Extracting Mass Traces Online

Using Mass Spectrometers
Extracting Mass Traces Online

It is possible to extract Mass Traces (MS chromatograms) and save them as additional channels. This can be done either during data acquisition (online) or later (see Extracting Mass Traces Afterward).

In the Server Configuration Program, define the required number of Online Mass Extract Channels on the Installed Channels tab page. (Up to 32 channels can be defined.) These channels are automatically named MS_01 to MS_32.

Create a PGM File for data acquisition in Full Scan mode, using the Program Wizard (see The Control Program The Program Wizard). Each single MS channel needs its own AcqOn/Off command. Define the following parameters for each single MS channel:

Parameter	Min.	Max.	Default	Usage
FilterIndex	0: NoFilter	n: TICF_0n (MSQ) or TICF_n (aQa) (n = number of the TICF channel configured in the Server Configuration)	0	Selects the filter for extraction. The filter indexes correspond to the nine MSQ filters or the four aQa filters that can be defined in the MS method. 0 = NoFilter means that the TIC channel is used.
MinMass	0.00 m/z (MSQ) 2.0 m/z (aQa)	2000.00 m/z (MSQ) 1636.0 m/z (aQa)		Minimum mass of interval that will be extracted.
MaxMass	0.00 m/z (MSQ) 2.0 m/z (aQa)	2000.00 m/z (MSQ) 1636.0 m/z (aQa)		Maximum mass of interval that will be extracted.

These parameters cannot be set using the Program Wizard. Therefore, follow the steps below:

Open the PGM File.
Select Command on the Control menu to open the Commands dialog box.
Select your Mass Spectrometer (listed by the name defined in the Server Configuration).
Open the mass channel to be extracted; for example, MS_01.
Specify the individual parameters:

Use the Upper/Lower Limit parameters to specify the signal limits.

You can also extract the trace of the Base Peak. In this case, verify that the BasePeakMode property is set to Yes.

Tip:

Do not change the mass trace settings during a run. This might result in confusion. Therefore, Dionex recommends not entering a retention time.

The corresponding section in the Program could look as follows:

MS_01.MinMass = 149.5

MS_01.MaxMass = 150.5

MS_01.FilterIndex = 1

Tip:

To start data acquisition, manually enter the following command for the MS_01 channel:

MS_01.AcqOn

To stop data acquisition for the MS_01 channel, enter:

MS_01.AcqOff

You can display these channels on the Control Panel during data acquisition.