum (MS) and DFT calculations. The calculations also indicate that Cu2+ was chelated to BT-1 through N and alkyne instead of S and alkyne. The probe could quantify Cu2+ with the detection limit of 3.2 × 10−9 M. The in vitro imaging results indicated that the probe BT-1 was membrane-permeable and could be applied into the recognition of Cu2+ ions in living cells.

A novel Schiff-base, [9-(2-Chloro-ethyl)-9H-carbazol-3-yl-methylene]-(9-ethyl-9H-carbazol-3-yl)-amine (CECA) was designed and synthesized, which was highly selective and sensitive for the detection of Al3+ by colorimetric, ultraviolet absorption and fluorescence three-signal methods. The detection limit was evaluated to be as low as 74 nmol/L for the ultraviolet absorption method and 19 nmol/L for fluorometric method. These three methods could determine qualitatively and quantitatively the concentrations of Al3+ and been used in different conditions. The mechanism was explored that the double bond (C N) of CECA was broken to form the carbazole aldehyde and carbazole amine complex accompanied by fluorescence enhancement by the Job's plot, 1H NMR, the electrospray ionization mass spectra (EI-MS) and fluorescence methods. More significantly, the fluorescence imaging showed that CECA could detect Al3+ in living cells.

This work presents the development of chemometric models, based on spectroscopic data, predicting the swelling potentials of aviation fuels towards three ready for use acrylonitrile-butadiene-rubber (NBR) types exhibiting acrylonitrile contents of 18, 28 and 39%. For this purpose quaternary model substance mixtures, containing compounds, which are typical for aviation fuels were prepared. As a second set, exclusively aliphatic synthetic aviation fuels were blended with varying amounts of an aromatic fraction. After immersion in the prepared fluids, the extent of the equilibrium mass uptakes by the elastomers was determined and interpreted in terms of different mixtures’ formulations. UV/Vis- and infrared (IR) spectra were collected of all liquids. Additionally, gas chromatography/mass spectrometry (GC/MS) analyses were carried out. Based on the obtained data, sum mass spectra, which are basically a merging of all recorded mass spectra of a chromatographic run, were generated. Spectroscopic data and swelling characteristics were correlated using partial least squares regression (PLS). Here two different models, based on both training sets were established for each spectroscopic method. Obtained regression coefficients underwent a detailed evaluation to get a better understanding of factors influencing the prediction of swelling potentials. It was found, that they reflect well-known relations between the composition of a liquid, represented by specific spectral information and their corresponding swelling potential. The models were validated by estimating swelling potentials of two commercial jet fuels Jet A-1 and ReadiJet. Infrared spectra pose the most reliable base for the chemometric prediction of swelling characteristics of NBR containing 18% acrylonitrile with prediction errors of 5 and 2% for Jet A-1 and ReadiJet, respectively. Also sum mass spectra allow a relatively accurate estimation.

Samples of elemental copper, upon laser irradiation under negative-ion LDI-MS conditions, do not generate noticeable signals for copper-bearing gaseous ions. In contrast, a several thousand-fold enhancement of the generated ion current was observed when freshly made mixtures of copper and sulfur powders were laser-ablated. Time-of-flight mass spectra recorded showed a range of peaks with m/z ratios extending to over m/z 8000, indicating the formation in situ of an array of Cu–S ion clusters by a chemical reaction that takes place between the two elements upon laser irradiation. Evidently, sulfur acts as a potent reactive matrix and generates at least three distinguishable series of ion clusters: Cu1Sx− (x = 2, 3, 4…), Cu2Sy− (y = 3, 4, 5…), and Cu3Sz− (z = 3, 4, 5…). Laser ablation of CuS alone did not produce signals beyond m/z 600. Some of the high-mass ions formed in this manner were isobaric; consequently, composite peaks were observed under low-resolution MS conditions. Under high-resolution conditions, however, we were able to separate and determine the composition of some isobaric mixtures. For example, the peak recorded at m/z 287 was resolved to two peaks that represented primarily the 63Cu265Cu32S3− and 63Cu32S7− ions. Intriguingly, the spectra recorded from many copper-containing minerals mixed with sulfur were remarkably similar to those acquired from copper-and-sulfur mixtures, which demonstrated that elemental sulfur has the ability to extract chemically bound copper even from its compounds, and form gas-phase Cu–S clusters of varying composition.

