Desorption Chemical Ionization Mass Spectrometry Research Articles

Implications for new particle formation in air of the use of monoethanolamine in carbon capture and storage.

Alkanolamines are currently being deployed in carbon capture and storage (CCS) technology worldwide, and atmospheric emissions have been found to coincide with locations exhibiting elevated concentrations of methanesulfonic acid (MSA). It is thus critical to understand the fate and potential atmospheric reactions of these chemicals. This study reports the characterization of sub-10 nm nanoparticles produced through the acid-base reaction between gas phase monoethanolamine (MEA) and MSA, a product of organosulfur compound oxidation in air, using a flow reactor under dry and humid (up to ∼60% RH) conditions. Number size distribution measurements show that MEA is even more efficient than methylamine in forming nanoparticles on reaction with MSA. This is attributed to the fact that the MEA structure contains both an -NH2 and an -OH group that facilitate hydrogen bonding within the clusters, in addition to the electrostatic interactions. Due to this already strong H-bond network, water has a relatively small influence on new particle formation (NPF) and growth in this system, in contrast to MSA reactions with alkylamines. Acid/base molar ratios of unity for 4-12 nm particles were measured using thermal desorption chemical ionization mass spectrometry. The data indicate that reaction of MEA with MSA may dominate NPF under some atmospheric conditions. Thus, the unique characteristics of alkanolamines in NPF must be taken into account for accurate predictions of impacts of CCS on visibility, health and climate.

The AERosol and TRACe gas Collector (AERTRACC): an online-measurement-controlled sampler for source-resolved emission analysis

Abstract. Probing sources of atmospheric pollution in complex environments often leads to the measurement and sampling of a mixture of different aerosol types due to fluctuations of the emissions or the atmospheric transport situation. Here, we present the AERosol and TRACe gas Collector (AERTRACC), a system for sampling various aerosol types independently on separate sampling media, controlled by parallel online measurements of particle, trace gas, and meteorological variables, like particle number or mass concentration, particle composition, trace gas concentration, and wind direction and speed. AERTRACC is incorporated into our mobile laboratory (MoLa) which houses online instruments that measure various physical and chemical aerosol properties, as well as trace gas concentrations. Based on preparatory online measurements with the whole MoLa setup, suitable parameters measured by these instruments are used to define individual sampling conditions for each targeted aerosol type using a dedicated software interface. Through evaluation of continuously online-measured data with regard to the sampling conditions, the sampler automatically switches between sampling and non-sampling for each of up to four samples, which can be collected in parallel. The particle phase and gas phase of each aerosol type, e.g., source emissions and background, are sampled onto separate filters with PM1 and PM10 cutoffs and thermal desorption tubes, respectively. Information on chemical compounds in the sampled aerosol is obtained by means of thermal desorption chemical ionization mass spectrometry (TD-CIMS) as the analysis method. The design, operation, and characterization of the sampler are presented. For in-field validation, wood-fired pizza oven emissions were sampled as targeted emissions separately from ambient background. Results show that the combination of well-chosen sampling conditions allows more efficient and effective separation of source-related aerosols from the background, as seen by the increases of particle number and mass concentration and concentration of organic aerosol types, with minimized loss of sampling time compared to alternative sampling strategies.

Ambient Pressure Laser Desorption—Chemical Ionization Mass Spectrometry for Fast and Reliable Detection of Explosives, Drugs, and Their Precursors

Fast and reliable information is crucial for first responders to draw correct conclusions at crime scenes. An ambient pressure laser desorption (APLD) mass spectrometer is introduced for this scenario, which enables detecting substances on surfaces without sample pretreatment. It is especially useful for substances with low vapor pressure and thermolabile ones. The APLD allows for the separation of desorption and ionization into two steps and, therefore, both can be optimized separately. Within this work, an improved version of the developed system is shown that achieves limits of detection (LOD) down to 500 pg while remaining fast and flexible. Furthermore, realistic scenarios are applied to prove the usability of this system in real-world issues. For this purpose, post-blast residues of a bomb from the Second World War were analyzed, and the presence of PETN was proven without sample pretreatment. In addition, the analyzable substance range could be expanded by various drugs and drug precursors. Thus, the presented instrumentation can be utilized for an increased number of forensically important compound classes without changing the setup. Drug precursors revealed a LOD ranging from 6 to 100 ng. Drugs such as cocaine hydrochloride, heroin, (3,4-methylendioxy-methamphetamine) hydrochloride (MDMA) hydrochloride, and others exhibit a LOD between 10 to 200 ng.

