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This study aimed to use different types of ion source gases [synthetic air, nitrogen (N2), and helium (He)] to compare the ionization efficiency of linear, branched, and cyclic hydrocarbon (HC) standards (i.e., hexatriacontane, squalene, and 5-α-cholestane, respectively), condensed aromatics (CA) standards (i.e., coronene, benz[a]anthracene, and n,n′-bis(3-pentyl)perylene-3,4,9,10-bis(dicarboximide)), one n-paraffin standard, containing carbon numbers ranging from C5 to C120, and two saturated HC fractions. In all cases, a positive-ion mode atmospheric pressure chemical ionization coupled to a Fourier transform ion cyclotron resonance mass spectrometer was used. Isooctane reagent was used to facilitate the ionization of n-paraffins. Three ionization mechanisms were observed: electron transfer ([M]rad+), proton transfer ([M+H]+), and hydride abstraction ([M−H]+). For the ionization of HC standards, synthetic air and He gases presented better ionization efficiency and produced mass spectra with greater mass accuracy and signal-to-noise rate. Moreover, linear HCs were preferentially ionized through hydride abstraction (production of [M−H]+ ions), whereas the ionization of unsaturated and cyclic HCs mostly occurred through the production of [M+H]+ and [Mrad+] species. The unique exception is related to 5-α-cholestane, which is ionized as [M−H]+ in the presence of synthetic air. For the CA standards, N2 and synthetic air promoted the detection of CA standards mainly by electron transfer mechanism, [M]rad+ species. Conversely, He favored the proton transfer ionization ([M+H]+) with minimal fragmentation or oxidation of the analyte. In all cases, synthetic air provided mass spectra with excellent signal-to-noise ratio. This performance was attributed to the high reactive-ionizing power of O2 gas over the HC and CA molecules. For the n-paraffin samples, synthetic air and He provided better ionization performance through hydride abstraction ([M−H]+). N2 favored the production and ionization of heteroatomic compound classes (Ox and NOx).

Asphaltenes were obtained from a Brazilian vacuum residue (VR) by precipitation with different ratios of n-heptane/VR to give three asphaltene subfractions. The behavior of these different subfractions in relation to the stability of water-in-oil (W/O) emulsions were evaluated. The whole asphaltene subfraction (AH) was obtained with the addition of n-heptane/VR in a 40:1 ratio (v/v) followed by filtration. Two more asphaltene subfractions (A4 and A10) were obtained by precipitation with n-heptane/VR ratios of 4:1 and 10:1, respectively. The properties of the precipitated asphaltene subfractions were analyzed by atmospheric pressure photoionization (APPI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in positive-ion mode, ultraviolet–visible (UV–Vis) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The FT-ICR MS results showed that the A4 subfraction exhibited a profile with a higher amount of heteroatoms, high polarity and broader molecular weight distribution (Mw). An inverse correlation was observed concerning the degree of aromaticity and solubility in heptane/toluene solutions (onset point). The AH and A10 subfractions were more aromatic than A4, as confirmed by 1H NMR analysis. Also, the asphaltene subfractions promoted greater stability of the emulsions produced. The droplet size distribution and bottle test showed similar results for the stability of the emulsions obtained with the three different subfractions. After the application of centrifugal forces, the formation of a densely packed layer emulsion was observed, containing approximately 85% of water. The stabilization was improved when the W/O interface formed a viscous layer and effectively blocked the water coalescence, which remained stable for two weeks. This is a submitted manuscript of an article published by Elsevier Ltd in Journal of Petroleum Science and Engineering, 14 October 2017.

