What does electron impact mass spectrometry detect?
In electron impact mass spectrometry, the collision of a high energy electron with a sample molecule produces a radical cation, M+·. We can identify the mass of the neutral particle that forms in a fragmentation reaction by subtracting the mass of the base peak from the mass of the parent ion.
What is the base peak in an electron impact mass spectrum?
Base peak: The most intense (tallest) peak in a mass spectrum, due to the ion with the greatest relative abundance (relative intensity; height of peak along the spectrum’s y-axis). Not to be confused with molecular ion: base peaks are not always molecular ions, and molecular ions are not always base peaks.
What is electron impact used for?
Electron Ionisation (often incorrectly called Electron Impact) is generally considered to be the ‘classical’ method of analyte ionisation. It is still routinely used today for the analysis of low-mass, volatile, thermally stable organic compounds which are difficult to ionise by other techniques.
What is the base peak in a mass spectrum?
Base peak: The most intense (tallest) peak in a mass spectrum, due to the ion with the greatest relative abundance (relative intensity; height of peak along the spectrum’s y-axis).
How does a mass spectrum work?
A mass spectrometer can measure the mass of a molecule only after it converts the molecule to a gas-phase ion. To do so, it imparts an electrical charge to molecules and converts the resultant flux of electrically charged ions into a proportional electrical current that a data system then reads.
Why are mass spectrometers important?
Typically, mass spectrometers can be used to identify unknown compounds via molecular weight determination, to quantify known compounds, and to determine structure and chemical properties of molecules.
What does the base peak tell you?
The vertical axis denotes the relative abundance of ions. The most intensive peak in a spectrum is called the “Base Peak”, whose intensity is taken as 100 percent. This ion exists most abundantly in the ion source and represents the most stable ion, which is useful for identifying the compound.