We are using Analyst in conjunction with our LC/MS/MS systems and are having an issue.

We have methods designed to quantitate multiple (like) analytes in a single run. However, occasionally we run into issues with linearity at the top of a calibration curve and must drop one of the calibration points (i.e. remove level 7 from a 7 point curve). This may only affect a single analyte, while the other curves are fine.

The problem we are having is that if you just drop a point by unselecting the 'Use Record' column, it still INCLUDES the ion ratios from that level when determining the ion ratio ranges. In order to exclude them in the calibration you must change the sample from 'Calibrator' to 'Unknown' type. This also removes the 'good' level 7 points from the other analytes.

Is there a way to exclude a calibrator (including in the ion ratio calculation) completely while leaving the other analytes unaffected?