Two methods of asphaltenes fractionation have been employed to facilitate the characterization of their respective subfractions. The methods are based on step-wise precipitation with different n-hexane/crude oil ratios, and on adsorption onto CaCO3. Three subfractions were produced for each method, being named of 3.5 V, 3.5–6 V, and 6–40 V (for the first method); and non-adsorbed (bulk), adsorbed, and irreversibly adsorbed (for the second method). The fractions were characterized by elementary analysis, nuclear magnetic resonance of proton (1H NMR) and by positive ion-mode electrospray Fourier transform ion cyclotron resonance mass spectrometry (ESI(+)FT-ICR MS). The elemental analysis, described in previous work, revealed that the C/H ratio for whole asphaltene and its sub-fractions varied between a narrow range (0.83–0.88) which means they present similar aromaticity or unsaturation. Furthermore, the elemental analysis corroborates with the 1H NMR analysis suggesting that subfraction 6–40 V presented a more aromatic profile than of remaining subfractions, while for the fractionation using CaCO3, this behavior was observed for the adsorbed subfraction. However, a more detailed molecular information was obtained from ESI(+)-FT-ICR MS data, showing that polar compounds species with lower carbon numbers were mainly found for the irreversibly adsorbed subfraction. Besides, the double bond equivalent (DBE) distribution is an important tool to associate the chemical information with solubility parameters, in which, a narrower DBE distribution was observed for irreversibly adsorbed (for fractionation onto CaCO3) and subfraction 3.5 V (fractionation in n-hexane) samples, indicating that they are less soluble in hydrocarbons. Also, solubility parameters (δ) were calculated from ESI(+)FT-ICR MS data, where the results indicate that subfractions produced in n-hexane have a lower tendency to precipitate in hydrocarbons in relation to subfractions produced onto CaCO3.

Heavy oil fractions studies are of great importance for the oil industry, receiving particular attention in recent decades due to interest in obtaining compounds with higher added value derived from heavy oil fractions. Moreover, these studies also aim to offer solutions to problems caused by these fractions during all oil processing steps. Asphaltenes placed in n-methylpyrrolidone (NMP) produce two fractions with distinct characteristics, soluble and insoluble in NMP (called NS and NI, respectively). In previously studies it was suggested that the NI fraction presents low content of aromatic compounds, opening a new debate on the composition of asphaltene as is widely discussed in the literature. Here, we show the deep characterization of three set of asphaltenes fractions obtained in NMP using Fourier transform ion cyclotron resonance mass spectrometry coupled to positive and negative-ions mode electrospray ionization (ESI(±)-FT-ICR MS), Fourier transform infrared spectroscopy (FTIR), molecular fluorescence and p roton nuclear magnetic resonance ( 1 H NMR) spectroscopy. FTIR, 1 H NMR and molecular fluorescence demonstrated differences among asphaltene fractions studied, in which, NS fractions exhibited a more polar and aromatic character. On the other hand, NI fractions showed nonpolar profile, being proved by the presence of high amounts of alkyl and naphthenic hydrocarbons showing high abundance of alkyl and naphthenic hydrocarbon related compounds. ESI(±)FT-ICR MS data corroborate the FTIR, 1 H NMR and molecular fluorescence data, which show NS fractions with a high proportion of heteroatomic species and higher aromaticity (higher DBE values) compared with NI fractions.

The Cannabis sativa L. plant is rich in a wide variety of cannabinoids. δ9-tetrahydrocannabinol (δ9-THC) is the main chemical compound responsible for its psychoactive effect, and it can be identified as [M+H]+ and [M-H]- ions at m/z 315 and 313, respectively, where M=C21H30O2. However, six other isomeric or isobaric forms of δ9-THC can exist, which makes its unequivocal characterization a challenge. In this work, ultra-high liquid chromatography coupled to traveling wave ion mobility mass spectrometry (UPLC-TWIM-MS) were applied to both electrospray ionization modes (ESI(±)) and used to analyze hashish, marijuana, and parts of the Cannabis Sativa L. plant (flower and leaf). The presence of a complex isomeric mixture of cannabinoids has been identified, and the mixture mainly contains δ9-THC, cannabidiol (CBN-C5 and Mw =310Da), δ9-tetrahydrocannabinolic acid A and B (δ9-THCA-C5 A/B and Mw =358Da) and their isomers. Three isomers of the ions were identified at m/z 315/313, 311, and 357 by using direct infusion ESI-TWIM-MS technique, while higher selectivity was observed in UPLC-ESI-TWIM-MS data, with the maximum isomeric separation between four and five compounds achieved when using single-ion mode (SIM) acquisition. The ions at m/z 311/309, 315/313, 345, and 357 correspond to CBN-C5, δ9-THC, cannabielsioc acid, δ9-THCA-C5 and their isomers, respectively, and they were the main species found. The calculations of collision cross sections were reported for all isomers of cannabinoids and associated with TWIM-MS results.

