Direct Detection of Triacetone Triperoxide (TATP) in Real Banknotes from ATM Explosion by EASI‐MS

In Brazil, automated teller machine (ATM) has become a major target of theft incursions toward explosion. Efficient analysis of explosives residues on suspect banknotes is a serious issue in forensic labs, and guide to the crime solution. Easy ambient sonic‐spray ionization mass spectrometry (EASI‐MS) is shown to be a simple and selective screening tool to identify peroxide explosives on real banknotes collected from ATM explosion. Analyses were carried out directly on the banknotes surfaces without any sample preparation, identifying triacetone triperoxide (TATP) and diacetone diperoxide (DADP). Homemade EASI source was coupled to ultrahigh‐resolution and ultrahigh accuracy FT‐ICR MS and revealed the ion of m /z 245 correspondent to sodiated TATP [C₉H₁₈O₆Na]⁺ and the ion of m /z 171 related to sodiated DADP [C₆H₁₂O₄Na]⁺, ions that is the sodiated DADP and the ions of m /z 173 and 189 related to [C₆H₁₄O₄Na]⁺ and [C₆H₁₄O₄K]⁺, respectively, which are associated to chemical markers of TATP domestic route synthesis. EASI source coupled to a single quadrupole mass spectrometer provides an intelligent and simple way to identify the explosives TATP, DADP and its domestic synthesis markers.     

Characterization of castor bean neutral lipids by mass spectrometry/mass spectrometry

A method has been developed for the characterization of intact neutral lipids isolated from castor bean (Ricinus communis L.) by mass spectrometry/mass spectrometry (MS/MS). The molecular weights of the trimethylsilyl (TMS) derivatives of the neutral lipids are determined by using both electron impact and chemical ionization (ammonia). Collision-induced dissociation daughter spectra of the (M-CH₃)⁺ ions yield fragment ions that allow easy determination of the acyloxy groups present. The chainlength and degree of unsaturation for each acyloxy group are indicated by R in the ion represented by the general formula (RCO + 74)⁺. Other ions of diagnostic value include (M-RCOO)⁺, (M-RCOOH)⁺, [(M-CH₃-RCOOH]⁺ and [(M-RCOOH)-16]⁺. The presence of a TMS group in any of these fragments results in the formation of ions representing the loss of OTMSH. Prior to MS/MS analysis, partial fractionation by high-performance liquid chromatography (according to degree of unsaturation in the neutral lipids) is useful because daughter spectra are generated free of any isotopic contamination, and minor components are concentrated in single fractions, which aids their characterization. By using this method, 11 neutral lipids were characterized in castor bean.     

Sensitivity of positive ion mode electrospray ionization mass spectrometry (ESI MS) in the analysis of purine bases in ESI MS and on-line electrochemistry ESI MS (EC/ESI MS)

A cone-shaped MS inlet and on-line electrochemistry (EC) were used to enhance the ionization efficiency in electrospray ionization mass spectrometry (ESI MS) of purine bases. A pathway of positive ion mode ESI may involve oxidation of purine bases, guanine, adenine, xanthine and hypoxanthine, by 1e⁻, 1H⁺ processes. The electrospray process generates dimers of purine bases that are detected in ESI MS as protonated ions, except for xanthine, for which a protonated radical dimer is detected. Thus electrochemical oxidation of purine bases during ESI may generate reactive radicals that can subsequently dimerize. Dimer formation is facilitated in ESI MS when the carrier solution pH is high. The positive ion mode ESI MS ionization is consistent with the reactivity of the bases toward oxidation. Furthermore, the formation of the protonated ions, and Na⁺ and K⁺ adducts of the bases, expected in positive ion ESI MS, are observed. In addition, unusual H-bonding of purine bases guanine and xanthine is confirmed by ESI MS. Application of low EC voltage to the on-line EC cell in EC/ESI MS improves the sensitivity and correlates with the decrease of the intensity of the dimers, possibly as a result of their further oxidation.     

