Samsung RT34M Uživatelský manuál stáhnout pdf (Strana 38)

Dushyant Patel LC-MS/MS Method

S.K.P.C.P.E.R., Kherva 26 M .Pharm. Thesis

¾ On the mass spectrometer, the hyper quad rod assemblies can be operated with RF and

DC voltages or with only RF voltage. That is, Q1 and Q3 can act either as mass

analyzers or ion transmission devices. The Q2 rod assembly always operates with only

RF voltage. Thus, Q2 is always an ion transmission device. For a summary of how the

rod assemblies function in several of the major scan modes,

Table 4.1 Different Scan Mode (MS & MS/MS)

aScan = full scan or transmission of selected ions

bPass all ions or fragments = pass ions or fragments within a wide range of mass-to-charge

ratios

cFragment ions = collisions with argon gas cause ions to fragment

dSet = set to pass ions of a single mass-to-charge ratio or a set of mass-to-charge ratios

Scan types:

¾ Mass spectrometer can be operated with a three scan types.

• Full scan

• Selected ion monitoring (SIM)

• Selected reaction monitoring (SRM)

Full scan:

¾ The full scan type provides a full mass spectrum of each analyte. With full scan, the

scanning mass analyzer is scanned from the first mass to the last mass, without

interruption, in a given scan time.

¾ Full scan experiments are used to determine or confirm the identity of unknown

compounds or the identity of each component in a mixture of unknown compounds.

¾ The full scan type gives you more information about an analyte than does SIM, but a full

scan does not yield the sensitivity that can be achieved by the other two scan types. With

full scan, you spend less time monitoring the signal for each ion than you do in SIM or

SRM. Thus, full scan provides greater information but lower sensitivity than the other

two scan types.

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Samsung RT34M Uživatelský manuál Strana 38