In the SST/IRC page, the criteria that characterize expected results of an injection are referred to as test cases. You can specify as many test cases as you need to check whether a check standard injection was valid.
IMPORTANT
Make sure that all other parameters of the processing method are the same as those that you use in the processing method for sample injections, for example, the MS Detection parameters and the MS Chromatogram Settings. If you later modify the processing method used for the samples, do not forget to keep the SST processing method aligned with these changes.
For each test case, follow the New Test Case wizard. The wizard lets you specify expressions built from report variables, their statistics and operators that validate the values. For more information on SST test cases, refer to the Chromeleon CDS Software User Help.
Some examples of test cases that you might use are the following:
- To check the overall intensity of your MS signals, select Signal Statistics from the Chromatogram category of report variables, and check that the maximum of the whole chromatogram is above a certain expected value.
- To check mass accuracy, select Mass Accuracy from the Peak Purity and Identification > Composite Scoring category, and check that for a selected peptide it is below a certain limit. You can specify multiple test cases for several different peptides.
- Similarly, you can check whether retention times of selected peptides fall within a certain expected window and whether their peaks match the expected areas (or heights).
- To check the level of modification for a particular peptide, you can use report variables to calculate the sum of peak areas of the modified and unmodified peptide, and check whether the percentage of the modified peptide peak area in this sum is below a certain limit.