A method to fractionate and separate nitrogen compounds according to their carbon number is presented here. Typical Brazilian vacuum residue was submitted to solid-phase extraction using a strong cation exchanger to fractionate the basic nitrogen compounds according to their molecular weight. The method described in this paper extended vacuum residue characterization by gradually removing the most basic species that suppress the ionization of compounds with higher mass (and thus less efficiently ionized). Approximately 1393 peaks were assigned when untreated vacuum residue was directly infused into a positive-ion electrospray ionization (ESI(+)) mass spectrometer coupled to Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). In contrast, more than 3500 different nitrogenous elemental compositions were attributed after fractionation. Nitrogen compounds with carbon numbers up to C 100 were detected. Also, new classes (NO, N 2 O, and NOS) of nitrogen compounds were detected after the fractionation.

The purpose of this research is to evaluate, at a molecular level, the removal of nitrogen compounds from vacuum gas oil (VGO), which is used as feedstock for fluid catalytic cracking units. Here, a VGO sample was treated with two different adsorbents: an argillaceous material specifically developed for the removal of nitrogen compounds in middle distillate cuts (kerosene and diesel) and a commercial silica adsorbent. Breakthrough curves were built on two temperature levels (80 and 150 °C), containing different rupture times (from 60 to 420 min), to determine their influence on nitrogen compound removal. All samples, produced from each condition of adsorption, were analyzed by positive and negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [ESI(±)FT-ICR MS]. Besides FT-ICR MS characterization, the total nitrogen content was monitored. FT-ICR MS indicated that the removal of nitrogen compounds by the clay adsorbent was enhanced when the temperature was higher (150 ...

With the advent of a new family of ionization techniques, ambient mass spectrometry (or ambient MS) was introduced as a simple way of generating ions in MS. Among them, the paper spray ionization (PS-MS) technique has demonstrated to be versatile to solve numerous problems in many areas of science. In this work, the PS-MS technique in the positive ionization mode (PS(+)-MS) was applied in two subareas of forensic chemistry: drugs of abuse and documentoscopy. In the first, the PS(+)MS technique was applied to obtain the chemical profiles of illicit drugs such as blotter papers containing 25I-NBOMe, extracts and leaves of natural cannabinoids (Δ9-tetrahydrocannabinol) and synthetic cannabinoids (naphthalen-1-yl-(1-butylindol-3-yl)methanone, (JWH-073); n-(adamantan-1-yl)-1-(4-fluorobutyl)-1H-indazole-3-carboxamide (5F-AKB48); 4-methyl-1-naphthyl-1-pentylindol-3-yl-methanone (JWH-122); 2-(2-methoxyphenyl)-1-(1-pentylindol-3-yl)ethanone (JWH-250); and 4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210)) as well as to determine the authenticity in weight-loss herbal samples. Finally, an analytical method has been developed to quantify eight illicit drugs (3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), meta-chlorophenylpiperazine (m-CPP), methamphetamine (MA), cocaine, lysergic acid diethylamide (LSD), and dimethoxybromoamphetamine (DOB)) where their limit-of-detection ranged from 0.17 to 1 ppb, with linearity R2 > 0.99. The performance of the PS(+)-MS technique was also compared to other ionization sources: leaf spray mass spectrometry (LS-MS), and electrospray ionization mass spectrometry (ESI-MS). In the second part of this study, the PS(+)MS technique was successfully able to obtain the chemical profiles of different commercial blue pens. The relative intensity (RII372) of the methylene blue dye was monitored to discriminate crossings of traces, and to date questioned documents. The chemical profile of the second generation of Brazilian banknotes (R$, reais) was also explored. In general, the PS(+)-MS technique was proved to be an excellent analytical tool in forensic chemistry, acting like a “Swiss army knife”.

