A second aliquot from a randomly chosen sample is fortified with a known concentration of target analytes. The sample is processed through the entire analytical method. Results are expressed as a percentage recovery.
Frequency and Purpose
Optional control measure. Ideally 1 per analytical batch run.
Evaluates any "matrix effects" that may exist in a sample due to its composition that may affect the recovery of analytes. An example is the presence of peat in soils, which tends to adsorb analytes such as benzene resulting in a poor matrix spike recovery.
Application and Regulatory Criteria.
Used for most analytical procedures. Matrix spike alert criteria apply when the target concentration is ≥ the native analyte concentration.
|CPs, PFOS, PAHs, 1,4-Dioxane, VOCs, THMs, BTEX||50% - 140%|
30% - 130% for difficult compounds
|PHCs, HWSB, Methyl Mercury||60% - 140%|
|Dioxins & Furans||50% - 150%|
|Metals and Inorganics, FOC||50% - 150%|
Bureau Veritas Laboratories recommends using the alert criteria listed here (adopted from the new CCME Analytical Protocol). Re-analysis of the Matrix Spike (MS) is performed if the Matrix Spike for a single analyte test or 10% of the analytes in a multi-element scan are outside the control limits by > 10% absolute. It should be noted that higher levels of uncertainty in the data are associated with situations when native analyte concentrations are > MS concentrations.