Vol. 53 No. 6
June, 2004
Yoshihisa Sei1,5, Kazuaki Shikii1, Shigeru Sakamoto1, Miki Kunimura1, Tatsuji Kobayashi2, Hiroko Seki1,5, Mitsuru Tashiro3, Makoto Fujita4,5 and Kentaro Yamaguchi1,5
1 Chemical Analysis Center, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-shi, Chiba 263-8522(Received 9 January 2004, Accepted 25 March 2004)
A direct solution analysis method, cold-spray ionization (CSI) mass spectrometry (MS), a variant of electrospray ionization (ESI) MS operating at low temperature (ca. -80~15°C ), allows a facile and precise characterization of labile organic species, especially those in which non-covalent bonding interactions are prominent. We have applied this method to investigations of the solution structures of many labile organic species, including unstable reagents and reaction intermediates, asymmetric catalysts, supramolecules, and even primary biomolecules. Remarkable analytical results were obtained for highly ordered supramolecules using the CSI method. While conventional ESI is not applicable to these compounds because of their instability to heat and/or air, CSI affords multiply charged molecular ions with many solvent molecules attached. An investigation of the constitution of Grignard reagents in solution is extremely challenging, but CSI-MS allowed us to identify one of the key structures in a THF solution. Large-scale aggregated chain structures of steroid compounds were observed in diluted solution by means of CSI-MS and PFG NMR. The crystal structures were determined by X-ray crystallography. It is suggested that the intermolecular hydrogen bonding observed in the crystal might be partly retained in diluted solutions. Recently, this method was adopted for investigating of the solution structures of primary biomolecules, such as nucleosides, amino acids, sugars and lipids, revealing singly charged Na+ adducts of large clusters (chain structures), presumably linked by non-covalent interactions, including hydrogen bonding and/or hydrophobic interactions. The principle of the CSI method and applications of the method to a wide variety of labile organic species and biomolecules including protein in solution are described.
Keywords : mass spectrometry; electrospray; cold-spray; cluster; non-covalent interaction.
Yoshiro Shiokawa1, Megumi Nakamura1, Harumi Maruyama1, Yoshiki Hirano1, Yasuyuki Taneda1, Masako Inoue1 and Toshihiro Fujii1
1 ANELVA Technix Corporation, 5-8-1, Yotsuya, Fuchu-shi, Tokyo 183-8508(Received 16 March 2004, Accepted 10 April 2004)
Ion Attachment Mass Spectrometry (IAMS) that can measure labile organic compounds without any fragmentation is reviewed. The ionization without fragmentation can be performed because a neutral molecule becomes an adduct ion by the attachment of Li+ with a small amount of energy of less than 2 eV by the Coulomb force. A third-body gas, such as 100 Pa N2, removes any excess energy of the adduct ion and makes it stable. Almost all organic compounds, except for simple structure ones, have a minimum detection amount of about 1 v/v ppb, 10-16 mol/s and linear response ranges of 6 figures. Because of “direct” (without GC) introduce contributed by fragment-free, IAMS can find heat-sensitive impurities, grasp thermal decomposition/desorption components, monitor exhaust gas from vehicles or process gases in industrial plants, and detect free-radical in plasma. It is difficult for conventional EI (electron ionization) to distinguish homologues due to the same fragment patterns. By contrast, we detected each molecular ion and some impurities in several kinds of phthalates with IAMS. Although acetal has not only similar fragment patterns of the compounds by EI, but also no molecular ion by CI, we could clearly measure it by IAMS. Molecular ion of a organometallic complex Cu(hfac)(tmvs), which has low binding energy of less than 1 eV, appeared in IAMS. A newly developed apparatus of IAMS for low-pressure sampling, small flow rate and high-speed response was suitable for measuring the vacuum process and thermal analysis, and for connecting to GC. Improving the present weak points, such as the detection limit, machine size and decreasing of sensitivities by moisture might lead to a evolution: realizing GC-IAMS for correct identification, “direct & real-time GC/MS” without GC and pretreatment, field measurements by a hand-carrier, and the measurement of unstable compounds in a flame/explosion/atmospheric environment.