ChemInform Abstract: The Synthesis of Disperse and Cationic Dyes from Acid Dye Structures.

Abstract This paper is concerned with the conversion of some mono- and di-sulfonated naphthol azo dyes to disperse dyes suitable for poly(ethyleneterephthalate) fibers, and cationic dyes for cationic dyeable polyester and acrylic fibers. The chemical structure of these new dyes has been confirmed by 1H-NMR, FAB or DCI mass spectrometry, and in some cases by elemental analysis. Some fastness properties and absorption spectral data of both types of dyes are also reported, as well as an interesting limitation in the naphthalene-based acid dyes suitable for the described conversion.

Direct analysis of sterols from dried plasma/blood spots by an atmospheric pressure thermal desorption chemical ionization mass spectrometry (APTDCI-MS) method for a rapid screening of Smith–Lemli–Opitz syndrome

Here is proposed a rapid and sensitive method involving atmospheric pressure thermal desorption chemical ionization mass spectrometry (APTDCI-MS) for specific laboratory screening of the Smith-Lemli-Opitz syndrome (SLOS), an inherited defect of cholesterol biosynthesis. Biochemical findings in the blood of SLOS patients are low cholesterol (Chol), high 7- and 8-dehydrocholesterol (DHCs) levels and high DHCs/Chol ratios. The APTDCI proposed method is able to ionize sterols for qualitative and quantitative analysis directly from dried plasma/blood spots. Critical APTDCI parameters--desolvation gas flow and temperature--were optimized analyzing Chol, 7-DHC and cholesteryl stearate standards spotted onto a glass slide acquiring the full scan spectra in positive ion mode. Chol levels in dried plasma spots of unaffected controls (n = 23) obtained by the proposed method were compared with those of the enzymatic method (y = 0.9166x + 0.3811; r = 0.8831) while Chol and DHCs of SLOS patients (n = 9) were compared with the gas chromatography flame ionization detection (GC-FID) method (y = 0.8214x + 0.7388; r = 0.8288). The APTDCI-MS method is also able to differentiate normal from SLOS samples directly analyzing whole blood and washed red cells spotted on paper. In conclusion, the intrinsic analytical high-throughput of APTDCI-MS method for sterol analysis could be useful to screen SLO syndrome.

Rapid Differentiation of Tea Products by Surface Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry

Protonated water molecules generated by an ambient corona discharge were directed to impact tea leaves for desorption/ionization at atmospheric pressure. Thus, a novel method based on surface desorption chemical ionization mass spectrometry (DAPCI-MS) has been developed for rapid analysis of tea products without any sample pretreatment. Under the optimized experimental conditions, DAPCI MS spectra of various tea samples are recorded rapidly, and the resulting mass spectra are chemical fingerprints that characterize the tea samples. On the basis of the mass spectral fingerprints, 40 tea samples including green tea, oolong tea, and jasmine tea were successfully differentiated by principal component analysis (PCA) of the mass spectral raw data. The PCA results were also validated with cluster analysis and supervised PCA analysis. The alteration of signal intensity caused by rough surfaces of tea leaves did not cause failure in the separation of the tea products. The experimental findings show that DAPCI-MS creates ions of both volatile and nonvolatile compounds in tea products at atmospheric pressure, providing a practical and convenient tool for high-throughput differentiation of tea products.