Seaweeds are related to anti-inflammatory, anti-bacterial and anti-noceptive effects. This work aimed to verify the potential of seaweed Padina gymnospora (Kützing) Sonder 1871 to improve wound healing in vitro. P. gymnospora was collected at a bethonic area in Espirito Santo. Methanolic extract of P. gymnospora was obtained by percolation. To determine cytotoxicity, colorimetric MTT tests were performed against normal fibroblasts (L929), macrophages (RAW 264.7) and human ovarian carcinoma (OVCAR-3) cell lines using concentration range of 12–110 μg ml−1. To evaluate in vitro wound healing, monolayer of fibroblasts L929 was seeded and artificial wounded. Cell proliferation was blocked by 5 μg ml−1 Mytomycin C. Nitric oxide inhibition was quantified with Raw 264.7 by Griess reaction. Minimal inhibitory concentration (MIC) against Staphylococcus aureus was determined. Eletrospray ionization with Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS) was applied to detail composition of P. gymnospora methanolic extract. No cytotoxic effect in all cell lines was detected until the maximum concentration of 110 μg ml−1. P. gymnospora promoted significantly migration at the concentration of 25 μg ml−1 (p

Asphaltenes are defined as the petroleum fraction insoluble in n-alkanes and soluble in aromatic solvents, such as toluene. Such definition implies that asphaltenes are not a homogeneous material but a mixture of fractions. Asphaltenes represent one of the major contributors to several problematic issues for the petroleum industry. Destabilized asphaltenes can cause arterial clogging within pipelines and wellbores, corrosion and fouling of production equipment, reduction of catalyst activity in refining processes, and other problems. This work describes an investigation of the separation of asphaltenes into three different fractions by adsorption onto silica particles. These fractions (two adsorbed and one non-adsorbed onto silica) were characterized by elemental analysis (C, H, and N), Fourier transform infrared spectroscopy coupled to attenuated total reflectance (ATR–FTIR), proton nuclear magnetic resonance (1H NMR) spectroscopy, and atmospheric pressure photoionization Fourier transform ion cyclotron ...

The application of ambient ionization mass spectrometry such as paper spray ionisation (PSI) is a fast, powerful, and simple method to analyze designer drugs directly on the surface of blotters. PSI-MS does not require nebulizing gas and heating temperature as well as complex protocols for sample preparation. Herein, it was possible to identify and elucidate the chemical structure of designer drugs using tandem mass spectrometry experiments from a triangular blotter. Substances such as lysergic acid diethylamide (LSD), and five new designer drugs (2,5-dimethoxy-4-chloroamphetamine (DOC), 2,5-dimethoxy-4-bromoamphetamine (DOB), 25C-NBOMe, 25B-NBOMe, and 25I-NBOMe) were characterized by PSI-MS. The PSI(+)-MS and PSI(+)-MS/MS data confirmed the assignments of the designer drugs and fragmentation mechanisms have been proposed. From losses of 17 Da (NH3), which is typical of primary amines, the CID results suggest the presence of isomers in the chemical composition of the NBOMe class. Additionally, the data were compared to those of ultra-high-resolution mass spectroscopy (positive-ion electrospray ionization coupled with Fourier transform ion cyclotron mass spectrometry, ESI(+)FT-ICR MS).

