In any method, if a QC check such as a LFB fails, the first thing to do is re-run that QC check. Occasionally, an instrument will just have a hiccup (for example, an auto-sampler withdraws only a partial volume). Confirm by re-running the QC check. If it still fails, then prepare a new QC check and evaluate it. That lets you know if you might have prepared the initial QC check incorrectly. If it fails, then you will need to cast a wider net to uncover the problem and that may entail re-preparing the entire batch.
I need clarification on what is considered to be acceptable remedial action for a laboratory fortified blank QC sample that does not meet the acceptance criteria of the reference EPA Method.
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