The effect of trimethylsilyl (TMS) derivatives, which have been long and widely used especially in gas chromatography/mass spectrometry (GC/MS), was examined with fast atom bombardment (FAB) mass spectrometry. In order to investigate what kind of information can be obtained from FABMS of TMS derivatives of biologically related compounds, FABMS and FAB MS/MS (tandem mass spectrometry) of TMS derivatives of compounds such as 2'-O-methyladenosine, 3'-O-methyladenosine, guanosine, uridine and some amino acids were studied. As a result, FABMS spectra of trimethylsilylated compounds gave molecular ion peaks showing that the TMS groups attached to alcoholic hydroxy groups remained intact, while the TMS groups attached to NH, SH, COOH and amide groups were labile and partly removed. It was concluded that FABMS spectra of trimethylsilylated substances have the advantage of not only determining the total number of active hydrogens, but also differentiating groups such as OH, NH, SH, CONH and COOH. It was also proved that FAB mass spectrometry of TMS derivatives of biologically related compounds are very useful for structural analysis of the native compounds. Here we have mainly used 3-nitrobenzyl alcohol (3-NBA) as the matrix for FABMS because of its solubility in the trimethylsilylation reaction mixture.

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This paper describes advances in isotopic measurements that have been made with an inductively coupled plasma source magnetic sector multiple collector mass spectrometer (MC-ICP-MS) and presents results of new experiments aimed at further evaluating the instrumental capability as well as the correction technique for the mass discrimination effects. The ability to correct for the mass discrimination effect using a second element of similar mass and very high sensitivity for elements that are otherwise difficult to ionize gives this instrument major advantages over other conventional techniques for isotopic measurements.
The isotopic data obtained by MC-ICP-MS clearly demonstrate potential as a new technique to produce precise and reproducible isotopic data for the elements that are difficult to measure by thermal ionization mass spectrometry (TIMS).

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To overcome some problems of the argon ICP-MS, a helium ICP-MS device was developed using an enhanced vortex flow torch. Effects of sampler-skimmer distance on the pressure in the 2nd stage and on the ion signal intensities were studied and it was found that both the Mach disk position and the most suitable position for analysis are 7 mm. No background spectral peak was found at m/z values over 32 except for copper from the sampler. Ion intensities of neon and krypton that were low in sensitivity in argon ICP-MS due to their high ionization energies were as much as 36 and 24 times greater in He ICP-MS, respectively.

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In the source apportionment of suspended particulate matter (SPM), not only the average composition, but also the compositional distribution within an SPM particle is important. However, it is difficult to obtain both kinds of data with one analytical technique. Electron probe microanalysis (EPMA) is suitable for average compositional analysis, while gallium focused ion beam secondary ion mass spectrometry (Ga FIB SIMS) gives us the compositional distribution of a particle. Therefore, the combination of EPMA and Ga FIB SIMS is desirable for obtaining detailed information on a particle. However, two problems must be overcome to make this combination practicable: avoidance of charge-up and identification of the same particle in separate microscopic fields. We proposed a procedure to overcome these problems by using a Ag membrane filter and Au index grid. This procedure was applied to the analysis of SPM particles collected near a traffic road. As a result, mineral origin particles in addition to a lot of soot were found in EPMA analysis, and Ga FIB SIMS clearly showed the existence of minor elements and their compositional distribution on the single particle level.

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Nonmetallic inclusions unfavorably influence the quality of steel but their origin and generation process are not yet understood. The development of methods for the characterization of each inclusion particle is required. By employing a gallium focused ion beam (Gat⁺-FIB) as the primary ion beam in secondary ion mass spectrometry (SIMS), particle analysis with high spatial resolution is easily achieved. We analyzed individual nonmetallic inclusion particles in Al-deoxidized and Ti-denitrified low carbon steel (Interstitial atom-Free steel: IF steel) by electron probe microanalysis (EPMA) and submicron SIMS. From the EPMA measurements followed by cluster analysis, the inclusion particles were classified into 3 clusters. We carried out shave-off analysis for the typical particle in each cluster. From the shave-off profile, the composition and inner elemental distribution were obtained. From these analyses, the generation process of nonmetallic inclusions in IF steel was clarified.