Investigations of SP-AMS Carbon Ion Distributions as a Function of Refractory Black Carbon Particle Type

The soot particle aerosol mass spectrometer (SP-AMS) instrument combines continuous wave laser vaporization with electron ionization aerosol mass spectrometry to characterize airborne, refractory black carbon (rBC) particles. The laser selectively vaporizes absorbing rBC-containing particles, allowing the SP-AMS to provide direct chemical information on the refractory and non-refractory chemical components, providing the potential to fingerprint various rBC particle types. In this study, SP-AMS mass spectra were measured for 12 types of rBC particles produced by industrial and combustion processes to explore differences in the carbon cluster (C_n⁺) mass spectra. The C_n⁺ mass spectra were classified into three categories based on their ion distributions, which varied with rBC particle type. The carbon ion distributions were investigated as a function of laser power, electron ionization (on/off), and ion charge (positive or negative). Results indicate that the dominant positive ion-formation mechanism is likely the vaporization of small, neutral carbon clusters followed by electron ionization (C₁⁺ to C₅⁺). Significant ion signal from larger carbon cluster ions (and their fragment ions in the small carbon cluster range), including mid carbon (C₆⁺ to C₂₉⁺) and fullerene (greater than C₃₀⁺) ions, were observed in soot produced under incomplete combustion conditions, including biomass burning, as well as in fullerene-enriched materials. Fullerene ions were also observed at high laser power with electron ionization turned off, formed via an additional ionization mechanism. We expect this SP-AMS technique to find application in the identification of the source and atmospheric history of airborne ambient rBC particles.

Copyright 2015 American Association for Aerosol Research     

Kinetics of Ion Formation in the Volumetric Reaction of Methane with Air

The formation of ions in the volumetric reaction of methane and hydrogen with air is analyzed. In methane–air mixtures, the highest concentrations are observed for NO⁺, NO₃ ^–, CO₃ ^–, CO₄ ^–, OH^–, and NO₂ ^– ions. In hydrogen–air mixtures, maximum concentrations are characteristic for NO⁺, OH^–, H₃O⁺, O^–, and O₂ ^– ions. In both rich and lean mixtures after ignition there is a long time interval during which the ion concentrations are far from equilibrium. The duration of this interval and the ion concentrations in it depend on the initial parameters of the mixture and the air–fuel ratio. Key words: volumetric reaction of methane with air, ion-molecular reactions, kinetics, ions.     

Fast atom bombardment and tandem mass spectrometry of phosphatidylserine and phosphatidylcholine

Fast atom bombardment (FAB) desorption of phosphatidylserine and various phosphatidylcholines produces a limited number of very informative negative ions. Especially significant is the formation of (M-H)⁻ ions for phosphatidylserine, a compound which does not yield informative high mass ions by other ionization methods. Phosphatidylcholines of not yield (M-H)⁻ ions but instead produce three characteristic high mass ions, (M-CH ₃ ⁺ _⁻, [M-HN(CH₃) ₃ ⁺ ]⁻ and [M-HN(CH_{3 3} ⁺ -C₂H₂]⁻. Both classes of lipids also yield anions attributed to the carboxylate components of these complex lipids. FAB desorption in combination with collisional activation allows for characterization of fragmentation and determination of structural features. Collisional activation of the carboxylate anion fragments from the complex lipids is especially informative. Structural characterization of the fatty acid chain can be achieved as the released saturated carboxylate anions undergo a highly specific 1,4-elimination of H₂, which results in the losses of the elements of CH₄, C₂H₆, C₃H₈...in a fashion entirely consistent with the chemistry of carboxylate anions desorbed from free fatty acids. These C_nH_2n+2 losses begin at the alkyl terminus and progress along the entire alkyl chain. Modified fatty acids undergo a similar fragmentation; however, the modification affects the series of C_nH_2n+2 losses in a manner which permits determining the type of modification and its location on the fatty acid chain.     