Antileishmanial and antifungal acridone derivatives from the roots of Thamnosma rhodesica

Eight furanocoumarins, one coumarin and four acridone derivatives have been identified in the roots of Thamnosma rhodesica (Rutaceae). Rhodesiacridone, one of these acridone derivatives, is reported here for the first time. Its structure was elucidated by spectrometric methods including ESI-HR, EI, DCI mass spectrometry, 1H, 13C and 2D NMR experiments. This novel compound showed activities against the intracellular form of a human pathogen, the protozoan parasite Leishmania major. Two known acridone related compounds, gravacridonediol and 1-hydroxy-10-methylacridone, exhibited activities against the intracellular form of the same parasite and the fungus Cladosporium cucumerinum, respectively.

Genotypic Variation for Glycinebetaine in Sorghum

Glycinebetaine (GB) accumulation has been suggested to be an adaptive response to several abiotic environmental stresses. Genetic and metabolic studies of GB accumulation in maize (Zea mays L.) indicate that recessive alleles of a single locus are responsible for the phenotype of GB nonaccumulation. The present study was undertaken to determine whether a similar genetically determined range of GB levels exists in the related C4 species Sorghum bicolor (L.) Moench. In a preliminary analysis of 240 sorghum genotypes, sampled at the postflowering stage, total quaternary ammonium compound (QAC) levels in the betaine fraction of the flag leaves were found to range from as low as 0.1 μmol g−1 FW to as much as 33 μmol g−1 FW. Stable isotope dilution desorption chemical ionization mass spectrometry of six genotypes with high QAC levels and five genotypes with low QAC levels confirmed that this variation could be attributed almost exclusively to genetic variability for GB level. GB‐nonaccumulating sorghum genotypes were confirmed to be GB‐non‐accumulating in a second year of field‐testing, and in greenhouse studies under salinized and non‐salinized conditions. GB levels increased with seedling age and/or salinization in GB‐accumulating genotypes. Also, GB levels were highest in the youngest leaves of GB‐accumulating sorghum genotypes. This work shows that GB is the major QAC in sorghum, that genetic differences in GB accumulation exist in sorghum as they do in maize, and that the level of GB in GB‐accumulating lines is developmentally and environmentally regulated. A list of GB levels of publicly available lines of sorghum is also provided.

Occurrence of high molecular weight lipids (C 80+) in the trilaminar outer cell walls of some freshwater microalgae. A reappraisal of algaenan structure

The purified cell walls of mother cells (CWM) were isolated from three strains of trilaminar sheath (TLS)- and algaenan-containing freshwater microalgae Chlorella emersonii, Tetraedron minimum and Scenedesmus communis. The chemical structures of CWM and algaenans were investigated by means of tetramethylammonium hydroxide (TMAH) hydrolysis and tetramethylammonium hydroxide thermochemolysis. The compounds released were characterised by 1H and 13C-NMR, gel permeation chromatography and desorption chemical ionisation mass spectrometry. The results show that the outer cell walls of the microalgae are constituted, at least in part, of linear (poly)esters containing extremely long chain alcohol and acid moieties (up to C 80) and that algaenans are mainly composed of extremely long chain (di)carboxylic acids up to C 120. The present results which are in direct contrast to the previous three-dimensional architecture proposed for algaenans, led us to re-interpret the algaenan structure.

The renaissance of desorption chemical ionization mass spectrometry: characterization of large involatile molecules and nonpolar polymers

The present overview (1) presents a short historical perspective of desorption chemical ionization (DCI), (2) discusses the effect of the changes of some important experimental parameters, revealing which conditions minimize the occurrence of pyrolytic processes, (3) identifies the range of analytical problems where, in our own experience, DCI is more likely to provide unique performance, (4) outlines a possible mechanism for the overall DCI mass spectrometry (DCI-MS) analysis of large nonpolar molecules, and (5) presents several successful applications of DCI-MS, taken from our previous and recent research.

Titanium alkoxide complexes: condensed phase and gas phase comparisons.