Keywords : instrumentation; ion attachment; molecular ion; fragmentation; direct introduce.
Takafumi Hirata1, Yo-ichi Asada1, Tunheng Apinya1, Takeshi Ohno1, Tsuyoshi Iizuka1, Yumiko Hayano1, Masaharu Tanimizu2, Yuji Orihashi3
1 Laboratory for Planetary Sciences, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551(Received 13 January 2004, Accepted 12 February 2004)
This paper describes advances in elemental and isotopic ratio measurements that have been made with inductively coupled plasma mass spectrometry (ICP-MS) coupled with a laser-ablation sample introduction technique. Laser ablation utilizing UV light (frequency quadrupled to 266 nm or quintupled to 213 nm by a Nd-YAG laser, or an ArF Excimer 193 nm laser) is now the most widely used system because of its higher analytical precision and analytical capability to most of solid samples. However, even with UV lasers, serious elemental fractionation may occur during laser ablation, mainly due to differences in the element volatility. Therefore, the reduction of elemental fractionation during ablation is necessary for further precise and accurate elemental and isotopic analyses of trace elements. This is particularly the case for high quality-isotope data for age determination. In the field of geochemistry, great efforts have been made to obtain accurate Pb/U ratios, because 206Pb/238U ratios provide chronological information. The basic problem is that Pb/U results using conventional LA-ICPMS techniques show serious fractionations of the ratio over a prolonged measurement. The observed Pb/U ratio increases during the measurement because of the greater volatility of Pb. The Pb/U elemental fractionation is successfully reduced by an active focus technique, chemically assisted-laser ablation technique, or by soft-ablation technique. Moreover, recently developed techniques including signal stabiliser, a correction for the slow response of a Faraday amplifier and removal of isobaric interference by cool plasma conditions, will also expand the application fields and analytical accuracies of the LA-ICPMS technique. Outlines of these techniques are introduced.
Keywords : ICP-mass spectrometry; laser-ablation technique; isotope ratio; multiple collector; dating game.
Motoki Takahashi1, Zhanping Li1, Miyako Sekiya1 and Kichinosuke Hirokawa1
1 ULVAC-PHI Inc., 370, Enzo, Chigasaki-shi, Kanagawa 253-0084(Received 23 October 2003, Accepted 23 March 2004)
The regularity of fragment pattern appearance from metals as well as inorganic and organic compound surfaces in the Ga+ primary ion ToF-SIMS is discussed. Fragment patterns from metal surfaces indicate the possibility that metals form alloys with Ga during Ga+ primary ion irradiation and particle emission. In the case of inorganic compounds, a rule concerning the chemical bond between surface atoms, as follows, can be proposed. For an inorganic compound formulated like M-A, where the valence of cation M is +n, that of anion A is -p. The chemical composition of the appearing ToF-SIMS fragment is MxAy; the rules nx ≥ (py+1) for positive ion fragments and nx ≤ (py+1) for negative ones are satisfied. Here, M has a higher value of electronegativity and A has a lower value. For the fragmentation of some organic compounds, the chemical composition of appearing fragments can be inferred by considering the bond-dissociation energies between atoms in radicals of sample molecules.
Keywords : Ga+primary ion ToF-SIMS; fragment pattern appearance regularity; metals; inorganic and organic compounds.
Yasuyuki Hirakawa1, Masakazu Shimizu1 and Tsutomu Masujima1
1 Graduate School of Biomedical Sciences, Hiroshima Univeristy, 1-2-3, Kasumi, Minami-ku, Hiroshima-shi, Hiroshima 734-8551(Received 9 January 2004, Accepted 3 March 2004)
A novel mass spectrometry was developed for a direct dynamics analysis of molecules related to cells. We named the system “Video Mass Spectroscope”. This novel mass spectrometry enables us to observe the real-time dynamics of extracellular and intracellular molecules with only a single cell. In the experiments, bone marrow-derived mast cells were analyzed using matrix-assisted laser desorption/ionization (MALDI)-time-of-flight mass spectrometer. With the optimum matrix for MALDI and a suitable single-cell handling, the intracellular histamine was detected and it was found that its signal depended on the cell granulation and size. The results suggest that this new mass spectrometry has a potential to become a superior analysis tool for biomedical science.
