Application of a trochoidal electron monochromator/mass spectrometer system to the study of environmental chemicals

Journal Article · Thu Oct 15 00:00:00 EDT 1992 · Analytical Chemistry (Washington); (United States)

DOI:https://doi.org/10.1021/ac00044a003· OSTI ID:7186792

Laramee, J A; Kocher, C A; Deinzer, M L ^[1]

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1. Oregon State Univ., Corvallis (United States)

A trochoidal electron monochromator has been interfaced to a mass spectrometer to perform electron capture negative ion mass spectrometric (ECNIMS) analyses of environmentally relevant chemicals. The kinetic energy of the electron beam can be varied from 0.025 to 30 eV under computer control. No reagent gas is used to moderate the electron energies. An electron energy spread of +/- 0.1 to +/- 0.4 eV full width at half-maximum (fwhm) can readily be obtained at a transmitted current of 2 x 10(-6) A, improving to +/- 0.07 eV at 5 x 10(-7) A. Comparisons of ECNI results from the electron monochromator/mass spectrometer system with those from a standard instrument that uses a moderating gas show similar spectra for heptachlor but not for the s-triazine herbicides, as for example, atrazine. This compound shows numerous adduct ions by standard ECNIMS that are eliminated by using the electron monochromator to generate the mass spectra. Isomeric tetrachlorodibenzo-p-dioxins show distinct differences in the electron energies needed to produce the maximum amount of parent and fragment anions. Multiple resonance states resulting in stable radical anions (M.-) are easily observed for nitrobenzene and for polycyclic aromatic hydrocarbons. Ionic products of dissociative electron capture invariably occur from several resonance states.

• OSTI ID: 7186792
• Journal Information: Analytical Chemistry (Washington); (United States), Vol. 64:20; ISSN 0003-2700
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ENVIRONMENTAL MATERIALS
CHEMICAL ANALYSIS
POLLUTION
ANIONS
CHEMICAL WASTES
ELECTRON CAPTURE
ELECTRONS
HERBICIDES
IONS
KINETIC ENERGY
MASS SPECTRA
NITROBENZENE
POLYCYCLIC AROMATIC HYDROCARBONS
RESONANCE
RESONANCE IONIZATION MASS SPECTROSCOPY
AROMATICS
CAPTURE
CHARGED PARTICLES
ELEMENTARY PARTICLES
ENERGY
FERMIONS
HYDROCARBONS
LEPTONS
MASS SPECTROSCOPY
MATERIALS
NITRO COMPOUNDS
NONRADIOACTIVE WASTES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PESTICIDES
SPECTRA
SPECTROSCOPY
WASTES
400201* - Chemical & Physicochemical Properties