Resolving duplicate transitions

When you create multiple analytes that share precursor and product transition m/z values, the match between analytes and channels can be ambiguous.

One example is analyzing transitions from isomeric analytes that elute at different times but share the same mass (are isobaric).

If the duplicate transitions are in the same channel (for example, isomers in one channel), the QUAN Review application processes the data correctly without ambiguity. However, if you have identical transitions in different channels (for example, isomers acquired in separate channels), you must associate each analyte with the correct channel in the QUAN Review application.

You are informed of this ambiguity by a warning triangle on the OVERVIEW dashboard.
Notes:
  • You also see the warning triangle when you examine the embedded method, and you can resolve duplicate transitions in a similar way from that page.
  • You also see the warning triangle for duplicate transitions in the same channel. However, you do not need to resolve these duplicates. You only need to resolve duplicates that belong to different channels.

To resolve ambiguity for duplicate transitions:

  1. On the OVERVIEW dashboard, click the warning triangle .
  2. In the Resolve duplicate transitions dialog box, examine duplicate transitions in the table. The table includes the following columns for each analyte:
    • Analyte Name
    • Precursor Mass (m/z)
    • Product Mass (m/z)
    • Expected Retention Time (min)
    • Channel (see next step)
    Note: If you resolve duplicate transitions from the embedded method instead, this dialog box is titled Manage duplicate transitions.
  3. Use the Channel drop-down menu in each row to select the correct channel for each analyte. Each channel displays the following information:
    • Channel number
    • MRM transition m/z details
    • Cone voltage (V)
    • Collision energy voltage (V)
    • Ionization mode

    For example, 35: MRM 398.9 > 80.1 10V 35V ESI-, where the cone voltage is 10 V and the collision voltage is 35 V.

  4. When all analytes have the correct (unique) channel assigned, click Apply, and then click Close.
    The warning disappears and your results are reprocessed with the correct assignments.