Keywords : mass spectrometry; single-cell analysis; mammalian cell; video microscope; MALDI-TOF/MS.
Yasuhiro Nishimura1, Masaki Ohata1, Naoki Furuta1 and Takayuki Nabeshima2
1 Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo 112-8551(Received 14 January 2004, Accepted 10 March 2004)
In this paper, an ICP coupled with a three dimensional quadrupole mass spectrometer (ICP-3DQMS) was evaluated for lead isotopic measurements. The 3DQMS is a type of an ion trap mass spectrometer. These days, ICP coupled with a quadrupole mass spectrometer (ICP-QMS) is widely used for its advantages of high sensitivities and capability of isotopic measurements. However, the obtained precision (%RSD) of the isotopic measurements is limited to about 0.3%, because several isotopes are detected sequentially. On the other hand, because 3DQMS can trap several isotopes simultaneously, a precision of less than 0.1% (ca. 0.08%) could be achieved for 207Pb/206Pb and 208Pb/206Pb in this study. One drawback of 3DQMS is that there is a limitation on the number of total ions, that can be trapped. It was found that the value of [trapping time (ms)×concentration (ng/ml)] influences the accuracy and precision of isotopic measurements.
Keywords : inductively coupled plasma; ion trap; lead isotopic measurements; ICP-MS; ICP-3DQMS.
Kazuhiko Nishimura1,2, Toshiyuki Suzuki3, Eiji Katsura2 and Yutaka Itabashi1
1 Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1, Minato-cho, Hakodate-shi, Hokkaido 041-8611(Received 13 January 2004, Accepted 5 February 2004)
We have investigated reversed-phase high-performance liquid chromatography (HPLC) in conjunction with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) of the 9-anthrylmethyl ester derivatives of long-chain fatty acids. The positive ESI-MS gave a prominent [M+Na]+ (base peak) ion and a weak [M-RCOO]+ (m/z 191) ion, while the APCI-MS showed prominent [RCOO]- and [M-RCOO]+ (m/z 191) ions in negative and positive ion modes, respectively. By using these ions obtained by ESI-MS and APCI-MS, saturated and unsaturated fatty acids were identified satisfactorily. The detection limit (S/N=5) by selected ion monitoring (SIM) in negative ESI was 0.1 ng for a mixture of the fatty acid derivatives. The fatty acid compositions (peak area%) of a mink whale oil obtained by positive ESI-MS were in good agreement with those obtained by reversed-phase HPLC with fluorescence detection. The present HPLC/MS method for fatty acid anthrylmethyl esters can be utilized for the identification and quantification of complex fatty acid mixtures in biological samples.
Keywords : fatty acid; 9-anthryldiazomethane; 9-anthrylmethyl ester; reversed-phase HPLC/MS; ESI; APCI.
Seiji Uemura1, Kazuyuki Abe1 and Ryuichi Arakawa1
1 Department of Applied Chemistry, Faculty of Engineering, Kansai University, 3-3-35, Yamatemachi, Suita-shi, Osaka 564-8680(Received 13 January 2004, Accepted 9 March 2004)
The introduction reaction of carbon dioxide from 1,3-butadiene diepoxide to 1,3-butadiene dicarbonate was studied using catalysts of various alkali halides in supercritical carbon dioxide (scCO2). The reaction products were analyzed by electrospray ionization mass spectrometry (ESI-MS); also, the catalytic effect of alkali halides was examined. The results indicated that sodium iodide had the greatest catalytic effect among them. A tendency of the effect was considered based on the difference in the ion radius between alkaline metal and halogen, or the difference in the electronegativity of halogens. ESI-MS was a useful technique to analyze carbonate compounds formed by the scCO2 reaction.
