Full scan analysis purposes

Fit the purpose calibration. It is common sense to check instrument performance each day, and GLP requirements simply formalize the performance and documentation of these checks. On the other hand, it is also important to use the right test (full calibration, verification, system suitability test, or instrument and method validation) to verify the performance and to avoid needlessly lengthy procedures. As already discussed (see Sections 13.2.3 and 13.3.1), it is not always necessary to perform a MS full calibration every day. For example, if a particular MS is used only to record complete full-scan mass spectra, a daily calibration or verification of the calibration of the m/z ratio scale is required. However, in the case where a MS is coupled with an LC and utilized primarily for the analysis of one or more analytes in the selected ion monitoring (SIM) mode, it does not always require a daily verification of the calibration. In this specific case it is quite common in LC-MS and LC-MS/MS applications to test only the following performance parameters (a) sensitivity, (b) system precision,... 

The major limitation of QqQ working in the MRM mode is that a complete mass spectrum cannot be obtained, so it is difficult to detect the presence of metabolites or nontarget compoimds. This concern is important when metabolites are explicitly included in the list of the regulated substances, (e.g., benzoimidazoles, carprofen, ceftiofur, and florfenicol) [11]. Conversely, the classical tridimensional ion trap analyzer has been used for this purpose [34], because it provides high sensitivity in full-scan mode and has the ability to perform multiple-stage fragmentations (MS" ), but it does not have adequate sensitivity and reliability to perform quantitative trace analysis. 

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