Authors:M. A. Fahmey, M. A. Zayed, and H. G. El-Shobaky
This paper describes the use of the mass spectrometry (MS), thermal analyses (TA) and other physico-chemical methods to investigate
the structure of two newly synthesized phenolic-iodine derivative polymeric products. These two products are formed as a result
of redox-interaction of adrenaline hydrogen tartrate (AHT, I) with iodate (IO-3) and periodate (IO-4). The characterization of the two products were achieved satisfactorily by using the above tools and their proposed general
formulae, were found to be C52H67O36N4I (AHT- IO-3, II) and C26H34O18N2I2(AHT- IO-4, III). The fragmentation behavior of the main compound (AHT) in MS and TA (TG and DTA) techniques was investigated and compared.
The results obtained were used to explain the fragmentation of the products AHT- IO-3and AHT- IO-4in mass spectrometry and thermal analyses techniques. The stabilities of different fragments were discussed. The results indicate
that the two techniques are supporting each other in which the mass spectrometry provides the structural information in gas
phase while the thermal analyses provides the quantitative fragmentation in the solid-state.
Three interesting new compounds formed as a result of phenols-iodine redox reactions were investigated by mass spectral fragmentation (MS) and thermal analyses (TA) as well as some other physicochemical methods as microanalysis and infra-red spectroscopy to elucidate their structures. The characterization of the compounds was satisfactorily achieved by using the above analytical tools and their proposed general formulae, were found to be C24H15O8I (PC-IO
), C24H14O12 I2 (PG-IO
) and C12H8O6I2 (PG-IO
).The fragmentation pathways of PC-IO
have been examined using electron ionization (EI) mass spectrometry in comparison with thermal analyses (TG and DTA). Both decomposition modes were investigated, and the fragmentation pathways were suggested. The combined application of mass spectrometry and thermogravimetry (MS and TG) in the analysis of the products allowed the characterization of the fragmentation pathway in MS.The major pathway in both techniques of PC-IO
is due to the loss of CHO followed by CH3I+2H2O. It is due to the loss of 2H2O followed by the loss of 2CH3I for PG-IO
. While for PG-IO
it is related to the loss of 2H2O followed by loss of 2CH3I molecule stepwise. Different stabilities for initial products and some fragments are discussed.
Authors:T. Streibel, A. Fendt, R. Geißler, E. Kaisersberger, T. Denner, and R. Zimmermann
The combined analytical methods of thermal analysis and mass spectrometry have been applied in form of a newly developed prototype
of a thermogravimetry — single photon ionisation time-of-flight mass spectrometer coupling (TG-SPI-TOFMS) to investigate the
molecular patterns of evolved gases from several biomass samples as well as a crude oil sample. Single photon ionization (SPI)
was conducted by means of a novel electron beam pumped argon excimer lamp (EBEL) as photon source. With SPI-TOFMS various
lignin decomposition products such as guaiacol, syringol and coniferyl alcohol could be monitored. Furthermore, SPI allows
the detection of aliphatic hydrocarbons, mainly alkenes, carbonylic compounds such as acetone, and furan derivatives such
as furfuryl alcohol and hydroxymethylfurfural. More alkaline biomass such as coarse colza meal show intense signals from nitrogen
containing substances such as (iso-)propylamine and pyrrole. Thermal degradation of crude oil takes place in two steps, evaporation
of volatile components and pyrolysis of larger molecular structures at higher temperatures. Due to the soft ionisation, homologue
rows of alkanes and alkenes could be detected on basis of their molecular ions.
The obtained information from the thermal analysis/photo ionisation mass spectrometry experiments can be drawn on in comparison
to the investigation of the primary products from flash pyrolysis of biomass for production of biofuels and chemicals.