Capillary supercritical fluid chromatography-atmospheric pressure chemical ionization mass spectrometry of triacylglycerols in berry oils

A capillary supercritical fluid chromatograph (SFC), combined with a triple-quadrupole mass spectrometer (MS) via a liquid chromatography-atmospheric pressure chemical ionization (LC-APCI) interface, was utilized in the analysis of berry oil triacylglycerols. No modification of the commercially available interface was required. Vapor of different solvents, such as methanol, isopropanol, water, or ammonium hydroxide in methanol, was introduced in the sheath gas flow in the APCI source to achieve adequate ionization of triacylglycerols. The separation of triacylglycerols according to acyl carbon number and degree of unsaturation was accomplished on a 20 m × 50 μm i.d. SB-Cyanopropyl-25 column. The resolution of triacylglycerols in the reconstructed ion chromatogram and the sensitivity of the SFC-(APCI)MS system was comparable to or slightly better than that obtained with a flame ionization detector. No baseline drifting was observed during the SFC density programming. Triacylglycerols formed diagnostic [M + H]⁺ and [M - RCOO]⁺ ions with all tested reactant ion solvents except with ammonium hydroxide in methanol, which formed abundant [M + 18]⁺ ions instead of [M + H]⁺ ions. The abundance of the [M + H]⁺ ion increased with increasing degree of unsaturation of a triacylglycerol, whereas the abundance of the [M - RCOO]⁺ ion depended on the regiospecific distribution of the fatty acid moiety between the sn-1/3 positions and the sn-2 position and on the number of double bonds.     

Electrospray mass spectrometry for characterizing polyglycerols and the effects of adduct ion and cone voltage

Polyglycerol intermediates have been characterized by liquid chromatography-mass spectrometry (LC-MS) with electrospray ionization (ESI). Linear and cyclic components from n=2–23 in a sample of decaglycerol, for example, have been resolved in the second dimension or mass axis. Molecular weight (MW) distributions for tri-, hexa-, and decaglycerol products have been analyzed as a function of cone voltage and adduct ion (H⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, and NH₄ ⁺). A different combination is required to obtain a reliable MW distribution for each polyglycerol intermediate. The best distribution obtained by ESI/MS is determined by comparing the calculated hydroxyl number and cyclic content to that obtained by wet chemistry and gas chromatography, respectively. Once ESI/MS conditions are established, the distribution can be used, for the first time in polyglycerol analysis, to calculate important parameters such as number average MW, weight average MW, polydispersity, % cyclics, hydroxyl number, wt% above n=6, etc.     

Thermal Analysis of Magnesium/Perfluoropolyether Pyrolants

Exothermic reactions between metals and fluorinated polymers are found in a variety of energetic materials, including reactive binder systems and the Magnesium‐Teflon‐Viton incendiary composition. This paper describes the reactions between a high molecular weight perfluoropolyether, Fomblin Y 140/13, and magnesium in a variety of morphologies including μm‐scale powders and nano‐scale layered films. Using Temperature Programmed Desorption and Temperature Programmed Reaction we have found that the magnesium‐perfluoropolyether interaction is characterized by: (1) competition between Fomblin decomposition and desorption, and (2) magnesium passivation by the formation of magnesium fluoride. Differential Scanning Calorimetry measurements establish a lower‐bound estimate of the specific reaction energy of 9.2 kJ g⁻¹. High molecular weight Fomblin (6500 amu) undergoes a competitive reaction/desorption process with desorption occurring at 550 K and decomposition at 610 K. Decomposition becomes more favorable relative to desorption for higher heating rates and thicker films. Perfluoropolyethers produce several characteristic ions in the 70 eV election ionization mass spectra, with the CF₃⁺ ion being the most abundant ion observed during both the molecular desorption and decomposition. Larger fragment ions with masses of 235 and 285 amu are observed in relatively high concentrations during desorption and low concentrations during decomposition. The reaction between magnesium and Fomblin begins at 400 K, producing CF₃⁺, CO⁺, and C₂F₅⁺ in the electron ionization mass spectrum. We propose that these reactions form a passivating layer of magnesium fluoride that protects the remaining metal as it approaches the magnesium melting point. Most of the reaction takes place at 800 K and above when the magnesium fluoride film ruptures.     

