How are responses calculated in TargetLynx or QuanLynx when Use Trace in Response Calculation is enabled for more than one trace on the Target Ion Properties page in the TargetLynx method? -WKB111958

ENVIRONMENT

• MassLynx
• TargetLynx
• TargetLynx XS
• QuanLynx

ANSWER

QuanLynx and TargetLynx always use the Response.

The calibration is plotted as Response vs Conc., with the equation being:

Response = (Conc. * Slope of the curve) + Intercept of the curve

The calculation for concentration is then:

Conc. = (Response – Intercept of the curve) / Slope of the Curve

There are two calculations for Response, Absolute (no IS) and Relative (w/ IS).

The Absolute response is just that, the area or summed areas of the chromatographic peaks in question. (This also applies to Peak Heights.)

If the method is set to Use Trace in Response Calculation for all traces, (Quan and Secondary for QuanLynx, or Quan plus up to four Targets for TargetLynx), the Absolute Response will be the sum of the peak areas. This value is then used as the Response in the calibration and concentration equations.

The Relative response is calculated as follows:

Rel. Response = (Analyte Abs Area / IS Abs Area) * Conc. of IS

The value calculated here is then used in the calibration and concentration equations.

When "use Trace in Response..." is selected, TargetLynx will add together the peak area (or height) for all peaks associated with the compound. Abs Resp = A-qt + A-t1 + A-t2.... for QL Abs Resp = Aqt + A2nd

The areas are simply added together.

All of these calculations happen as described, regardless of which columns are displayed in the Summary Bar or the reports.

This all said, if you want to display the appropriate columns for response, they would be Peak Response (Response), Absolute Response (Analyte), and IS Abs Resp (IS). For the individual peaks that are being summed, the software will show them for the analyte peak, but there is no column to display the secondary ion peak area or target ion peak area for the IS when displaying the results for the analyte. This would be shownonly when displaying the results for the IS itself.

ADDITIONAL INFORMATION

In TargetLynx and TargetLynx XS, there is the Quantification Trace and up to four Target Ion Traces that can be included in the Response calculation. In QuanLynx, there is the Quantification Trace and the Secondary Ion Trace.