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Charged particles such as ions and electrons with keV order kinetic energy are important as probes and signals for surface analyses. Many detection systems have been developed to measure two-dimensional distribution of particles. However, the capabilities of solid-state area detector are not sufficient for quantitative analysis of the charged particles; although the solid-state imager such as the charge coupled device has been successfully developed to detect photons in optical spectroscopy. This paper discusses the performance and characteristics of a novel solid-state imager for charged particles, which is useful for charged particle detection in such procedures as mass spectrometry and electron microscopy.

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A method of increasing the detection response by acetyl-derivatization on atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) has been investigated. By acetylation on compounds having primary alcohol, primary amine and phenolate, it was found that the detection responses of their acetylated forms were increased by 2 to 5 fold over their intact forms. This suggests that acetyl-derivatization was an effective method of increasing response on APCI-MS for compounds having these groups. A possible reason is that acetylation caused increased proton affinity (PA). So, PA should be well considered when trying to increase the response on APCI-MS by derivatization. This acetyl-derivatization method seems promising for increasing the response on LC/APCI-MS.

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A computer program for identification of polymer additives by MS spectral data has been developed. Some empirical equations for calculating existence probabilities of certain additives are presented. This method seems to be applicable to the identification of polymer additives in various polymer compounds.

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A method for the determination of trace levels of Pt in biological materials by ICP-MS was studied. A matrix effect caused by high concentrations of NaCl markedly reduced the ion intensity of Pt. Using In as an internal standard compensated for the matrix effect in NaCl solution and bovine serum. For the bovine serum samples (10-, 100- fold dilution and acid-digestion followed by 10-fold dilution), the In internal standard method provided an accurate value of 1 ng ml^-1 of Pt added to the serum. A polyatomic ion interference by HfO on the Pt determination was observed in the analysis of NIES Human Hair reference material, which contains a relatively high level of Hf. The proposed method was applied to the determination of Pt in liver, kidney and ascites fluid of a cisplatin administered rat. The analytical values were close to those obtained by ultrasonic nebulization-ICP emission spectrometry.

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Liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) combined with a column switching technique was applied to the quantification of serum dehydroepiandrosterone sulfate (DHEA-S). Human serum samples were directly injected into the sample preparation column (TSK precolumn BSA-ODS), and then DHEA-S was separated by an analytical column of Inertsil ODS-2. DHEA-S was detected on-line by a Hitachi M 1000 mass spectrometer equipped with an APCI interface. For the detection of DHEA-S, the drift, focus, and multiplier voltages were set at -70 V, -120 V and 2.4 kV, and the vaporizer and the desolvation temperatures were set at 280 and 399°C, respectively. The applied potential for the needle electrode was -10 μA. The detection limit of DHEA-S was 10 ng on-column with a signal-to-noise ratio of 3. The calibration curve was linear over the range of 50300 ng on-column. The proposed method was successfully developed for the determination of DHEA-S in human serum.

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A microanalytical LC/MS method for the determination of brassinosteroids as their boronates has been developed. Under reversed-phase liquid chromatographic conditions the brassinolide boronates, formed by naphthaleneboronic acid, m-aminophenylboronic acid or dansylaminophenylboronic acid, have been analyzed using atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) methods. The effects of additives to the liquid chromatographic mobile phase on the sensitivity for detection of the boronate were examined. A detection limit of 25 picogram (signal-to-noise ratio 3) of brassinolide as naphthaleneboronate was attained in the selected-ion monitoring (SIM) mode with electrospray ionization, and that of 2.5 picogram (signal-to-noise ratio 4) for the naphthaleneboronate derivative was attained in the multiple reaction monitoring (MRM) mode with ESI. The LC/MS analysis of these boronate derivatives could be very useful for trace analysis of brassinosteroids.