Identification and analysis of wax esters by mass spectrometry

Several ions in the mass spectra of wax esters were related to the molecular structures. Assigned structures of ions were confirmed by deuterium labeling. A simple, direct method for quantititive analyses of mixtures was developed. The method involved a comparison of sets of three ions, RCO₂H⁺, RCO₂H₂ ⁺ and [R′−1]⁺ from all compounds in the mixture. The method was found applicable for mixtures of unsaturated wax esters after reduction with tetradeuterio hydrazine. Presented in part before the ISF-AOCS World Congress, Chicago, September 1970. Part III of a series of mass spectrometry of lipids. For VI see Lipids.     

Über die Natur der Übergangsmetall-Kohlenstoff-σ-Bindung. II. Massenspektrometrische Untersuchungen von Mono-organyl-Übergangsmetallkomplexen des Phthalocyanins und Salens

The Nature of the Transition Metal to Carbon σ-bond. II. Mass Spectrometric Investigations of Mono-organyl-Transition Metall Complexes of Phthalocyanine and Salen In the mass spectra of monomethyl and monophenyl complexes of Fe(III) and Co(III) phthalocyanines (RMPc) there are observed peaks at higher mass numbers than that of the molecular ion which are described to products containing more than one organyl group. It is concluded from the mass spectra and the ionization efficiency curves of the ions R₂MPc⁺, RMPc⁺ and MPc⁺ that, due to the high temperature in the inlet system of the mass spectrometer, in the solid state a loss of the organyl residue R and an attack of the radicals at the phthalocyanine ring takes place. The mass spectra of methyl- and phenyl-cobalt(III)-salen do not contain any peaks at higher mass numbers than the molecular ion. The problems of mass spectrometric determination of the strength of the transition metal to carbon σ-bond are discussed.     

Application of selective ion monitoring to the analysis of molecular species of vegetable oil triacylglycerols separated by open-tubular column GLC on a methylphenylsilicone phase at high temperature

Analyses of the molecular species of authentic triacylglycerols and of soybean triacylglycerols, which were separated on a fused silica open-tubular column coated with a methylphenylsilicone gum stationary phase, were carried out by selective ion monitoring mass spectrometry. It was determined that peak assignments could be made by selecting certain characteristic ions with the same retention time on the SIM profile, that is, three ions of the type RCO⁺ corresponding to the fatty acyl residues (R₁CO⁺, R₂CO⁺ and R₃CO⁺) and the corresponding three M-acyl ions ([M-OCOR₁]⁺, [M-OCOR₂]⁺ and [M-OCOR₃]⁺ instead of the molecular ion. The yield of [RCO-1]⁺ and [RCO-2]⁺ and relating these to the unsaturated fatty acyl residues is inconvenient for an exact peak assignment. The SIM method was further applied to the peak assignment of the triacylglycerols from palm, cottonseed and safflower oils and certain new fatty acid combinations are proposed.     

Highly Efficient and Selective Transport of Cu(II) with a Cooperative Carrier Composed of Tetraaza-14-Crown-4 and Oleic Acid through a Bulk Liquid Membrane

Tetraaza-14-crown-4 and oleic acid was successfully applied for transport of Cu(II) in chloroform bulk liquid membrane. The uphill moving of Cu(II) during the liquid membrane transport process has occurred. The main effective variable such as the type of the metal ion acceptor in the receiving phase and its concentration, tetraaza-14-crown-4 and oleic acid concentration in the organic phase on the efficiency of the ion-transport system were examined. By using L-cysteine as a metal ion acceptor in the receiving phase, the maximum amount of copper (II) transported across the liquid membrane was achieved to 96 ± 1.5% after 140 minutes. The selectivity of copper ion transport from the aqueous solutions containing Pb²⁺, Tl⁺, Ag⁺, Co²⁺, Ni²⁺, Mg²⁺, Zn²⁺, Hg²⁺, Cd²⁺ and Ca²⁺ ions were investigated. In the presence of CH₃COONH₄ and Na₄P₂O₇ as suitable masking agents in the source phase, the interfering effects of Pb⁺² and Cd²⁺ were diminished drastically.     

