
Dushyant Patel LC-MS/MS Method
S.K.P.C.P.E.R., Kherva 25 M .Pharm. Thesis
Figure 4.3 APCI process in the positive ion polarity mode
Scan modes:
¾ The mass spectrometer can be operated in a variety of scan modes. The most commonly
used scan modes can be divided into two categories: single mass spectrometer scan
modes and MS/MS scan modes. The scan modes in each category are as follows:
• Mass spectrometer scan modes: Q1MS and Q3MS
• MS/MS scan modes: Product, Parent, Neutral Loss
• Data dependent scan mode
¾ The scan modes that can be employed depend on the number and type of rod assemblies
and the voltages applied to the rod assemblies. The mass analyzer has three rod
assemblies. The first and third rod assemblies, Q1 and Q3, are Hyper Quads (hyperbolic-
profile quadrupoles), and the second rod assembly, Q2, is a square-profile quadrupole.
¾ Rod assemblies can be operated in either of two capacities:
• Ion transmission devices
• Mass analyzers
¾ If only RF voltage is applied, a rod assembly serves as an ion transmission device that
passes all ions within a large range of mass-to-charge ratios (i.e., virtually all ions
present).
¾ When both RF and DC voltages are applied to a rod assembly, the separation of ions of
different mass-to-charge ratios occurs. This separation allows the rod assembly to serve
as a mass analyzer.
Komentáře k této Příručce