Keywords : electrospray ionization mass spectrometry; supercritical carbon dioxide; 1,3-butadiene diepoxide; 1,3-butadiene dicarbonate; catalysis of alkali halides.
Masashi Yamaguchi1, Yasuo Mizooku1, Toshiyuki Osakai2, Takashi Kimoto3 and Ryuichi Arakawa1
1 Department of Applied Chemistry, Faculty of Engineering, Kansai University, 3-3-35, Yamate-cho Suita-shi, Osaka 564-8680(Received 13 January 2004, Accepted 12 April 2004)
Much attention has been focused on the strong antioxidant activity and antitumorigenic property of catechins extracted from green tea. However, not many studies on the oxidation process of catechins have been conducted. We employed an on-line electrochemistry/electrospray ionization mass spectrometry (EC/ESI-MS) technique to identify unstable oxidation products of catechins. We have succeeded in detecting dimer products formed by the electrolysis of (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate. EC/ESI-MS was a useful technique to study electrochemical oxidation process of antioxidants.
Keywords : catechins; dimers; mass spectrometry; electrospray ionization; microflow cell.
Masayoshi Ohmoto1, Shoji Okuno2 and Ryuichi Arakawa1,2
1 Department of Applied Chemistry, Kansai University, 3-3-35, Yamatecho, Suita-shi, Osaka 564-8680(Received 13 January 2004, Accepted 14 April 2004)
Nonylphenolpolyethoxylate polymers with different molecular weights were characterized by matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) and post source decay (PSD) experiments. The MALDI mass spectra indicated that the polymers have a repeated unit of (CH2CH2O) in the structure and contain small amounts of octyl- and decyl-phenolpolyethoxylate contaminants. The average molecular weights of the polymers obtained from the mass spectra were consistent with those of GPC measurements. Li+among alkali metal ions was found to be the best cationizing agent in PSD experiments. The PSD spectra suggested that the alkylphenol moiety in the end group of nonylphenolpolyethoxylate polymers contains alkyl structure of C6H13- group.
Keywords : matrix assisted laser desorption/ionization; post source decay; surfactant; alkylphenolpolyethoxylate; cationizing agents.
Miho Tanaka1
1 Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo, 108-8477(Received 14 January 2004, Accepted 14 April 2004)
In order to identify the chemical species in a solution just in the state, FAB-MS was employed among several kinds of mass spectrometry. In this paper, the author presents the process to establish the measurement using a FAB-MS, as well as the methods to measure the dissolved chemical species and the problems in this measurement. Furthermore, the author show the results of measurements of silica species for several seawater samples. Because the samples contained with the high concentration of silica, Muroto deep seawater and Toyama-bay deep seawater were examined. In the deep seawater, monomer, dimer, trimer, linear tetramer, cyclic tetramer, linear pentamer, cyclic pentamer, linear hexamers and cyclic hexamers were contained. Also the proton of the Si-OH group (silanol group) on silica was easily replaced by a sodium ion, calcium ion or potassium ion. All of the obtained chemical species from the deep seawater were the same as the ideal silicate species in sodium chloride and calcium chloride solutions, which were obtained from the pure salts, milli-Q water and silicagel. However, the relative peak intensity was distinguished in each sample. As one example, the linear tetramer and cyclic tetramer contain four numbers of atoms, but the structures and chemical characteristics in their solution were different. This difference reflects on the character of the solution and the solute, themselves. The peak intensity ratio of the linear tetramer and cyclic tetramer (329/311) were different between the surface water and deep seawater in Muroto and Toyama (Uodu). This shows that the peak intensity ratios of the linear tetramer and cyclic tetramer (329/311) should become a useful parameter to identify the characterization of the budget of the seawater.
Keywords : FAB-MS; silicate complex; chemical speciation; seawater.