The complex [Ti(2,4-dimethyl-2,4-pentanediolate)2]2 (1) has been synthesized from [Ti(OiPr)4] by transesterification with a stoichiometric amount of 2,4-dimethyl-2,4-pentanediol. We have characterized complex 1 in the solid state by single-crystal X-ray diffraction and in the gas phase by desorption chemical ionization mass spectrometry (DCI-MS). The structural and mass spectrometric data show complex 1 to be stable as a dimer in both the solid and gas phases. The retention of dimeric nuclearity in the gas phase sets complex 1 apart from other simple titanium alkoxide complexes [Ti(OiPr)4] and [Ti(OMe)4]4 that give rise to respective families of molecular ions in the DCI-MS experiment. The highest mass molecular ions for Ti alkoxide complexes in the gas phase may reveal the highest nuclearity that these complexes achieve in condensed phases. According to this interpretation the complex [Ti(OiPr)4] is principally dimeric in the gas phase and probably also in the pure liquid phase and should be represented by the formula [Ti(OiPr)4]2.

Metabolism of the ethanolamine-type antihistamine diphenhydramine (Benadryl) by the fungus Cunninghamella elegans.

Two strains of the filamentous fungus Cunninghamella elegans (ATCC 9245 and ATCC 36112) were grown in Sabouraud dextrose broth and screened for the ability to metabolize the ethanolamine-type antihistamine diphenhydramine. Based on the amount of parent drug recovered after 7 days incubation, both C. elegans strains metabolized approximately 74% of the diphenhydramine, 58% of this being identified as organic extractable metabolites. The organic extractable metabolites were isolated by reversed-phase high-performance liquid chromatography and identified by analyzing their mass and nuclear magnetic resonance spectra. Desorption chemical ionization mass spectrometry (DCIMS) with deuterated ammonia was used to differentiate possible isobaric diphenhydramine metabolites and to probe the mechanisms of ion formation under ammonia DCIMS conditions. C. elegans transformed diphenhydramine by demethylation, oxidation, and N-acetylation. The major metabolites observed were diphenhydramine-N-oxide (3%), N-desmethyldiphenhydramine (30%), N-acetyldidesmethyldiphenhydramine (13%), and N-acetyl-N-desmethyldiphenhydramine (12%). These compounds are known mammalian metabolites of diphenhydramine and may be useful for further toxicological studies.

The third-order non-linear optical response of the endohedral metallofullerene Dy@C 82

Dy@C 82 has been prepared by an efficient solvent extraction procedure and characterized by negative-ion desorption chemical ionization mass spectrometry and UV-VIS–near-IR absorption. Degenerate four-wave-mixing measurements on the CS 2 solution of Dy@C 82 were performed using 70 ps laser pulses at 0.532 μm. The magnitude of the second hyperpolarizability γ 1111 of the Dy@C 82 molecule was (3.0±0.5)×10 −30 esu at 0.532 μm. The resonant enhancement and the electron transfer from the trapped dysprosium to the C 82 cage are suggested to bring about its larger non-linear optical response relative to the empty fullerene. The experimental results are in good agreement with our calculations based on an extended Su–Schrieffer–Heeger model and the sum-over-state method.

Microstructure of alkoxy and alkyl substituted isocyanate copolymers determined by desorption chemical ionization mass spectrometry

Copolymers comprised of 3-(2-(2-methoxy)ethoxy)propyl isocyanate (monomer G) with 1-isocyanato-4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluorononane (monomer F) as well as copolymers of monomer G and n-hexylisocyanate (monomer H) were examined by desorption chemical ionization mass spectrometry (DCI-MS) to obtain information on the monomer distributions in the copolymers. The monomer distributions were deduced from the abundances of various protonated and ammoniated trimers in the ammonia DCI mass spectra using zero-order Markovian statistics. Both copolymers comprised of monomers G and F as well as monomers G and H were found to have random monomer distributions. This behavior is in contrast to copolymers comprised of monomers F and H whose dissimilar side chains resulted in non-random distributions.