RATIONALE There is a need for fast, post-ionization separation during the analysis of complex mixtures. In this study, we evaluate the use of a high-resolution mobility analyzer with high-resolution and ultrahigh-resolution mass spectrometry for unsupervised molecular feature detection. Goals include the study of the reproducibility of trapped ion mobility spectrometry (TIMS) across platforms, applicability range, and potential challenges during routine analysis. METHODS A TIMS analyzer was coupled to time-of-flight mass spectrometry (TOF MS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) instruments for the analysis of singly charged species in the m/z 150-800 range of a complex mixture (Suwannee River Fulvic Acid Standard). Molecular features were detected using an unsupervised algorithm based on chemical formula and IMS profiles. RESULTS TIMS-TOF MS and TIMS-FT-ICR MS analysis provided 4950 and 7760 m/z signals, 1430 and 3050 formulas using the general Cx Hy N0-3 O0-19 S0-1 composition, and 7600 and 22 350 [m/z; chemical formula; K; CCS] features, respectively. CONCLUSIONS TIMS coupled to TOF MS and FT-ICR MS showed similar performance and high reproducibility. For the analysis of complex mixtures, both platforms were able to capture the major trends and characteristics; however, as the chemical complexity at the level of nominal mass increases with m/z (m/z >300-350), only TIMS-FT-ICR MS was able to report the lower abundance compositional trends.

The Cannabis sativa L. plant has a complex chemical composition, containing various chemical compounds such as terpenes, sugars, hydrocarbons, steroids, flavonoids, and amino acids. Few works have attempted to identify the constitutional isomers of cannabinoids that are found in the plant. The present study reported the analysis of seven cannabinoid standards: five neutral and two acidic, as well as Cannabis products (hashish and marijuana) and parts of the Cannabis plant (flower and leaf) using mono-dimensional gas chromatography coupled with mass spectrometry (GC-MS) and two-dimensional gas chromatography coupled with quadrupole MS (GC × GC-QMS), ultra performance liquid chromatography coupled with electrospray ionization-quadrupole-time of flight (UPLC-ESI-QTOF)-MS and UPLC-ESI-travelling wave ion mobility (TWIM)-MS. The results of GC-MS demonstrated close retention times (∆tR = 1.303 min) in separation of the five cannabinoid standards, whereas GC × GC-QMS provided a substantially better identification and distinction of constitutional isomers of cannabinoids, where a total of 11 cannabinoids were identified in the hashish sample. UPLC-QTOF-MS and UPLC-TWIM-MS data obtained complete chemical information, in which ESI(+) revealed the presence of seven constitutional isomers of ∆9-tetrahydrocannabinol (∆9-THC), whereas ESI(-) proved the presence of four isomers of ∆9-tetrahydrocannabinolic acid A (∆9-THCA A).

This work describes a methodology for predicting basic nitrogen and aromatics contents in crude oil, using positive ion mode laser desorption ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and partial least squares (PLS) regression with variable selection based on competitive adaptive reweighted sampling (CARS), in a procedure called CARSPLS regression. The basic nitrogen and aromatics contents were determined using UOP Method 269-10 and ASTM D5443-14, respectively, for 70 samples of Brazilian crude oil. The basic nitrogen values ranged from 0.016% to 0.151% and the aromatics values from 8.4% to 35.1%. The LDI(+)-FT-ICR mass spectra of crude oil samples have profiles that ranged from m / z 200 to 1000, with an average molar mass distribution ( M w ) centered between 554 and 636 Da. Most of the identified organic species are analogues of pyridine and polyaromatic hydrocarbon compounds that belong in the N x , N x [H], HC, and HC[H] classes. Additionally, the number of detected N x species increases systematically with increasing basic nitrogen and aromatics content. The CARS method was used to select the most informative variables for the PLS calibration model, thereby reducing the number of variables from 47,873 to 48 and 10 for basic nitrogen and aromatic compounds, respectively. The prediction model based on CARSPLS presented RMSEP of 0.012 and 3.73 wt% for basic nitrogen and aromatics contents, respectively. In addition, it was possible to verify that the accuracy of CARSPLS is ever better than only using PLS regression (with all variables). The application of CARSPLS algorithm is therefore justified by easier interpretation of the FT-ICR MS data after variables reduction.

