Axis BTA 2100D Manual del operador descargar pdf (Pagina 223)

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Automated Methods Development

Automated Method Development (AMD) is used to optimize CID conditions for

product ion formation in a MS/MS method. AMD uses up to 10 different sets of

conditions for the same parent ion.

 When using Automated Method Development (AMD) option, set the Saturn

method for 1 microscan per analytical scan by adjusting the Scan Time

(Segments Setpoints). The easiest way to do this is to use the down-scroll

button in the Scan Time edit control to reduce the time to its lower limit. The

software calculates the minimum scan time allowed based on the duration of

one microscan for the current method parameters. This will ensure that the

maximum number of cycles through the different voltages (scan segments)

across each peak is performed.

 A strategy for using AMD to determine the optimum excitation storage level

and excitation voltage:

1. Determine the parent ion and retention time for each compound from an

injection using normal EI mode. Build a multi-segment acquisition

method, with one segment per compound.

2. Use the default conditions with Automatic Methods Development to

determine the mass of the product ion(s). AMD allows the CID voltage to

be incremented on a scan-by-scan basis (25v, 30v, 35v) for up to 10

scans and then the cycle repeats.

3. Once the m/z value of the product ion is determined, make the following

calculation. Product ion m/z divided by 1.4 = the highest CID rf excitation

level. For example, if the product ion is m/z 140, then the rf excitation

level must be no higher than 100. This will ensure good trapping

efficiency of the product ion. The value of 1.4 is a ratio of the “q” ejection

value (.908) and the “q” value at Beta(1/3) of 0.63.

4. Once the rf excitation level is set, the only variable to optimize is the CID

voltage. This can be done with two injections using AMD. The first

injection can use voltage increments of 10 volts (Nonresonant) or 0.2

volts (Resonant). Once you get close with this first injection, lower the

voltage increment and optimize the voltage with the second injection.

Determining the Optimum Voltage for Nonresonant

Excitation Using Automated Methods Development

(AMD)

Follow these steps to determine the optimum voltage for nonresonant excitation

by using AMD while injecting the parent compound.

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