Shinji Itoh1, Hitoshi Yamaguchi1, Toshiyuki Hobo2 and Takeshi Kobayashi1
1 National Institute for Materials Science, Materials Analysis Station, 1-2-1, Sengen, Tsukuba-shi, Ibaraki 305-0047(Received 20 November 2003, Accepted 7 February 2004)
We quantitatively determined Be, Al, Si, Ca, Mn, Fe, Ni, Cu, Zn, Zr, Ag, Cd, Sn La, Ce, Nd, Pb and Th concentrations in magnesium alloys using glow-discharge mass spectrometry (GDMS). The relative sensitivity factors in Mg (RSFX,Mg) of the analytes were evaluated using the ratios of the ion intensity for each element obtained from six standard samples of MBH SRMs. We selected 1 kV-2 mA as the optimum discharge parameter, and precisely examined the spectral interference related to both the main components and the discharge gas. For an experiment performed under these conditions, the observed interference of argide ions could be separated with 5000 (5% peak height) of the mass resolution. Of the RSF values that were measured by a Daly multiplier detector, Si, Cu, Sn, La, Ce and Nd were in accordance with published values, but Ca, Ni, Ag and Th greatly differed. The Faraday cup detector differs in sensitivity from the multiplier detector, and thus (RSFX,Mg) measured by each detector should be based on the concentration level of each element. The practical pure magnesium quantitative values produced by GDMS were in good agreement with those of chemical analysis. This indicates that we established a highly sensitive and quantitative analytical method to quickly and simultaneously determine the presence of many elements in magnesium alloys by using GDMS.
Keywords : relative sensitivity factor; magnesium alloys; glow-discharge mass spectrometry.
Yoshio Kumooka1
1 National Research Institute of Police Science, 6-3-1, Kashiwanoha, Kashiwa-shi, Chiba 277-0882(Received 15 December 2003, Accepted 22 February 2004)
Reactive pyrolysis-gas chromatography/mass spectrometry of a rosin-glycerol ester(RG) in the presence of tetramethylammonium hydroxide(TMAH), trimethylsulfonium hydroxide(TMSH), trimethl(a,a,a-trifluoro-m-tolyl)ammonium hydroxide(TMTFTH) or tetramethylammonium acetate(TMAAc) was studied. It was found that the most effective ester exchange reagent was TMAH and the optimum pyrolysis temperature was above 350°C. TMSH, TMTFTH and TMAAc were noneffective in the transesterification of RG.
Keywords : reactive pyrolysis-gas chromatography/mass spectrometry; abietic acid; rosin-glycerol ester; tetramethylammonium hydroxide(TMAH).
Kiwao Kadokami1, Kyoko Tanada1, Katsuyuki Taneda2 and Katsuhiro Nakagawa2
1 Kitakyushu City Institute of Environmental Sciences, Shin-ike 1-2-1, Tobata-ku, Kitakyushu-shi, Fukuoka 804-0082(Received 13 January 2004, Accepted 8 April 2004)
A novel GC/MS database for the simultaneous analysis of hazardous chemicals in the environment and food samples was developed. Since GC retention-time data and calibration curves other than mass spectra are registered into the database, an identification and determination of the chemicals in the database can be performed for a short time. By using n-alkanes as retention indices, under the same GC conditions, the retention times of the registered chemicals in samples were exactly predicted with an error for less than 3 seconds; by combining exact predict retention times and reverse searches, reliable identification was completed. Moreover, the registered substances also appeared in the sphere of 1% of the predicted retention times under different programmed temperature conditions and different carrier gas linear velocities. In an examination of the determination ability, by adjusting the GC inlet, the column, and the tuning conditions using the GC/MS performance standards, it was possible to produce a relative standard deviation of the determination values to be 20% or less, except for a part of high-polarity materials, such as pentachlorophenol and benzidine, which are very easy to adsorb on a column. More than 90% of the chemicals in the database could be detected at 100 or less pg, and it exhibited a practically sufficient sensitivity. From these results, it was confirmed that more than 1000 hazardous chemicals can be simultaneously determined without standards by the database system. The database, therefore, can be applied to evaluate the overall safety of environment media and foodstuff.
