Brominated Tyrosine and Polyelectrolyte Multilayer Analysis by Laser Desorption Vacuum Ultraviolet Postionization and Secondary Ion Mass Spectrometry (original) (raw)
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Journal of Chromatography A, 2005
Atmospheric pressure photo ionisation has been evaluated for the analysis of brominated flame retardants and their related degradation products by LC-MS. Degradation mixtures obtained from the photochemical degradation of tetrabromobisphenol A and decabromodiphenylether were used as model systems for the assessment of the developed methodology. Negative ion mode gave best results for TBBPA and its degradation compounds. [M − H] − ions were formed without the need of using a doping agent. MS and MS/MS experiments allowed the structural identification of new TBBPA "polymeric" degradation compounds formed by attachment of TBBPA moieties and/or their respective cleavage products. In the case of polybromodiphenylethers, the positive mode provided M • + ions and gave better results for congeners ranging from mono-to pentabromodiphenylethers whereas for higher bromination degrees, the negative ion mode (providing [M − Br + O] − ions) was best suited. Under both positive and negative ionisation modes, the use of toluene as doping agent gave better results. Liquid chromatography-mass spectrometry by means of atmospheric pressure photo-ionisation was applied to the analysis of aromatic brominated flame retardants and their degradation products. This methodology proved to be particularly useful, for the characterisation and structural identification of some compounds which are not amenable to GC-MS, especially in the case of apolar "polymeric" degradation products of tetrabromobisphenol A investigated in this work.
Journal of the American Society for Mass Spectrometry, 2007
Bisphenol A diglycidyl methacrylate (Bis-GMA) was adsorbed onto or covalently bound to a porous silicon oxide surface. Laser desorption 10.5 eV postionization mass spectrometry (LDPI-MS) was previously demonstrated for surface analysis of adsorbed and surface bound Bis-GMA, but signal to noise levels were low and ion fragmentation was extensive. 7.87 eV postionization using the fluorine laser was demonstrated here for Bis-GMA. However, signal levels remained low for LDPI-MS of Bis-GMA as its ionization potential (IP) was only ϳ7.8 eV, near threshold for single photon ionization by the 7.87 eV fluorine laser. It is known that aromatic tagging of molecular analytes can lower the overall IP of the tagged molecular complex, allowing 7.87 eV single photon ionization. Therefore, Bis-GMA was also derivatized with several tags whose IPs were either below or above 7.87 eV: the tag with an IP below 7.87 eV enhanced single photon ionization while the tags with higher IPs did not. However, signal intensities were enhanced by resonant laser desorption for two of the derivatized Bis-GMAs. Intact ions of Bis-GMA and its derivatives were generally observed by 7.87 eV LDPI-MS, consistent with the formation of ions with relatively little internal energy upon threshold single photon ionization
Rapid Communications in Mass Spectrometry, 2014
RATIONALE: The worldwide generation of plastic electronic waste (e-waste) is reaching epic proportions. The presence of toxic brominated flame retardants (BFRs) within these materials limits their ability to be recycled, resulting in large amounts of e-waste reaching landfills. METHODS: Liquid extraction surface analysis mass spectrometry (LESA-MS) employing a chip-based nanoelectrospray coupled to a triple quadrupole mass spectrometer represents a novel control technology for directing e-waste streams for recycling. LESA-MS allows direct sampling and analysis of solid material, capable of detecting BFRs including polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBP-A), the two most common flame retardant additives currently in circulation. RESULTS: Authentic PBDE congeners and TBBP-A were deposited on glass and characterised by LESA-MS analysis. PBDEs are notoriously difficult to detect via electrospray; however, they were detected with ease by utilising a combination of nanoelectrospray and solvent doped with ammonium acetate. In situ detection of TBBP-A within plastic e-waste was also possible by performing LESA-MS on the surface of granulated material provided by a commercial waste depot. E-waste sample analysis was completely automated, with each sample analysed in less than 1 min. CONCLUSIONS: LESA-MS is fast, simple, and robust allowing unambiguous detection of a range of additives through tandem mass spectrometry. LESA-MS does not require dissolution of the solid matrix nor the sample to be present under vacuum and the use of separative techniques prior to analysis is not necessary.
Journal of Colloid and Interface Science, 2010
Infrared reflection absorption spectroscopy (IRRAS) was used to analyze the adsorption of the cationic surfactants n-dodecyl-, n-tetradecyl-, and n-cetyltrimethylammonium bromide (DTAB, TTAB and CTAB) at the air-water interface and to study their interaction with 1,2-dimyristoyl-d 54-sn-glycero-3-phosphocholine (DMPC-d 54) and 1,2-dimyristoyl-d 54-sn-glycero-3-phosphoglycerol (DMPG-d 54) Langmuir monolayers. From the Gibbs adsorption isotherms of the pure surfactants on 0.1 M NaCl as subphase the value of surface excess concentration C and the standard free energy of adsorption DG 0 was determined as a function of the interface coverage H. The conformational and orientational changes of the surfactant alkyl chains were followed by analyzing the frequencies of the antisymmetric and symmetric methylene stretching vibrational bands m(CH 2) during adsorption at the air-water interface. The interaction of the surfactants with lipid monolayers was also followed by IRRAS. Deuterated lipids were used to distinguish between hydrocarbon chains of the surfactants and the phospholipids. Thus, information on the conformational changes of the lipid molecules during incorporation of surfactant molecules into the lipid monolayer could be obtained. The absorbance values of the antisymmetric and symmetric methylene stretching vibrational bands (m(CD 2) and m(CH 2)) were used for the direct calculation of the surface partition coefficients P of the surfactants. The influence of the surfactant headgroup charge and its alkyl chain length on the incorporation into lipid monolayers is discussed.
