CHM151Y1 Lecture Notes - Lecture 86: Benzene, Alkene, Alkyne
Document Summary
A mass spectrometer is used to analyze ions in order to ind the molecular weight and chemical structure of a compound. A mass spectrum will usually be presented as a verical bar graph, in which each bar represents an ion having a speciic mass-to-charge raio (m/z) and the length of the bar indicates the relaive abundance of the ion. The most intense ion is assigned an abundance of 100, and it is referred to as the base peak. Most of the ions formed in a mass spectrometer have a single charge, so the m/z value is equivalent to mass itself. Modern mass spectrometers easily disinguish ions difering by only a single atomic mass unit and therefore, the masses are very accurate. Lower mass ion is the fragment, and the higher is the molecular ion. Steps in interpreing mass spectra data: look for the molecular ion peak, try to calculate the molecular formula.