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GD-MS analysis of nickel-based heat-resisting alloys has been performed using a VG 9000 glow discharge (GD) mass spectrometer. Concentrations of not only alloying elements (Al, Si, Ti, V, Cr, Mn, Fe, Co, Cu, Y, Nb, Mo and W) but also trace elements (B, C, Mg, P, S, Zn, Ga, As, Zr, Cd, Sn, Sb, Te, Pb and Bi) were successfully determined in disk shaped samples. The examination of spectral interference confirmed the following. The influence of manganese argide (⁵⁵Mn⁴⁰Ar⁺) on the ion beam intensity of ⁹⁵Mo⁺ was negligible because manganese content of the alloys is usually less than 1 mass%. Mass spectra of ³¹P⁺ and ³²S⁺ may be affected by the spectral interference of ⁶²Ni²⁺ and ⁶⁴Ni²⁺, respectively, due to the matrix element. However, these ion species were sufficiently separated at the mass resolution 5000 (m/Δm, at 5% peak height) used in this study. Relative sensitivity factors (RSFs) were determined by analyzing standard reference materials: JAERI CRMs, a NIST SRM, a BS CRM, BCS CRMs and the alloys prepared in our Institute. The average RSF-values obtained for Ni=1 were 0.436 for Al, 0.826 for Si, 0.281 for Ti, 0.375 for V, 1.480 for Cr, 1.122 for Mn, 0.754 for Fe, 0.653 for Co, 3.321 for Cu, 0.303 for Y, 0.436 for Nb, 0.862 for Mo, 0.935 for Ta and 1.052 for W. The analytical accuracy (σ_d) obtained was comparable to that of FP-XRF analysis, except for chromium and iron determinations. Relative standard deviations (RSDs) of five replicate measurements were within about 2.5%, except for phosphorus (P;0.003 mass%, RSD; 3.31%) and sulfur (S; 0.005 mass%, RSD; 3.08%). GD-MS analytical values for ODS MA6000 alloy were obtained using a RSF correction program, and the values were in good agreement with those obtained by FP-XRF and by chemical analysis.

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A highly sensitive and specific liquid chromatographic/tandem mass spectrometric method was developed for the determination of 26, 26, 26, 27, 27, 27-hexafluoro-dihydroxy-vitamin D₃, a new fluoro analogue of 1, 25(OH)₂-vitamin D₃. It was found that this compound gave an acetic acid-adducted ion with high intensity when the mobile phase contained acetic acid. By optimizing the mobile phase composition in the liquid chromatography system in obtaining the highest response of the adduct ion, this compound in serum was determined down to as low concontration as 0.1 pg/ml, following only deproteinization by acetonitrile and purification on solid phase cartridge. It was recognized that the present assay method has sufficient precision, rapidity and simplicity in execution, and enables us to carry out the determination of very low concentration of this compound in clinical studies for humans.

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A method for automated simultaneous analysis of 9 kinds of preservatives such as sorbic acid, dehydroacetic acid, benzoic acid, 2, 6-t-butyl hydroxyanisole (BHA) and five p-hydroxybenzoates in foods was developed using a gas chromatograph/mass spectrometer (GC/MS) with an automated sample preparation instrument. The use of the solid phase extraction (SPE) method utilizing a polymer based cartridge and pH adjustment of sample (pH=3.5) in the pretreatment made it possible to recover successfully ppb levels of sample. Recoveries (%) and repeatabilities {n=6, relative standard deviation (RSD, %)} of preservatives in fruit vinegar were as follows; sorbic acid, 86% (RSD=1.6%) ; benzoic acid, 76% (RSD=8.0%); dehydroacetic acid and p-hydroxy-benzoates, more than 90% (RSD, less than 8.3%). The detection limits of the method using selected ion monitoring (SIM) were 0.1 ppb. Nine kinds of preservatives in foods (soy sauce, sauce, wine and vinegar) were determined by the proposed method. For example, the concentration of sorbic acid, dehydroacetic acid, benzoic acid, BHA, and p-hydroxybenzoates in imported fruit vinegar were 209, 281, 422, 3 and 2227 ppb, respectively.

