For each batch of samples processed

For each batch of samples processed, at least one LCS must be carried throughout theentire sample preparation and analytical process as described in Chapter One. The laboratorycontrol samples should be spiked with each analyte of interest at the project-specific action levelor, when lacking project-specific action levels, at approximately mid-point of the linear dynamicrange. Acceptance criteria should either be defined in the project-specifc planning documentsor set at a laboratory derived limit developed through the use of historical analyses. In theabsence of project-specific or historical data generated criteria, this limit should be set at ± 20%of the spiked value. Acceptance limits derived from historical data should be no wider that ±