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Operating Instructions — Acquisition Methods
Add a Period
•
In the Acquisition method pane, right-click the Mass Spec icon, and then click Add
period.
A period is added below the last period created.
Copy an Experiment into a Period
Prerequisite Procedures
• Open a multi-period method
•
In the Acquisition method pane, press CTRL, and then drag the experiment to the
period.
The experiment is copied below the last experiment in the period.
Copy an Experiment within a Period
Use this procedure to add the same or similar experiments to a period if most or all of the
parameters are the same.
•
Right-click the experiment and then click Copy this experiment.
Scan Techniques
MS: In MS scans, also referred to as single MS scans, ions are separated according to their
mass-to-charge (m/z) ratio. A single MS scan may be used to determine the molecular weight of
a compound. Single MS scans can also be referred to as survey scans. MS scans do not provide
any information as to the chemical make-up of the ions other than the m/z ratio. Perform MS/MS
or MS/MS/MS scan types to obtain more information about the ions.
MS/MS: MS/MS scans are used to help identify or confirm a molecular species. In MS/MS scans,
a precursor ion can be fragmented in one of two locations.
•
For triple quadrupole systems, fragmentation occurs in the collision cell.
•
For LIT systems, fragmentation can occur in the collision cell or the linear ion trap.
If enough energy is used, the precursor ion fragments to produce characteristic product ions.
MS/MS/MS: The LIT instrument MS/MS/MS scans go one step further than MS/MS scans. A
fragment that is produced in the collision cell is fragmented further in the trap to give more
structural information about the molecular ion.
Quadrupole-Mode Scan Types
Triple quadrupole instruments have high-sensitivity Multiple Reaction Monitoring (MRM)
capabilities required for quantitation experiments. In addition, they have highly specific scan
types, such as precursor ion and neutral loss scans, that allow a more advanced search to be
performed on the components of the samples.
Q1 MS (Q1): A full scan using the first quadrupole (Q1). The ion intensity is returned for every
mass in the scan range.
4500 Series of Instruments
54 of 138
System User Guide
RUO-IDV-05-0264-A
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