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A method for the highly sensitive analysis of flavor components in several foods was developed using GC/MS equipped with a headspace sampler. A sample of food, beverage or fruit juice in a 20 ml vial was put in the headspace sampler, which was set to heat at 80°C for 20 min. Headspace gas (3 ml) was injected into the GC/MS by high pressure injection. This method of analysis was superior to the usual one, achieving about 3 to 10 times higher analytical sensitivity. The detection limits of flavor components by the proposed method were estimated to be at ppb level by total ion monitoring and ppt level by selected ion monitoring, respectively. This simple and easy method enabled routine flavor component analysis of several types of foods.

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A method for the automatic analysis of 8 chlorinated phennoxy acid herbicides was developed using an automated sample preparation instrument in combination with a GC/MS with negative ion chemical ionization (NCI). The instrument can automate many sample preparation steps, such as solid phase extraction (SPE) and derivatization. All of the following steps were automated. 1) A sample of 10 ml was injected into the SPE cartridge (THC) where 8 herbicides were retained. 2) The cartridge was then washed with dichloromethane. 3) The 8 herbicides were then eluated from the washed cartridge using 0.1% sulfuric acid-methanol (1 ml). 4) The eluate was evaporated to dryness. 5) A derivatizing reagent, 2% pentafluorobenzyl bromide (PFBBr) in toluene and triethylamine, was added to the eluate. 6) And finally, the reaction mixture-sample solution was injected into the GC/MS by high pressure pulsed splitless injection. The total analysis time for 4 samples was approximately 4 hrs. The detection limits of the 8 herbicides ranged from 10 ppt to 50 ppt. The overall recoveries of the herbicides except for picloram were from 82 to 102% {RSD (n=5) were from 4.1 to 9.1%} for river water and from 96 to 116% {RSD (n=5) were from 4.3 to 7.3%} for wine, respectively. The recovery of picloram was about 50%, but we could get good results by using a standard calibration curve.

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It is known that various kinds of organic compounds exist in space. In order to study the possibility of the formation of organic compounds in comets or their precursory bodies (intersteller dust grains), ice mixtures of carbon monoxide (or methane), ammonia and water made in a cryostat at 10 K ("simulated cometary ices") were irradiated with high energy protons. Irradiated ice products were warmed up to room temperature, while sublimed gases were analyzed with a quadrupole mass spectrometer. Some hydrocarbons and alcohols were detected. "Amino acid precursors" (compounds yielding amino acids after hydrolysis) were detected in non-volatile products remaining on the substrate at room temperature. These results suggest the possible formation of organic compounds in interstellar dust grains by cosmic radiation.

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In order to monitor ultra-trace amount of organotin compounds in seawater, a high sensitivity speciation method has been investigated using ICP-MS. Organotin compounds are volatilized from seawater by hydride generation, trapped on chromatographic packing material [Chromosorb GAW DMCS (SP-2100 3%, 6080 mesh)], then separated on the basis of different boiling points, and introduced into the ICP-MS. The species under investigation are triphenyltin (TPT), diphenyltin (DPT), monophenyltin (MPT), tributyltin (TBT), dibutyltin (DPT), monobutyltin (MBT) and inorganic tin. The ICP-MS is so highly sensitive that a little loss and/or contamination can produce large errors in speciation. The technical improvements are as follows: 1) a nebulizer was directly connected to a torch; 2) the top point of the nebulizer was cut; 3) the length of a teflon tube was shortened from 70 cm to 30 cm; 4) its inner diameter was changed from φ 1 mm to φ 5 mm; 5) the teflon tube was heated at ca. 120°C; 6) the quartz glass tube column for a trap was treated with dimethyl chlorosilan, 7) a water trap was removed; 8) sodium tetrahydroborate was refined by electrolysis. Consequently a satisfactory chromatogram of seven tin species can obtained. The limits of detection (3σ, ng 1^-1) are Sn (IV) 0.02, MBT 0.03, MPT 0.04, DBT 0.33, TBT 0.87, DPT 1.33, TPT 10.78.