Analytical Chemistry, 2015
The analysis of brominated flame retardants (BFRs) commonly relies on the use of gas chromatography coupled to mass spectrometry (GC-MS) operating in electron ionization (EI) and electron capture negative ionization (ECNI) modes using quadrupole, triple quadrupole, ion trap, and/or magnetic sector analyzers. However, these brominated contaminants are examples of compounds for which a soft and robust ionization technique might be favourable since they show high fragmentation in EI and low specificity in ECNI. In addition, the low limits of quantification (0.01 ng/g) required by European Commission Recommendation 2014/118/EU on the monitoring of traces of BFRs in food put stress on the use of highly sensitive techniques/methods. In this work, a new approach for the extremely sensitive determination of BFRs taking profit of the potential of atmospheric pressure chemical ionization (APCI) combined with GC and triple quadrupole (QqQ) mass analyser is proposed. The objective was to explore the potential of this approach for the BFRs determination in samples at pg/g levels, taking marine samples and a cream sample as a model. Ionization and fragmentation behaviour of fourteen
Polyelectrolytes as new matrices for secondary ion mass spectrometry
Journal of The American Society for Mass Spectrometry, 2005
Significant enhancements in ion yields in time-of-flight secondary ion mass spectrometry (TOF-SIMS) are observed when water-soluble analytes are mixed with a polyelectrolyte, e.g., poly(diallyldimethylammonium chloride) or poly(sodium 4-styrenesulfonate), and then deposited in the layer-by-layer method on a surface. This previously unobserved effect is demonstrated for 5-chloro-8-methoxyquinoline appended diaza-18-crown-6, 5-(2-aminoethoxy)methyl-5-chloro-8-methoxyquinoline appended diaza-18-crown-6, acridine, 9-anthracenecarboxylic acid, and ferrocenecarboxylic acid. By optical ellipsometry film thicknesses range from ca. 5–20 Å. X-ray photoelectron spectroscopy shows significantly less analyte in the polyelectrolyte-analyte films than in the neat analytes. However, TOF-SIMS generally shows significant enhancements in ion yields from the polyelectrolyte films compared with either the neat compounds or the compounds solubilized with acid or base and then dried on a surface. These significant enhancements in ion yields also appear to extend to analyte fragments and cationized molecular species. Some enhancement is also observed for dried droplets of analytes mixed with a polyelectrolyte on surfaces.
Adsorption of BSA onto radiation-crosslinked poly (AAm/HPMA/MA) terpolymers
Polymer Bulletin, 2003
The terpolymeric poly(acrylamide/2-hydroxypropylmethacrylate/maleic acid) ( A A d HPMAIMA) hydrogels in the rod form have been prepared by y-radiation of quaternary mixtures of acrylamide, 2-hydroxy propylmethacrylate, maleic acid and water. The hydrogels were used in experiments on swelling, diffusion and adsorption of bovine serum albumin (BSA) from aqueous BSA solutions. In the experiment of BSA adsorp-tion, the effect of initial concentration of BSA, content of MA, irradiation doses and medium pH on the adsorption efficiency of the hydrogel were studied. The binding of BSA onto AAm/HPMA/MA hydrogel corresponds to L4-type (Langmuir type with two layers) adsorption isotherms in the Giles classification system for adsorption of a solute from its solution The maximum adsorption capacity of monolayer adsorption (Q,,l,,J and the binding constant were found to be 1.27 ing BSA (g gel)" and 67.9 L (mg BSA).', respectively. The adsorption of BSA within AAm/€€PMNMA hydrogels increased with the increase in MA content in the AAm/HPMA/MA hydrogels. When the irradiation doses of hydrogel increased the adsorption of BSA also increased. The maximum adsorption of BSA was observed at pH 3.7. Significant amount of the adsorbed BSA (up to 95%) was eluted in the elution medium containing 1.0 M NaSCN at pH 8.0.
Mass Spectrometry of Synthetic Polymers
Analytical Chemistry, 2004
The aim of this review is to give a compact overview about the literature on mass spectrometry (MS) of polymers published during 2006/2007. The citations are drawn from SciFinder January 25, 2008, using the search terms "poly*" and "mass spectrometry" with restrictions to review and journal contributions in the English language including refined searches in Web of Science. More than 750 relevant papers, reviews, (1, 2) and historical summaries were published in these two years, demonstrating the importance of MS for polymer analysis. We were therefore forced to select the most important references. This is always a subjective decision and may not always represent the best choices. In contrast to the previous review in this series (5), which focused on MS principles, including matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF), electrospray ionization (ESI) TOF, TOF secondary ion mass spectrometry (SIMS), etc., in this paper, we categorize according to applications of MS for polymer analysis. Even this choice is arbitrary.