Electron affinities and C60 anion clusters of certain bowl-shaped polycyclic aromatic hydrocarbons

The kinetic method is applied to the determination of the electron affinities (EAs) of the bowl-shaped polycyclic aromatic hydrocarbons (PAHs) dibenzo[a,g]corannulene (C28H14) 1 and diindenochrysene (C26H12) 2 using electron attachment desorption chemical ionization mass spectrometry (DCI-MS) and triple-quadrupole tandem mass spectrometry. The estimated EAs of 1 and 2 are 1.00±0.20 and 1.16±0.20 eV respectively. In an analogous experiment, loosely bound dimeric radical anions comprising C60 with 1 and C60 with 2 were generated in the gas phase by electron attachment desorption chemical ionization. The collision-induced dissociation of each of these cluster ions yields both the monomeric radical anions as products and yields calculated electron affinities of C60 of 1.20±0.20 eV (C60/1 dimer) and 1.24±0.20 eV (C60/2 dimer). These values are significantly different from the known electron affinity of C60 (2.65 eV) and support previous studies on electron-bound dimers comprising C6O and coronene [G. Chen, R. G. Cooks, E. Corpuz and L. T. Scott, J. Am. Soc. Mass Spectrom. 7, 619 (1996)] in showing that the dissociation of electron-bound dimers comprising C60 and reference PAHs is controlled by the electron affinity of a portion of the C60 surface, i.e. that a ‘local’ electron affinity of C60 is measured. The ‘local’ electron affinity value corresponds approximately to the electron affinity of the reference PAHs, C60 exhibiting an affinity for the ‘extra’ electron in the cluster which approximately matches that of its PAH partner. © 1997 by John Wiley & Sons, Ltd.

Block microstructural characterization of copolymers formed from fluorinated and non-fluorinated alkyl polyisocyanates using desorption chemical ionization mass spectrometry

Homopolymers and copolymers of 1-isocyanato-4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluorononane (monomer F) and n-hexylisocyanate (monomer H) were examined by desorption chemical ionization mass spectrometry (DCI-MS) to obtain information on the monomer distribution in the copolymers. Tandem mass spectrometry (MS/MS) was used to characterize ions generated by DCI in the mass spectrometer ion source; ammonia and isobutane were selected as chemical ionization (CI) reagent gases. The major peaks in the ammonia DCI mass spectrum of poly(4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluorononyl)isocyanate (poly ( F)) are protonated and ammoniated trimers. This result suggests that on pyrolytic degradation poly ( F) forms cyclic trimers as do alkyl isocyanate polymers. The isobutane DCI mass spectra display the characteristic alkene elimination sequence characteristic of poly( n-hexyl)isocyanate and poly(2,6-dimethylheptyl)isocyanate but with additional extensive fragmentation. The major fragment ion is the protonated monomer. The monomer distributions in copolymers comprised of monomer F and monomer H were deduced from the abundances of various protonated and ammoniated trimers in the ammonia DCI mass spectra using Markovian statistics. Both soluble and insoluble copolymer samples were isolated and found to have non-random monomer distributions. The soluble fraction is dominated by monomer H blocks while the insoluble fraction also contains a majority of monomer H blocks but relatively more monomer F blocks. This forms an example in the polyisocyanates, which hitherto exhibited only random copolymerization, of a non-living method of polymerization yielding a block microstructure for a mixture of two monomers with virtually identical polymerizable functions. Mass spectrometry offers information on chain microstructure which would be unavailable by other means.

A novel glycosphingolipid expressed in pig kidney: Gal alpha 1-3Lewis(x) hexaglycosylceramide.

Immunodetection of thin layer chromatograms of neutral glycosphingolipids of pig kidney cortex with a polyclonal antibody directed against the Gal alpha 1-3Gal determinant revealed several glycosphingolipids reacting with different intensities. A minor glycosphingolipid was isolated by preparative high performance thin layer chromatography. It was characterized as a type 2 hexaglycosylceramide with the following structure Gal alpha 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-Cer by fast atom bombardment- and desorption-chemical ionization-mass spectrometry, methylation analysis and hydrolysis with alpha-galactosidase followed by immunostaining with an anti-Lewis(x) monoclonal antibody. The proton NMR spectrum was found compatible with the proposed structure. Two other glycosphingolipids carrying the new determinant were partially characterized as an octa- and a branched-dodecaglycosylceramide. The expression of the Gal alpha 1-3 Lewis(x) determinant appeared to be developmentally regulated as it increased with age. The characterization of Gal alpha 1-3Le(x) in pig kidney indicates a new epitope capable of recognition by human natural antibodies in the context of xenotransplantation of pig organs to man. It also adds new members to the family of Le(x)-based glycolipids.