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A micro method of high-performance liquid chromatography/fast atom bombardment mass spectrometry (LC/FAB-MS), which involves a micro silica gel column and a micro LC apparatus working at a flow rate of 6 ml/min, has been developed for the structural characterization of disialogangliosides of mouse thymocytes. Four disialogangliosides extracted from 2.2×10⁹ thymocytes were identified as [GDlc(NeuAc, NeuAc), GDlc(NeuAc, NeuGc), GDlc(NeuGc, NeuAc) and GDlc(NeuGc, NeuGc)] from the obtained mass spectra. This micro LC/FAB-MS system is useful not only for the structural characterization of neutral glycosphingolipid and monosialoganglioside mixtures, as reported previously, but also disialoganglioside mixtures prepared from a limited number of isolated cells.

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Characterization of reaction intermediates formed during organic reactions is essential to understand the mechanisms of chemical reactions. We developed two methods to analyze and determine chemical structures of reaction intermediates using mass spectrometry. The one is "a FRIT-FAB LC/MS method" which consists of a fast atom bombardment mass spectrometer (FAB-MS: JEOL Model DX-303) connected to an HPLC via a pneumatic splitting interface. To perform LC/MS analysis, HPLC effluent was introduced into the mass spectrometer after mixing triethylene glycol as a matrix modifier. The FAB-MS was operated by applying an accelerating voltage of 3 kV. The emission current and the voltage of the FAB gun was controlled to 10 mA and 4 kV, respectively. This method enables the detection of reaction having intermediates with more than 1 minute of life time. The other is "a Flow direct injection FAB-MS method (FDI/FAB-MS)". After mixing the solutions with two pistons continuously, the mixed solution is introduced into the FRIT-FAB mass spectrometer. The reaction time is controlled by changing the path-length of the sampling loops and the velocity of the flow rate. This is a suitable method by which to detect and estimate chemical structures of relatively short life time intermediates (more than a few seconds). Using these methods, we observed the oxidation reaction of hydrazine with quinone and clarifing the reaction scheme and confirming the validity of these methods.

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The electron impact (EI) mass spectra of three organosilicon compounds with two silicon atoms (CH₃)₂SiH-(CH₂)_n-SiH(CH₃)₂ (n=02) were measured and the fragmentation mechanisms were investigated by the deuterium-labelled technique and the B/E linked-scanning technique. In the EI mass spectrum of 1, 1, 2, 2-tetramethyldisilanes, the main fragmentation produced m/z 73 ions via a four-center transition structure. In bis-(dimethylsilyl)methane, methyl radical loss from molecular ion M⁺ was the main process, and most of the fragment ions were produced by the secondary decomposition of [M-CH₃]⁺. In 1, 2-bis(dimethylsilyl)ethane, Si-C bond cleavage occurred simultaneously with the Si-Si bond formation producing m/z 103 ions. In this process, a four-center transition state was involved. The optimized geometries of the neutral molecule and the molecular cation of bis(dimethylsilyl)methane were calculated using the ab initio MO method.

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The molecular weights of hapten-BSA conjugates were rapidly determined by MALDI-TOFMS. Forskolin, deacetylforskolin and etoposide were the haptens used to prepare the hapten-BSA cojugates. Protonated molecules ([M-E-H]⁺) of these cojugates were detected clearly by MALDI-TOFMS, and therefore, the number of haptens molecules bonded to BSA could be calculated easily. The relationship between the number or hapten molecules bonded to BSA and the immune response was studied. Enzyme-antibody conjugates were also determined by MALDI-TOFMS. In the HRPO-SOD antibody (IgG) conjugate, the ion of m/z 240000 was detected; this ion corresponds to the conjugate of three moles of HRPO bonded to IgG. There was a linear relationship between the number of HRPO molecules conjugated to IgG and ELISA activity.