The analysis of hydrocarbon using atmospheric or ambient ionization techniques still remains a challenge in mass spectrometry. Traditionally, the ionization occurs via protonation or deprotonation and thus the molecules of interest must have a basic or acidic group to generated [M+H]+ or [M−H]− ions. To overcome such limitation, it is proposed a simple, easy, fast and powerful analytical methodology to ionize saturated (linear and branched), unsaturated, and cyclic hydrocarbons as well as polyaromatic hydrocarbons by atmospheric pressure chemical ionization (APCI) using small hydrocarbons as reagents in a FT-ICR mass spectrometer. These molecules may be present in hydrocarbon fraction samples and paraffin/crude oil blends. Among the APCI hydrocarbon reagents, isooctane provided the best results when compared to pentane, hexane, cyclohexane and heptane. The method renders the ionization of hydrocarbons to yield [M−H]+ ions with no associated fragmentation using nitrogen as sheath gas.

Euphorbia tirucalli aerial parts are popularly used in Brazil for cancer treatment. The elution of the aqueous extract of the plant on silica gel C-18 cartridge furnished a water-soluble fraction, which was analyzed directly into the electrospray ionization (ESI) source combined with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and characterized as a mixture of malic acid glycosides 1 – 5 . The compounds were detected in their deprotonated form [M−H] − , where their exact mass (mass error lower than 1 ppm), molecular formula (C n H h O o ), double bond equivalent (DBE) and connectivity were determined from ESI-(−)-MS and ESI-(−)-MS/MS experiments. The presence of malic acid and glucose, as part of the structures, could originate from crassulacean acid metabolism (CAM) of the plant.

Water-in-oil emulsions constitute a widespread issue for the oilfield industry. Indeed, the phases of water-in-oil emulsions must be separated as soon as possible in the production chain. These emulsions can be fairly stable due to certain intrinsic components in crude oil; therefore, adding chemicals – demulsifiers – to aid this separation is very common. Selecting the ideal demulsifier can save time and money, and in this context two-dimensional (2D) low-field nuclear magnetic resonance (NMR) is a promising technique because it allows for the separate study of the oil and water phases without the need for physical separation. In this study, four laboratory-made emulsions were used to investigate the demulsification process via low-field 1H NMR, allowing for the investigation of the correlation between the diffusion coefficient (D) and transverse relaxation time (T2) in 2D D–T2 plots. The three commercial demulsifiers used in this process (A, B and C) were characterised by positive-ion electrospray ionisation (ESI(+)) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The ESI(+)–FT-ICR mass spectra recorded for the commercial demulsifiers showed distinct chemical profiles, with two samples (A and B) being composed of surfactants containing isoprene and glycol propylene oligomer species, where the ions detected in the m/z 200–700 region were separated by m/z 42 and 58 units, respectively. A more abundant and complex chemical profile was observed for sample C, in which pyridine and sulphoxide analogue species were identified. The 2D D–T2 plots clearly showed that the separation of water and oil phases can be monitored and allowed for the classification of the demulsifiers according to their performance in the physical separation of the phases: demulsifier A > demulsifier B > demulsifier C.

Competitive adaptive reweighted sampling-partial least squares (CARS-PLS) and negative-ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(-) FT-ICR MS) data were adopted to assess the total acid number (TAN) of crude oil distillation cuts. Two crude oil samples and 24 derivatives with TAN ranging from 0.20 to 0.39 mg of KOH g-1 were investigated. The multivariate calibration PLS model was built with 18 calibration samples and tested with 8 validation samples. CARS-PLS reduced the number of variables from 1610 to only 4, allowing the identification of molecular formulas that are truly related to the TAN. The root mean square error of prediction (RMSEP) obtained was 0.01 mg of KOH g-1, which is lower than the error when using all variables (0.03 mg of KOH g-1). Finally, it was observed that the N and O2 compound classes are the most important classes for providing a better correlation between ESI(-) FT-ICR mass spectra and TAN values.