The results of mass spectra of d -ribose molecular beam study by electron impact for the 20–70 eV energy range at the evaporation temperature 310–430 K are presented. The experiment was carried out in two stages: first the mass spectra were measured in the range of 0–200 Da at different ionization energies, then relative cross-sections of single ionization of fragment ions were investigated in the electron energy range of 5–60 eV. The measured temperature dependences show the competing character of water and oxonium cation formation processes. It is the first determination of the appearance energy (AE) for the d -ribose molecule from the threshold region of the energy dependence of the effective ionization cross section. For the most intense fragment ions in the mass spectrum, the potentials of appearance are determined at the threshold of the dissociative ionization cross sections. Schemes for the fragmentation of positive d -ribose ions are proposed.

The work was aimed at using gas to cool the secondary ions emitted from gas cluster ion beam (GCIB) bombardment of biosamples for lowering the ion energy distribution and thus enhancing the detection sensitivity for secondary ion mass spectrometry (SIMS). An Ar-cluster ion source at energy in an order of keV was installed with the Q-ToF (Quadrupole Time-of-Flight) premier at the Quantum Science and Engineering Center, Kyoto University. The main component of the Q-ToF premier consisted of a travelling-wave ion guide, a mass filter quadrupole lens, a travelling-wave collision cell, and a ToF analyzer. A 1,2-Distearoyl-sn-glycero-3-phosphocholine (DSPC) sample was used in the study on cooling the secondary ions at the travelling-wave ion guide by using helium and molecular nitrogen gas. The DSPC sample was impinged with primary Ar-cluster ions at energy 10 keV and sputtered for secondary ions in an energy range from zero to several hundred eV. Sputtering-emitted secondary ions were extracted to the Q-ToF mass spectrometer. The experiment was carried out to measure DSPC secondary ion mass spectra in two modes at varied pressures of helium or molecular nitrogen gas. The first mode was the MS mode and the other was the MS/MS mode which defined the m/z = 790.6 Da for the protonated molecule at the mass filter quadrupole lens. The experiment found that the secondary ion yields (SIYs) in the MS mode reached the maximum at 2.0 and 0.35 Pa for helium and molecular nitrogen, respectively. In the MS/MS mode, the SIYs reached the maximum at 2.5 and 0.35 Pa for helium and molecular nitrogen, respectively, and however, some fragments could not be eliminated by the cooling molecular nitrogen gas. The cooling of the secondary ions for lowering the energy distribution and the transverse direction of the secondary ions by using helium was more effective and stable than by using molecular nitrogen.

Fentanyl and its derivatives are amongst the ever-growing list of emerging drugs which are impinging on current traditional analytical techniques employed in forensic laboratories. To avoid current regulations, fentanyl analogues are being illicitly synthesized by slight alterations of functional groups to the fentanyl skeleton leading to inaccurate identifications, thus posing the greatest challenge to laboratories. In this study, a novel analytical technique is presented in which gas chromatography (GC) is interfaced with both cold electron ionization mass spectrometric (cold EI MS) and vacuum ultraviolet (VUV) detection by the means of a flow splitter for the simultaneous qualitative and quantitative analysis of twenty-four fentanyl analogues, including seven sets of positional isomers. For most of the twenty-four analogues, enhanced molecular ions were obtained with at least 1% intensity relative to base peak. In addition to enhanced molecular ions, the GC-cold EI MS maintained fragmentation pathways observed by GC MS with classical electron ionization. For the most part, VUV detection resulted in unique VUV spectra for fentanyl analogues including positional isomers. The combination of these two complementary detectors in tandem with the high resolving power of the gas chromatograph, allows for higher confidence in analyte identification by the combination of retention times, cold EI mass spectra and VUV spectra. The preferred method for quantitation was based on VUV detection and offered excellent determination coefficients (R2≥0.999) for most analytes over two orders of magnitude dynamic range, without the need for deuterated internal standards. For both run-to-run and day-to-day repeatability studies, at moderate solute concentrations, the correct fentanyl related compound was identified in almost every instance from a library containing all the fentanyl analogues plus hundreds of other analytes.