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Reactions between poly(oxymethylene)glycols (POMGs) in aqueous solution and methanol or ethanol, which were closely related to the reactions occurring in an aqueous solution of formaldehyde, were studied by liquid ionization mass spectrometry. Hemiformalization of POMGs proceeded soon after the methanol addition to form monomethylethers of POMGs and completed within 15 min. In contrast, hemiformalization by the ethanol addition proceeded slowly. About 30 min is needed to produce monomethylethers of POMGs. Most ions of POMGs observed in aqueous solution, as well as the abundant monomethylether of POMG ions obtained upon mixing with methanol, were hydrated. In contrast, only a few ions of monoethylethers of POMGs were hydrated. These results suggest that methanol is able to react directly with hydrated POMGs, while the water molecules in a hydrated POMG must replaced with ethanol molecules prior to the formation of the monoethylether derivatives.

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The relationship between the ion association equilibrium in solution phase and the ion intensity ratio in electrospray (ES) mass spectra was studied using tris(2, 2'-bipyridine)ruthenium complex as a model solution. The ion concentration in solution was estimated from calculated ion association constants. The ion ratio of [Ru(bpy)₃ClO₄⁺]/[Ru(bpy)₃²⁺] as a function of counteranion concentration and dependence of counteranions on the ion ratio were measured in acetonitrile, acetone and methanol solution. The ion behavior in electrosprayed charged droplets was different from that in bulk solution. It was found that the ion ratio in the ES mass spectra was affected by both solvent concentration and ion evaporation rate of different charge states from charged droplets. The effect of different counteranions on the ion ratio showed that the ion association in the charged droplets was not explainable in terms of electrostatic interaction between counteranion and solvent.

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A charge neutralization method in SIMS was successfully applied to the analysis of La, Fe and Cr in Al₂O₃ films formed on Fe-20Cr-5Al alloy. The method consists of the preevaporation of Al or Au on the surface of the specimen except for the masked region and simultaneous irradiation of electrons. The surface charge was compensated for by the electron irradiation. The pre-evaporated film served as the surface charge path. Elemental depth profiles of the oxide films on annealed and as-rolled Fe-20Cr-5Al alloys showed that Fe and Cr were enriched in the surface region, the Fe concentration in the former being lower than that in the latter. La and Al were also enriched in the surface region on annealed specimens before oxidation. These results suggest that the diffusion of O during high temperature oxidation is retarded by the surface oxide film on annealed specimens, and consequently resistance to high temperature oxidation was improved.

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Trace analysis of nitrogen in silicon wafers was performed using SIMS on ¹⁴N implanted samples. The detection limits for nitrogen were defined as the constant level measured in the tail of ⁴²(N+Si)^- depth profiles. The effects of primary ion current and raster scan size on the detection limits were studied. Next, considerable intensity was observed in the negative bias region of the ⁴²(N+Si)^- energy spectra. These were thought to correspond to ions created by post-ionization of sputtered neutral atoms by primary ion impact, or by delayed-ionization near the sample surface. The potential of using the gas-phase ionization of sputtered neutral atoms to improve the detection limits was then evaluated. In addition, there are mass interference ions ⁴²(C+Si)^- for ⁴²(N+Si)^-. It was found that ⁴²(N+Si)^- has a lower energy distribution compared to ⁴²(C+Si)^-. Under optimal analytical conditions using gas-phase ions and avoiding interference from ⁴²(C+Si)^- by the energy filtering technique, the detection limit of 4×10¹⁵ atoms/cm³ for nitrogen was achieved.

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