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Rndirk » Wed Jun 07, 2017 11:53 am
This is a very general question. In what type of environment do you work (pharmaceutical, food,...?).
It depends on the instrument and on the analysis. Just repeating the SST until it passes is, in my opinion, not a good practice. You have to define the criteria of the SST so that, when it doesn't pass, something is wrong and needs to be fixed/ajusted.
If just re-injecting makes it pass, then your criteria are too narrow or the instrument is too unstable. I would advice to not take your criteria too narrow, but of course stay within the limits of legislation (if any). Take a good look at your validation data to define these. Which analyte, for instance, is most sensitive to the state of the instrument?
Most of the time people here recognize the issue or contact someone who is more experienced with the instrument and/or the specific application. Actions depend on the symptoms of course. An example in the case of an unstable HPLC pressure: changing pre-column, longer conditioning, rinsing column with high organic,....