Keywords : GC/MS; database; simultaneous analysis; hazardous chemicals.
Atsuko Shinohara1, Momoko Chiba1, Masao Kondo2, Fadi R. Abou-Ahakra3, Heather Walker3, Kyoko Kobayashi4 and Yutaka Inaba1
1 Dept. Epidemiology and Environmental Health, Juntendo Univ. School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421(Received 29 January 2004, Accepted 26 April 2004)
The analytical conditions for the simultaneous determination of arsenic(As) compounds in human urine were examined using high-performance liquid chromatography (HPLC) with an ion-exchange column combined with a hexapole collision cell inductively coupled plasma mass spectrometer. The addition of 0.1 mM EDTA to the mobile phase of HPLC (a mixture of 10 mM NH4NO3 and 0.05% HNO3, pH 3.1) was necessary for good reproducibility of the peaks. The five As species {As(V), monomethylarsonic (MMA), dimethylarsinic (DMA), As(III), and arsenobetain (AB)} were separated within 14 min, however, arsenocholine(AC), trimethylarsine oxide (TMAO) and tetramethylarsonium (TeMA) were not individually separated but eluted together at about 40 min of retention time. This method was applied to urine samples from 8 male Japanese. Although As(V), MMA, DMA, and AB were detected in all urine samples, the relative amounts of these compounds were different depending on the person. The order of concentrations of arsenic compounds in urine from 4 person were AB>DMA>MMA>As(V), but those in the other samples were AB≅DMA or AB<DMA, suggesting the individual difference in the eating habits of sea foods.
Keywords : Arsenic species; speciation; human urine; HPLC/ICP-MS; hexapole collision cell.
Masaru Terada1, Tatsuo Shinozuka2, Einosuke Tanaka3, Takeshi Hayashi4, Katsuya Honda3, Ryoji Matoba4 and Kunihiko Kurosaki1
1 Department of Legal Medicine, School of Medicine, Toho University, 5-21-16, Oomorinishi, Oota-ku, Tokyo 143-8540(Received 14 January 2004, Accepted 10 March 2004)
In this study, we considered a sensitive method for the determination of triazolam from forensic case samples using gas chromatography tandem mass spectrometry. The discrimination of the etizolam and triazolam mixture was usually very difficult because of the same molecular weight and similar mass spectra. However, both drugs were identified by GC/NICI/ion trap tandem mass spectrometry. The detection limits of GC/NICI/ion trap tandem mass spectrometry for triazolam from serum and urine were ca. 2 ng/ml and 1 ng/ml, respectively. The determination of triazolam in human serum and urine by GC/NICI/ion trap tandem mass spectrometry provided a highly sensitive and high-specificity method. It is expected that this method will be applicable to the determination of drugs in forensic biological materials.
Keywords : triazolam; etizolam; tandem mass spectrometry; GC/NICI/MS/MS; serum; urine; blood.
Liwei Sun1, Hiroaki Sato1, Masaki Torimura1, Hiroaki Tao1, Tomoyoshi Shintani2
1 Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), 16-1, Onogawa, Tsukuba-shi, Ibaraki 305-8569(Received 21 January 2004, Accepted 18 March 2004)
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was applied to the rapid discrimination of four lactic acid bacteria (Lactobacillus acidophilus, Lactococcus lactis subsp. hordniae, and two strains of Lc. lactis subsp. lactis). Specific biomarker peaks generated from intact bacteria cell were observed on the mass spectra over the range m/z 4000~12000. High reproducibility for the relative peak intensities between three culture plates under the same experimental conditions was confirmed by analysis of variance (ANOVA). The growth temperature strongly affected the peak distribution of the biomarkers, whereas the difference in the culture media (MRS and LB media) gave similar mass spectra. Under the optimized conditions, four lactic acid bacteria with different genus, species, or strains could be discriminated.
