1 In LCMS what is the best ionization method to use with the

1. In LC/MS, what is the best ionization method to use with the mass spectrometer, and why?

2. Why does a mass spectrometer need an ionization source?

Solution

1. the choice of ionization depends upon the nature of the sample and the type of information we require from the sample. if we need mass spectra with little or no fragment ions we can use soft-ionization methods.
a) Gas phase ionization- it relies on ionizing gas phase samples.
b) chemical ionization - this uses ion molecule reactions to produce ions from analyte.
Fast atom bombardment is one of the simplest technque of ionization. this can be used for a large variety od compounds and is goof for high-resolution measurements. we can give samples upto 6000Da.

2.in a mass spectrometer the electric and magnetic field exerts forces on charged particles in vaccum. therefore a compound must be charged or ionized to be analysed by a mass spectrometer.