Detection methods/detectors differential response

The limit of detection (LOD) is that concentration which can be differentiated from a blank, while the limit of quantitation (LOQ) is the lowest concentration which can be determined with an acceptable accuracy and precision. It is important to realise that with most instruments, when a capillary is replaced, in most cases the detector flow cell is also replaced since detection takes place on-column. In this case, although the entire method need not be re-validated, the limits of detection and limits of quantitation, if these are appropriate to the method validation being undertaken, should be redetermined. Minor variations in capillary alignment can be sufficient to produce significant changes in detector response and sensitivity. This may not be necessary when using a decoupled detection cell. 

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