The chemical composition of submicron aerosol particles was characterized using an aerosol chemical speciation monitor (ACSM) at a mixed-mature forest site at the Aukstaitija Integrated Monitoring Station in the eastern part of Lithuania. Four organic aerosol (OA) factors were determined by positive matrix factorization (PMF) analysis applied for the ACSM data: semi-volatile oxygenated OA (SVOOA, the contribution to the total OA mass concentration was 33%), low-volatile oxygenated OA (LVOOA, 39%), cooking related OA (COA, 15%) and biomass burning OA (BBOA, 13%). In our study secondary organic aerosol (SOA) has been identified as one of the most important contributors to the submicron particle (PM1) mass concentration. A comparison between SVOOA and submicron forest organic aerosol mass (SFOM) was performed, and a good correlation of 0.75 between them was found. In our study the SOA concentration dependence on temperature was explored in 3 means: firstly, by investigating aerosol mass spectra measured during hot and cold days. It has been found that during hot days events signal intensities of m/z 42, 43, 45, 53 and 59 were about 2.1–2.7 times higher compared to those during cold days. Secondly, by investigating the temperature dependence of SVOOA and estimated SFOM. It has been found that SFOM and SVOOA concentrations increase with temperature. Thirdly, by assessing the influence of temperature related stomatal conduction on SVOOA concentration: no direct influence on SVOOA concentration was observed.

The determination of the chemical characterization and the order of ink crossing by ballpoint pens have received increasing and important attention in forensic analysis due to forgery or alteration of documents strongly related to their use. The examination of these cases must be using non-destructive methods, in order to preserve the integrity of the evidence present in the documents. Laser desorption ionization mass spectrometry (LDI-MS) and LDI mass spectrometry imaging (LDI-MSI) have been widely applied in forensic document analysis by offering specific information on the chemical composition of the material from the mass to charge ratio (m/z) of the dyes without destroying the spatial location of the analytes. In this work, the combination of LDI data with statistical treatment, such as principal components analysis, classified the blue and black pen inks according to their 11 brands and 18 models studied. The interpretation of the LDI mass spectra allowed a chemical profile analysis relating the concept of relative ion intensity of the following dyes: methyl violet (m/z 372), ethyl violet (m/z 456), basic blue 26 (m/z 470), and basic blue 7 (m/z 478). In addition, the order of ink crossing (pen over pen, pen over printer and vice versa) was determined by monitoring the ions: methyl violet dye (m/z 372), their homologues (m/z 358, 344, 330, 316) and basic blue 7 (m/z 478) for the pens; and the ions of m/z 285 and 355, for inkjet and laserjet printers, respectively, by the LDI (+) MSI.

Walnut (Juglans regia L.) is an abundant source of polyphenols. Although phenolic species in the walnut kernel have been studied comprehensively, their compositional profile in the internal fruit septum, a traditional nutraceutical material in China, has been rarely explored. In the current study, the methanolic extract of the walnut septum was analysed by Ultra-performance liquid chromatography coupled with Orbitrap mass spectrometry. Totally seventy-five phenolics belonging to flavonoids, tannins and phenolic acids were identified based on mass spectra, references and literatures. Among them, quercetin-3-O-galactoside, quercetin-rhamnose-pentoside, quercetin-3-O-glucoside, quercetin-rhamnose-hexoside, kaempferol-rhamnoside, and two isomers of quercetin-rhamnoside were reported for the first time in walnut. The total polyphenol content was found to be 122.78 ± 2.55 mg GAE/g dry weight in septum. This study is the first to comprehensively investigate and identify phenolic compounds in the fruit septum of walnut and indicates that the septum to be a rich resource of polyphenols.