Authors:S. Kravić, N. Marjanović, Z. Suturović, J. Švarc-Gajić, Z. Stojanović, and M. Pucarević
The fatty acid composition and trans fatty acid (TFA) content of Serbian shortenings were determined by capillary gas chromatography-mass spectrometry. The saturated, cis-monounsaturated and polyunsaturated fatty acid contents were within the ranges of 16.0–89.0, 4.9–41.9 and 0.0–23.2% of total fatty acids, respectively. Among the saturated fatty acids, palmitic acid (4.8–48.7%) was dominant and its higher amount indicates that palm oil was the major contributor in the shortening manufacturing. The content of total trans fatty acids ranged from 0.0% to 48.7% of total fatty acids and the mean was 27.4%. Trans 18:1 isomers were the major group of TFA present in analysed samples, representing 94.2% of total trans isomers. The content of all 18:2 trans isomers ranged from 0.0% to 3.6% of total fatty acids. Among thirty-four analysed samples only six contained low level of TFA (0.0–3.1%) while the rest contained very high amounts of TFA (10.2–48.7%) which clearly indicate that partially hydrogenated vegetable oils are still the major raw materials used in the production of shortenings in Serbia.
Authors:K. Pápai, M. Budai, K. Ludányi, I. Antal, and I. Klebovich
The quantitative analysis of antibiotics in different matrices is of increasing importance in in vitro studies of food-drug interactions in the drug-development process. Our objective was to develop a new, rapid and simple solid-phase extraction method without protein precipitation followed by high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) for analysis of ciprofloxacin in low- and high-fat milk. The HPLC-MS method (a single-quadrupole mass spectrometer equipped with an electrospray ion source was used as detector) was validated using a quinolone derivative, aripiprazole, as internal standard. A C8 column and gradient elution with 0.02 m ammonium acetate solution (pH 2.5) and acetonitrile mixtures (flow rate 0.5 mL min−1) were used for HPLC separation. Various modes of detection (diode-array detection and MS detection in scanning and selected-ion monitoring modes) were compared for selectivity and sensitivity of quantitative analysis of ciprofloxacin. Use of selected- ion monitoring resulted in a 1600:1 signal-to-noise ratio which can be successfully applied to milk matrices resulting in a lower limit of detection of 0.4 ng mL−1 and a lower limit of quantification of 4.0 ng mL−1. Recovery was 99.06 ± 0.15 and 98.57 ± 0.14% for low- and high-fat milk, respectively. The method enables analysis of the free, biologically available, amount of ciprofloxacin in in vitro simulation of milk-ciprofloxacin interaction studies.
Authors:A. Tonamo, I. Komlósi, L. Varga, M. Kačániová, and F. Peles
, 2009; Becker et al., 2014 ). Similar to the emergence of polymerase chain reaction, the backbone of modern molecular biology, matrix-assisted laser desorption ionisation–time of flight massspectrometry (MALDI-TOF MS) has also become a paradigm
Authors:A. A. Marchetti, T. A. Brown, C. C. Cox, T. F. Hamilton, and R. E. Martinelli
Accelerator mass spectrometry (AMS) is a sensitive and robust technique typically applied to the quantification of long-lived radioisotopes in samples too small to be decay-counted. AMS is characterized by a high rejection of interferences and a low susceptibility to matrix components, which reduce the demands on sample preparation chemistry. At Lawrence Livermore National Laboratory (LLNL), Center for Accelerator Mass Spectrometry (CAMS), we have developed an AMS capability for the measurement of actinide concentrations and isotopic ratios. To date, this capability has been primarily devoted to the measurement of 239Pu and 240Pu in bioassay and environmental samples including soils, sediments, waters, and human urine. For these analyses, a known amount of 242Pu is added to the samples as a reference isotope for normalization. Measurements of standard and intercomparison samples have shown that quantification is accurate and precise from at least 106 to 1011 atoms/sample. Recently, the ratios of 240Pu, 241Pu, 242Pu, and +Pu to intrinsic 239Pu have been successfully measured in soil samples from nuclear test sites. In addition, initial measurements of U and Np isotopes have yielded results consistent with the Pu measurements with respect to sensitivity, accuracy, precision, and linear range.
foods. At present, the determination methods of acrylamide in food mainly include gas chromatography (GC) [ 14–16 ], gas chromatography-massspectrometry (GC-MS) [ 17–19 ], high performance liquid chromatography (HPLC) [ 20–22 ] and high performance
Authors:Mohamed A. Zayed, M. F. Hawash, M. A. Fahmey, and Ali M. M. El-Gizouli
structure of ibuprofen and numbering system
Rapid advances in biological sciences have led to an increased demand for the chemical and structural information about biological systems. The massspectrometry (MS) plays a