Keywords : MALDI-MS; lactic acid bacteria; rapid discrimination.
Hiroaki Sato1,3, Hajime Ohtani1, Shin Tsuge1, Iwao Tsuda2 and Shigeru Suetomo2
1 Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya-shi, Aichi 464-8603(Received 21 January 2004, Accepted 8 April 2004)
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was applied to the structural characterization of rosin-glycerin ester and rosin-resol resin reactant as the model compounds of rosin-modified phenol resin. As for the rosin-glycerin ester sample, sodium cationized di- and triglycerides of the rosin acids were mainly observed as major products, whereas those of monoglycerides were scarcely observed on the MALDI mass spectrum. Considering the isotope distribution, the composition of the rosin acid in the glyceride was estimated as abietic acid/dehydroabietic acid=ca. 70/30, whereas that in the original rosin acid was ca. 95/5. This fact demonstrated that a considerable amount of abietic acid was transformed to the dehydroabietic acid structure. On the other hand, as for the rosin-phenol resin reactant sample, resol resin oligomers having rosin acids at both terminals were observed as the main components in the range of the degree of polymelyzation n=1 to 8, while those having a rosin acid at one terminal side were also observed as minor components mainly at a lower mass range under m/z 1000. Moreover, the detailed distribution among the observed ions suggested that the dehydration in the abietic acid also fairly took place during the reaction between the rosin acids and the resin.
Keywords : MALDI-MS; rosin-modified phenol resin; rosin-glycerin ester; rosin-phenol resin reactant; structural characterization.
Koichi Usukura1, Tamio Seko2 and Nobuhiko Onda1
1 PerkinElmer Japan Co. Ltd., 2-8-4, Kitasaiwai, Nishi-ku, Yokohama-shi, Kanagawa 220-0004(Received 9 January 2004, Accepted 20 March 2004)
The brominated fire retardants added to polymer resin are getting attention concerning a risk of the toxicity to human health and the environment. Specifically, decabromodiphenylether (DeBDE) and decabromobiphenyl (DeBB) are restricted for use by the European Directives. The molecular weight of DeBDE is 960, and it is difficult to acquire the full spectrum by commercial quadrupole GC/MS, and none has been reported, except for a paper by the present authors. This study examined the use of a high mass quadrupole GC/MS for the simultaneous detection of polybromodiphenylethers (PBDEs) by electron impact ionization (EI) and the negative chemical ionization (NCI). The typical detection limit of DeBDE was found to be 5.2 to 53 pg/ml by EI and 2.4 to 19 pg/ml by NCI. The achieved recovery was 96.9 to 105%. The developed method was applied to industrial samples. Other brominated fire retardants were also found.
Keywords : polybromodiphenylethers; decabromodiphenylether; fire retardant; quadrupole-GC/MS; electric household appliance.
Ritsuko Hara1, Chikako Sakabe2, Tomohiko Ohwada3 and Kentaro Yamaguchi1
1 Chemical Analysis Center, Chiba University, 1-33, Yayoicho, Inage-ku, Chiba-shi, Chiba 263-8522(Received 9 January 2004, Accepted 23 March 2004)
In an exact mass measurement by fast-atom bombardment mass spectrometry (FAB-MS), a couple of calibrant ion peaks were selected to calibrate the target ion. The target ion peak should be located between these two calibrant ion peaks on the mass spectrum. Although polyethyleneglycols, cecium iodide and “Ultramark” have been used as promising calibrants, it is generally difficult to obtain the desired ion intensity and mass number using these reagents. In this report we describes the optimization of the internal calibrant in both the positive and negative ionization modes. As a result, the effective ratio of the mixed calibrant was derived. The intensity of the ion signal was also improved by using these mixtures. The optimized calibrant expands the mass region from m/z 600 to 3000 while maintaining with even higher precision.
Keywords : mass spectrometry; high resolution; internal calibrant; ultramark; poly ethyleneglycol.
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