Atmospheric solids analysis probe mass spectrometry (ASAP-MS) is a powerful tool for analysis of solid and liquid samples. It is an excellent alternative for crude oil analysis without any sample preparation step. Here, ASAP-MS in positive ion mode, ASAP(+)-MS, has been optimized for analysis of condensed aromatics (CA) standards, crude oil, and paraffinic fraction samples using a Synapt G2-S HDMS. Initially, two methodologies were used to access the chemical composition of samples: (1) using a temperature gradient varying from 150 to 600 °C at a heating rate of 150 °C min-1, and (2) with constant temperature of 300 and 400 °C. ASAP(+)-MS ionized many compounds with a typical petroleum profile, showing a greater signals range of m/z 250-1300 and 200-1400 for crude oil and paraffin samples, respectively. Such performance, mainly related to the detection of high molecular weight compounds (>1000 Da), is superior to that of other traditional ionization sources, such as ESI, APCI, DART, and DESI. Additionally, the CA standards were identified in both forms: radicals, [M]+•, and protonated cations, [M + H]+, with minimum fragmentation. Therefore, ASAP was more efficient in accessing the chemical composition of nonpolar and polar compounds. It is promising in its application with ultrahigh resolution MS instruments, such as FT-ICR MS and Orbitrap, since molecular formulas with greater resolution and mass accuracy (

Asphaltenes analysis still remains a challenge due to their unknown molecular structure and self-associative behavior. FT-ICR MS analyses using five different ionization methods, ESI, APCI, APPI, LDI and MALDI, in both positive and negative mode were performed. A characteristic and typical behavior was observed for the experiments using LDI(±) and MALDI(±)FT-ICR analyses: a broadband mass spectrum ranging from m/z 500 to 3000 was observed with a 24 Da interval. This phenomenon was attributed to fullerene cluster formation. The most abundant allotropic form of fullerene, C 60 , was observed at m/ z 719.99914. These species were not observed in APCI(+)/APPI(+) analyses. This last analysis of asphaltene samples doped with the C 60 solution promptly reveals the typical fullerene ions. LDI(+) analyses of pure C 60 showed condensation products. These results indicate a clusterization of asphaltenes in the LDI/MALDI plume, which showed a highly dependency on the laser power density. The dispersion of LDI results on carbonaceus samples in the literature is associated with the lack of control of these parameters. However, to access the sample composition, APPI and APCI should be more suitable.

Negative-ion mode electrospray ionization, ESI(-), with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was coupled to a Partial Least Squares (PLS) regression and variable selection methods to estimate the total acid number (TAN) of Brazilian crude oil samples. Generally, ESI(-)-FT-ICR mass spectra present a power of resolution of ca. 500,000 and a mass accuracy less than 1 ppm, producing a data matrix containing over 5700 variables per sample. These variables correspond to heteroatom-containing species detected as deprotonated molecules, [M - H](-) ions, which are identified primarily as naphthenic acids, phenols and carbazole analog species. The TAN values for all samples ranged from 0.06 to 3.61 mg of KOH g(-1). To facilitate the spectral interpretation, three methods of variable selection were studied: variable importance in the projection (VIP), interval partial least squares (iPLS) and elimination of uninformative variables (UVE). The UVE method seems to be more appropriate for selecting important variables, reducing the dimension of the variables to 183 and producing a root mean square error of prediction of 0.32 mg of KOH g(-1). By reducing the size of the data, it was possible to relate the selected variables with their corresponding molecular formulas, thus identifying the main chemical species responsible for the TAN values.

The synthetic cannabinoids (SCs) represent the most recent advent of the new psychotropic substances (NPS) and has become popularly known to mitigate the effects of the Δ(9)-THC. The SCs are dissolved in organic solvents and sprayed in a dry herbal blend. However, little information is reported on active ingredients of SCs as well as the excipients or diluents added to the herbal blend. In this work, the direct infusion electrospray ionization Fourier transform ion cyclotron mass spectrometry technique (ESI-FT-ICR MS) was applied to explore the chemical composition of nine samples of herbal extract blends, where a total of 11 SCs (UR-144, JWH-073, XLR-11, JWH-250, JWH-122, AM-2201, AKB48, JWH-210, JWH-081, MAM-2201 and 5F-AKB48) were identified in the positive ionization mode, ESI(+), and other 44 chemical species (saturated and unsaturated fatty acids, sugars, flavonoids, etc.) were detected in the negative ionization mode, ESI(-). Additionally, CID experiments were performed, and fragmentation pathways were proposed to identify the connectivity of SCs. Thus, the direct infusion ESI-FT-ICR MS technique is a powerful tool in forensic chemistry that enables the rapid and unequivocal way for the determination of molecular formula, the degree of unsaturation (DBE-double bond equivalent) and exact mass (