Sapidolide A: An unprecedented spherical carbocyclic lactone from Baccaurea sapida seed kernels: Is it a meroisoprenoid ?

A novel tetrahedrofurano-lactone meroisoprenoid (sapidolide A) 1 has been isolated from a tropical plant Baccaurea sapida, and its structure has been determined on the basis of DEPT, 1H 1H COSY, 1H 13C COSY, (+)-FABMS, low energy EIMS, and ion desorption chemical ionization mass spectrometry, and was confirmed by X-ray crystallography of its single crystal.

Fossil fuel characterization using laser desorption mass spectrometry: Applications and limitations

traditional gas-phase methods. The application and limitations of these techniques to model compounds and fossil-derived materials is discussed in this study. LD and MALDI mass spectrometry are increasingly used to detect intact molecular species, such as proteins with masses from 1000 to 100,000 amu and beyond.' MALDI is also being used for a few high molecular weight polymers.2 A good example, related to coal-type systems, is the report on lignin mass spectrometry by MALDI.3 Here the mass spectrum shows a wide molecular distribution of several hundred to larger than 16000, with the center of gravity of the distribution around 2600. The results are interpreted in terms of oligomeric lignin molecules. Thus, if there are indeed large molecular species in a polymeric content in fossil fuel extracts, MALDI is an attractive technique. We have previously reported laser desorption of coal extracts that show only low molecular weight ions (<ZOO0 amu).4-6 We compare LD with fast atom bombardment and desorption chemical ionization mass spectrometry, two other soft ionization techniques. All of these techniques produce similar data that differ only in minor details. We have used our two TOF mass spectrometers for coal analysis by MALDI, have carefully analyzed our data and the instrumental conditions and conclude that the bulk of coal material produces only low molecular weight ions (up to 2000 amu). In agreement with these reports, Hanky showed LD and MALDI data of pyridine extracts which produced a distribution of ions between 150 and 1500.7 In addition, field ionization mass spectrometry has found similar pattern in the low mass region.8 Recently, Herod et. aI9-'* have interpreted their LD and MALDI data in terms of high mass species being desorbed. We have presented alternate interpretations for these results.6 In our hands, LD or MALDI of coals and extracts do not show any reproducible ion intensity over mass 2000. The conditions whereby large molecular ions can be desorbed intact are very specialized. This paper will describe the scope and limitations of laser desorption and matrix-assisted laser desorption in time-of-flight mass spectrometers as applied to high molecular weight molecules, such as proteins and polymer systems. EXPERIMENTAL The coals used in this study are the Argonne Premium Coal Samples. The procedures for the pyridine extract of the Argonne Premium Coals have been reported previousl~.~ The laser desorption mass spectra and matrix-assisted laser desorption mass spectra were recorded on a linear time-of-flight mass spectrometer constructed at Argonne and a Kratos Kompact MALDI 111 linear/reflectron time-of-flight mass spectrometer. The spectra were produced by exposing the samples distributed as thin layer on a stainless steel sample holder to laser pulses from either a Nd:YAG or a

Negative‐ion mass spectrometry of sulfonylurea herbicides

AbstractSulfonylurea herbicides have been studied using negative‐ion desorption chemical ionization (DCI) mass spectrometry (MS) and DCI‐MS/MS techniques. Both [M  H]− and M−· ions were observed in the DCI mass spectra. The collisionally activated dissociation (CAD) spectra were characteristic of the structure of the herbicides examined. The fragmentation pattern was established based on the tandem mass spectra of the in situ deuterated sulfonylureas and on the comparison of the CAD spectra of sulfonylurea fragment ions with the CAD spectra of the ions derived from saccharin (o‐benzoic sulfimide) and methyl 2‐(aminosulfonyl)benzoate.