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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Electron ionization | 4/4 | https://en.wikipedia.org/wiki/Electron_ionization | reference | science, encyclopedia | 2026-05-05T10:04:25.973339+00:00 | kb-cron |
=== Fourier transform ion cyclotron resonance mass spectrometry === FT- ICR EI - MS can be used for analysis of three vacuum gas oil (VGO) distillation fractions in 295-319 °C, 319-456 °C and 456-543 °C. In this method, EI at 10 eV allows soft ionization of aromatic compounds in the vacuum gas oil range. The compositional variations at the molecular level were determined from the elemental composition assignment. Ultra-high resolving power, small sample size, high reproducibility and mass accuracy (<0.4ppm) are the special features in this method. The major product was aromatic hydrocarbons in all three samples. In addition, many sulfur-, nitrogen-, and oxygen-containing compounds were directly observed when the concentration of this heteroatomic species increased with the boiling point. Using data analysis it gave the information about compound types (rings plus double bonds), their carbon number distributions for hydrocarbon and heteroatomic compounds in the distillation fractions, increasing average molecular weight (or carbon number distribution) and aromaticity with increasing boiling temperature of the petroleum fractions.
=== Ion trap mass spectrometry === Ion trap EI MS can be incorporated for the identification and quantitation of nonylphenol polyethoxylate (NPEO) residues and their degradation products such as nonylphenol polyethoxy carboxylates and carboxyalkylphenol ethoxy carboxylates, in the samples of river water and sewage effluent. Form this research, they have found out that the ion trap GC- MS is a reliable and convenient analytical approach with variety of ionization methods including EI, for the determination of target compounds in environmental samples.
== Advantages and disadvantages == There are several advantages and also disadvantages by using EI as the ionization method in mass spectrometry. These are listed below.
== See also == Ion source Penning ionization Chemical ionization Spark ionization Thermal ionization
== References ==
== Notes ==
== External links == NIST Chemistry WebBook Mass Spectrometry. Michigan State University.