Ionization Efficiency Curves by the Retarding Potential Difference (RPD) Method

Ionization efficiency curves obtained by the RPD (retarding potential difference) method are presented for Cycl. C₄F₈^?, H_g⁺, C₂ H₂⁺ and C₂ F₄⁺. The C₄ F₈^? resonance capture curve is given for a variety of experimental conditions. The curves for the positive ions are compared with similar curves obtained previously by the technique of photoionization combined with mass analysis. The results are discussed in terms of possible relaxation effects and other artefacts in the RPD method and in terms of threshold laws of ionization by electron and photon impact. Special emphasis is placed on autoionization processes. Experimental conditions, under which the RPD ion source may be reliably used, are specified.     

Identification of steroids by chemical ionization mass spectrometry

Chemical ionization (CI) mass spectra of various natural and synthetic steroids have been studied using methane, isobutane, ammonia, trideuterioammonia and hydroxy anion as reagent gases. The CI spectra of steroids give simple and well characterized ions, which provide information about molecular weight as well as functionalities in the molecules. Trideuterioammonia exchanges rapidly with active hydrogens (e.g., OH, SH, COOH, NH₂) in steroid molecules in the CI reaction and thus provides a convenient means of active hydrogen determination by mass spectrometry. Application of various CI processes to the analysis of steroids and conjugates have been made. Low levels of hydroxycholesterols in biological samples and in cholesterol autoxidation products were identified by the 4 ion patterns, [M+NH₄]⁺, [M−OH+NH₃]⁺, [M−OH]⁺ and [M−H₂ O−OH]⁺, in ammonia CI. The position of hydroxy functions in the cholesterol side chain can be identified from the methane CI of hydroxycholesterol trimethylsilyl (TMS) derivatives. Sterol carboxylic esters can be identified as the ammonium adduct ion of the intact molecule, [M+NH₄]⁺, in ammonia CI. Isobutane and hydroxy anion CI spectra of the steroid esters give abundant ion fragments of both steroids and carboxylic acid moieties. Identification of free bile acids and steroid glycosides without derivatization is also feasible with the CI process when ammonia is used as reagent gas.     

Compositional analysis of natural wax ester mixtures by tandem mass spectrometry

Tandam mass spectrometry is particularly suited for the analysis of complex, natural wax ester mixtures R₁-CO₂-R₂. Reduction of the mixture with deuterium provides species that are separble (through mass spectrometry) based on the number of original double bonds. Chemical ionization with isobutane produces high yields of protonated molecular ions and very little further fragmentation. These ions are separated by the first mass filter and then dissociated through collisions with argon. The positively charged dissociation products are almost exclusively the protonated acid ions (R₁-CO₂ H₂)⁺ that can then be separated by the second mass filter before detection and quantitation. The technique overcomes many of the obstacles previously faced during wax ester analysis. Results from this method are compared with those obtained by previous work, and the isomer composition of a new wax ester oil, orange roughy oil, is given. *** DIRECT SUPPORT *** A03O2445 00003     

Physical and electrochemical properties of low molecular weight poly(ethylene glycol)‐bridged polysilsesquioxane organic–inorganic composite electrolytes via sol–gel process

