Chapter 20 - Chapter 20 Molecular Mass Spectrometry Mass...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 20 Molecular Mass Spectrometry Mass spectrometry is capable of providing information about (1) the elemental composition of samples of matter. (2) the structures of inorganic, organic, and biological molecules. (3) the qualitative and quantitative composition of complex mixtures. (4) the structure and composition of solid surfaces. (5) isotopic ratios of atoms in samples. MOLECULAR MASS SPECTRA Ethyl benzene, molecular mass of 106 dalton. The analyte vapor was bombarded with a stream of electrons that led to the loss of an electron by the analyte and formation of the molecular ion M + C 6 H 5 CH 2 CH 3 + e- C 6 H 5 CH 2 CH .+ 3 + 2e- The charged species C 6 H 5 CH 2 CH .+ 3 is the molecular ion . Relaxation occurs by fragmentation of part of the molecular ions to produce ions of lower masses. The positive ions produced on electron impact are attracted through the slit of a mass spectrometer where they are sorted according to their mass-to-charge ratios and displayed in the form of a mass spectrum. The largest peak, termed the base peak . ION SOURCES The starting point for a mass spectrometric analysis is the formation of gaseous analyte ions. Ion sources fall into two major categories: gas-phase sources and desorption sources . In the former, the sample is first vaporized and then ionized. In the latter, the sample in a solid or liquid state is converted directly into gaseous ions. ION SOURCES...
View Full Document

Page1 / 25

Chapter 20 - Chapter 20 Molecular Mass Spectrometry Mass...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online