International audience; The analysis of crude oil and its fractions by applying ambient ionization techniques remains underexplored in mass spectrometry (MS). Direct analysis in real time (DART) in the positive-ion mode was coupled to a linear quadrupole ion trap Orbitrap mass spectrometer (LTQ Orbitrap) to analyze crude oil, paraffin samples, and porphyrin standard compounds. The ionization parameters of DART-MS were optimized for crude oil analysis. DART-MS rendered the optimum conditions of the operation using paper as the substrate, T = 400°C, helium as the carrier gas, and a sample concentration 6 mg mL-1. In the crude oils analysis, the DART(+)-Orbitrap mass spectra detected the typical N, NO, and O-containing compounds. In the paraffin samples, oxidized hydrocarbon species (Ox classes, where x = 1-4) with double-bond equivalent of 1-4 were detected, and their structures and connectivity were confirmed by collision-induced dissociation (CID) experiments. DART(+)-MS has identified the porphyrin standard compounds as [M + H]+ ions of m/z 615.2502 and 680.1763, where M = C44H30N4 and C44H28N4OV, respectively, based on the formula assignment and by phenyl losses observed on CID experiments. © 2015 American Society for Mass Spectrometry.

Objective: To evaluate the influence of fertilization and phenological stages on secondary metabolites production and chemoprotective effects of Coriandrum sativum (C. sativum) L. Methods: The plants were grown under organic or chemical fertilizer, collected at vegetative and flowering development stages and their hydroalcoholic extracts were analyzed by phytochemicals methods, mass spectrometry, antioxidant and antimutagenic assays. Results: All extracts exhibited metabolites such as coumarins, flavonoids and steroids, and mass spectrometry showed similar molecular peaks among the extracts evaluated, suggesting the presence of palmitic and α -linolenic acids. Vegetative C. sativum extract grown under chemical fertilizer showed better antioxidant activity, according to the DPPH assay. Vegetative C. sativum extracts grown under organic and chemical fertilizer were able to effectively reduce micronucleous frequency in the simultaneous and pre-treatment protocols, especially reaching 55.90% of damage reduction in the pre-treatment protocol. Conclusions: These findings suggest that chemical fertilization promotes an increase in the content of flavonoids in C. sativum and, consequently, leads to better antioxidant and antimutagenic activities, as well as reinforces the potential uses of this culinary plant in health promotion and disease prevention.

Drug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5-dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotometry (UV-Vis), attenuated total reflection with Fourier transform infrared spectroscopy(ATR-FTIR), gas chromatography mass spectrometry (GC-MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). First, the TLC technique was effective for identifying spots related to 25C-, 25B- and 25I-NBOMe compounds, all with the same retention factor, Rf ≈ 0.50. No spot was detected for 2,5-dimethoxy-4-bromoamphetamine, 2,5-Dimethoxy-4-chloroamphetamine or lysergic acid diethylamide compounds. ATR-FTIR preserved the physical-chemical properties of the material, whereas GC-MS and ESI-MS showed better analytical selectivity. ESI(+)FT-ICR MS was used to identify the exact mass (m/z428.1706 for the [M + H]+ ion), molecular formula (M = C18H22INO3), degree of unsaturation (DBE = 8) and the chemical structure (from collision induced dissociation, CID, experiments) of the 25I-NBOMe compound. Furthermore, the ATR-FTIR and CID results suggested the presence of isomers, where a second structure is proposed as an isomer of the 25I-NBOMe molecule.