A new class of ionic conducting organic/inorganic hybrid composite electrolyte with high conductivity, better electrochemical stability and mechanical behavior was prepared through the sol–gel processing between ethylene‐bridged polysilsesquioxane and poly(ethylene glycol) (PEG). The composite electrolyte with 0.05 LiClO₄ per PEG repeat unit has the best conductivity up to 10^?4 S/cm at room temperature with the transference number up to 0.48 and an electrochemical stability window as high as 5.5 V versus Li/Li⁺. Moreover, the effect of the PEG chain length on the properties of the composite electrolyte has also been studied. The interactions between ions and polymer have also been investigated for the composite electrolyte in the presence of LiClO₄ by means of FTIR, DSC, and TGA. The results indicated the interaction of Li⁺ ions with the ether oxygen of the PEG, and the formation of transient crosslinking with LiClO₄, resulting in an increase of the T_g of the composite electrolyte. The VTF‐type behavior of the ionic conductivity implied that the diffusion of the charge carriers was assisted by the segmental motions of the polymer chains. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2752–2758, 2007     

Atmospheric-pressure ionization mass-spectrometric analysis of new anionic surfactants: The alkylpolyglucoside esters

Atmospheric-pressure ionization mass spectrometry has been successfully applied to characterization of a new class of anionic surfactants, the alkylpolyglucoside esters of sulfosuccinic, citric and tartaric acid. Complex mixtures of final and intermediate products were injected directly into the ion source without prior chromatographic separation. The constituents were identified on the basis of quasi-molecular ions: cationized ions or solute-solute cluster ions in positive-ion mode, and deprotonated ions in negative-ion mode. The mass-spectrometric data show that all three final products contain one nonionic and two different types of anionic surfactants. The “real time,” highly sensitive mass-spectrometric approach proposed here is well suited for quality control testing of tensides, to ensure the safety of the final product, and for the validation of the manufacturing process, because it is able to identify the individual components of the mixture.     

Pervaporation separation of dimethyl carbonate/methanol mixtures with regenerated perfluoro‐ion‐exchange membranes in chlor‐alkali industry

The waste perfluoro‐ion‐exchange membranes (PFIEMs) in chlor‐alkali industry were regenerated and used to the separation of dimethyl carbonate (DMC)/methanol (MeOH) mixtures by pervaporation process. The energy‐dispersive spectrum (EDS) demonstrates that the impurities on the surfaces of waste PFIEMs can be effectively cleared by the regeneration process. The degree of swelling, sorption, and pervaporation properties of the regenerated PFIEMs with different counter ions were investigated. The results indicate that the counter ions of PFIEMs conspicuously influence the degree of swelling, sorption, and pervaporation properties for DMC/MeOH mixtures. The degree of swelling and solubility selectivity both decreases with the alkali metal counter ions in the sequence: Li⁺ > Na⁺ > K⁺ > Cs⁺. The degree of swelling increases with MeOH concentration increasing in feed liquid. The pervaporation measurements illustrate that the permeation flux decreases and the separation factor increases with the rising in ion radius of counter ions. The increase of feed concentration (MeOH) and feed temperature is advantageous to improve permeation flux while at the cost of separation factor decreasing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A Thermal Desorption Chemical Ionization Ion Trap Mass Spectrometer for the Chemical Characterization of Ultrafine Aerosol Particles

The development of a thermal desorption chemical ionization ion trap mass spectrometer for the chemical characterization of ultrafine aerosol particles is reported and first experimental results are presented. Atmospheric particles are size-classified and collected using a unipolar charger, a radial differential mobility analyzer and an electrostatic precipitator, and analyzed after thermal desorption and chemical ionization using an ion trap mass spectrometer. Integration of an ion trap mass spectrometer allows for fast scans of the entire mass spectrum every 0.5 s and bears the potential to identify unknown particulate compounds by tandem mass spectrometry. Particle collection efficiencies range from 90–100% for 25 nm particles to about 50% for 40 nm particles. In the current configuration, the absolute sensitivity of the instrument with regard to ammonium is in the range of 10–100 pg NH ⁺ ₄ . In ambient samples collected in the Colorado Front Range, NH ⁺ ₄ was the major signal peak in the positive ion spectrum, and additional minor signals and peak patterns of organic compounds including methylamine were found.