Keiichiro Iwase

Lithium ion attachment mass spectrometry for on-line analysis of trace components in air: direct introduction

Abstract Lithium ion attachment mass spectrometric method has been successfully applied for the real time, on-line continuous measurement of trace (ppb) organic compounds in air. The method is based upon the establishment of adducts with Li+ ions, which attach to most organic compounds in air but do not react with any of the major components of air. This paper describes the application of on-line, continuous analysis of volatile organic compounds in air using strawberries as a source of organic volatiles.

Li+ Ion Attachment Mass Spectrometry

PROBLEM TO BE SOLVED: To provide ion attachment mass spectrometry, capable of correctly discriminating and qualitatively/quantitatively analyze at least two kinds of identical mass, of different ingredient subject gases. SOLUTION: This ion attachment mass spectrometric method is for qualitative/quantitative analysis, and makes ion generated by the ion-releasing body 18 attach to a molecule of measurement gas, and the mass of the attachment ions is measured by the Q-pole mass analyzer 30. Further, the method comprises a step for making the difference of attachability of each of subject molecule, by making a specific molecule attach to molecules at least two kinds of identical mass but different ingredient subject gases of measuring object, and a step for measuring the identical mass while discriminating different components object gases. COPYRIGHT: (C)2008,JPO&INPIT

Mass spectrometric studies of ionic products in CF4/He and CF4/O2/He microwave discharge plasmas

Ionic species produced in CF4/He and CF4/O2/He microwave discharge plasmas were analysed by quadrupole mass spectrometry. Possible assignment was done, and the product species were classified into types. In the CF4/He plasma, F+, CF+, CF2+, and CF3+ were detected, and some new species were also found. The effect of adding O2 to the CF4/He plasma was also investigated. The total intensity of the ionic species decreased with increasing O2 volume. Mass peaks in the range from m/z100 to 200 were not observed at high O2/(O2 + CF4) ratios. CxFy+ species disappeared even at low O2 content, suggesting that polymerization was suppressed by oxygen. The intensities of F+ and CF2+were higher at the 3% O2/(O2 + CF4) ratio than when there was no O2 present, but their intensities decreased as the O2 content increased. In contrast, the CF3+ intensity decreased continuously as the O2 content increased.

Mass spectrometric analysis of ionic and neutral species produced in an N2/O2 microwave discharge plasma

A quadrupole mass spectrometer combined with a Li+ ion reactor setup was successfully used to qualitatively analyse and follow the evolution of the ionic and neutral species produced in an N2/O2 microwave discharge plasma. Mass spectrometric analysis showed that significant amounts of gas-phase neutral NO2 and HNO2 were produced in addition to the familiar NO and N2O species, detected in the form of Li+ adducts. A number of ionic clusters due to gas-phase ion-molecule reactions were detected.

Determination of the ionic and neutral chemical components of a H2O microwave discharge plasma

Abstract Li + ion attachment mass spectrometry was used to determine the ionic and neutral chemical components of a flowing microwave (MW) discharge plasma of H 2 O. The plasma composition was investigated as functions of H 2 O (in helium) flow rate (pressure) and MW-induced power input. Our study clearly showed the presence of various clustering compounds of water as well as their ionized species. Among compounds are the interesting ionic series H 3 O + (H 2 O) n O ( n =0–2) and (H 2 O) n + O ( n =0–4), which have not been reported before. We consider the reaction schemes for some products, particularly with regard to the role of radical and ionic condensation reaction processes. We attempted to link both the ionic and neutral species to a mechanism. Our predictions indicate that, for example, the principal ionic condensation reaction can be summarized by the reaction sequence H 3 O + (H 2 O) n X+H 2 O→H 3 O + (H 2 O) n +1 X (X=O, OH), while involving the OH radical may lead to the formation of (H 2 O) n Li + OH adduct species.

Mass spectrometric detection of H2O2H+: a CH4/O2 microwave discharge plasma

Abstract This Letter is concerned with the presence of H 2 O 2 H + in the gas phase. During the studies on the identification of the principal species produced by the CH 4 /O 2 microwave (MW) discharge, we have succeeded in determining the presence of the protonated hydrogen peroxides H 2 O 2 H + in the gas phase. The mass spectra of the discharge plasma, obtained by a direct sampling system, clearly show the peak m / z 35 (H 2 O 2 H + ), giving the direct evidence that H 2 O 2 H + is formed in the plasma environment and detected mass spectrometrically. The influence of certain discharge variables on yield and concentration of H 2 O 2 H + were investigated.