A simple mass spectrometer may include an electron ionization (EI) source and a magnetic sector mass analyzer. In this type of instrument, singly charged ions are produced and accelerated through the slit to the analyzer by applying high potentials to accelerator plates. If an ion with mass 293 amu and charge z = 1 is accelerated by a potential of 7500 V, what is its kinetic energy (in J)?
1. What is its kinetic energy (in J)?
Note: The following information may be useful for solving the two parts of this problem. 1 amu = 1.66 x 10^-27 kg. Electronic charge, e = 1.602 x 10^-19 C. 1 J = 1 kg m^2/s^2. 1 V = 1 J/C.
2. What is the velocity of the ion?
Part B
Match each statement with the term it most closely matches.
A. Electrospray Ionization (ESI)
B. Quadrupole
C. Magnetic sector
D. Hard ionization
E. Molecular ion peak
F. Fast atom bombardment (FAB)
G. Matrix-Assisted Laser Desorption/Ionization (MALDI)
H. Ion-Trap
I. Soft ionization
J. Time of Flight (TOF)
K. Base peak
........ Feature in a mass spectrum that is due to a singly charged ion that has the same mass as the analyte.
........ General term used to describe ionization techniques that produce few ion fragments. Chemical ionization is an example of this.
........ This ionization technique is used to analyze large, non-volatile molecules. The analyte is dissolved in a liquid matrix and placed on a target where it is impacted with an atom beam.
........ Mass analyzer in which ions are separated by their velocity. Ions sequentially strike the detector in order of increasing m/z.
........ This ionization technique is used to analyze large, non-volatile molecules. Ions are formed by placing the analyte in an excess of UV-absorbing molecules, followed by irradiation with a laser.
........ Analyzer that is based upon the deflection of ions in a magnetic field.
........ Analyzer that scans DC and RF amplitudes to generate a mass spectrum.
Part C
Consider the following statements as they apply to mass spectrometry. Decide if each is true or false.
....... Nominal mass, isotopic mass, and average mass are three terms that have the same meaning for mass spectroscopists.
....... A GC is commonly used as a mass spec inlet system because it can be used to separate mixtures of analytes before analysis.
........ A sample must be ionized in order to be separated in a mass analyzer.
........ In order to get a mass spectrum of an analyte, it must have a significant vapor pressure.
........ A mass spectrometer is an instrument that produces ions and separates them according to their mass-to-charge ratios, m/z.