Ciprofloxacin (CIP) is a broad spectrum synthetic antibiotic drug of fluoroquinolones class. CIP can act as a bidentate ligand forming iron complexes during its degradation in the photo-Fenton process (PFP). This work investigates on PFP for the degradation of CIP to understand the formation mechanism and stability of iron complexes under ultraviolet (UV)-light illumination. A comparison was made with the UV-photocatalysis (UV/TiO2) process where CIP doesn't form a complex. In PFP, the optimal dose of Fe2+ and H2O2 were found to be 1.25 and 10 mmol/L with pH of 3.5. An optimal TiO2 dose of 1.25 g/L was determined in the UV/TiO2 process. Maximum CIP removal and mineralization efficiency of 93.1% and 47.3% were obtained in PFP against 69.7% and 27.6% in the UV/TiO2 process. The mass spectra could identify seventeen intermediate products including iron-CIP complexes in PFP, and only seven intermediate products were found in the UV/TiO2 process with a majority of common products in both the processes. The proposed mechanism supported by the mass spectra bridged the routes of CIP cleavage in the PFP and UV/TiO2 process, and the decomposition pathway of Fe3+-CIP chelate complexes in PFP was also elucidated. Both in PFP and UV/TiO2 processes, the target site of HO• radical attack was the secondary-N atom present in the piperazine ring of the CIP molecule. The death of Escherichia coli bacteria was 55.7% and 66.8% in comparison to the control media after 45 min of treatment in PFP and UV/TiO2 process, respectively.

We demonstrated the use of surface modified zinc oxide nanorod (ZnO NR) array chip for on-plate detection, pre-concentration, separation and subsequently matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) analysis for bacteria present in nanoliter liquid droplet. The surface modified ZnO NR array can be easily fabricated on Zn foil via chemical method. To explore the potential of the fabricated ZnO NR array chip as a MALDI-MS chip and substrate, standard proteins were studied. It was observed that surface modified ZnO NR array substrates provides significant enhancement on analyte ionization in comparison to the conventional MALDI target plate and efficiently suppress the background noises. This significantly leads to clean mass spectra with high resolution and excellent signal intensity. Furthermore, the proposed method was demonstrated for the analysis of bacteria in nanoliter droplets with high reproducibility and it can be further employed as an effective affinity probe to detect and separate the bacteria from sea water and urine. The lowest detectable concentration of the bacteria cells is 1.9 × 102 cfu μL−1 and the minimum volume required for the sample analysis is 50 nano-liter (nL). We believe that this multiple function biochip can serve as an effective bacteria detecting platform in the near future.

Sodium and potassium carbonates are important components of high temperature materials. Therefore, information on gas phase is important for modelling of long term processes, where the stability of carbonates should be taken into account. In this study the vaporization behavior of Na2CO3 and K2CO3 has been studied with Knudsen Effusion Mass Spectrometry in the temperature range from 600 to 880 °C. It was established, that vaporization of sodium and potassium carbonates is close to congruent conditions at temperatures below 750 °C with the main species M, CO2 and O2 in the gas phase. The vapor pressures of these species are in a good agreement with the calculated values within an error of ± 30%, which are based on the available thermodynamic information including formation enthalpies of M2CO3(s) and M(g), CO2(g) and O2(g) and corresponding thermodynamic functions. At high temperatures above 750 °C incongruent vaporization was observed due to a disproportional increase of the vapor pressure of CO2. On this stage also Na2O+, K2O+ and K2CO3+ ions were registered in the mass spectra. Based on the analysis of fragmentation processes of M2CO3 molecules, the sublimation enthalpy ∆subH°298(K2CO3) is obtained to be 360 kJ/mol.

A 2-hydroxyl phenyl imino modified phenanthro[9,10-d]imidazole probe (PPIP) was synthesized and its aggregation-induced emission enhancement (AIEE) phenomenon in aqueous medium was characterized by the Tyndall phenomena, morphologies of scanning electron microphotograph (SEM) as well as the enhanced fluorescence intensities. The AIEE-active PPIP in aggregated states exhibited a sensitive detection for Cu2+ along with the elimination of fluorescence intensity; subsequently, in situ PPIP-Cu2+ complex showed selective fluorescence “turn-on” for Cr3+, providing a potential platform for tandem recognition of Cu2+ and Cr3+. The 1:1 M ratio between PPIP and Cu2+ was confirmed by Job's plot, 1H NMR spectra, mass spectra and density functional theory (DFT) calculations. The detection limits for Cu2+ and Cr3+ were 4.127 × 10−2 μM and 9.404 × 10−1 μM, respectively. Moreover, this successive recognition could be utilized to construct the molecular logic gates by the fluorescence changes. In addition, PPIP was successfully employed for quantitative detecting Cu2+ in real water samples with satisfactory results.