What are Matrix Spike and Matrix Spike Duplicates?
A Matrix Spike and Spike Duplicate (MS/MSD) are representative but randomly chosen client samples that have known concentrations of analytes of interest added to the samples prior to sample preparation and analysis. They are processed along with the same un-spiked sample. The purpose of the MS/MSD is to document the accuracy and precision of the method for that specific sample. Control charts are maintained that are indicative of typical MS/MSD recoveries of ‘real’ samples rather than laboratory controlled samples.
The importance of the MS/MSD is specific in nature. The MS/MSD is only significant to the client whose sample was chosen for spiking. The MS/MSD data serves as an indication of the problems that may be associated with a specific sample or sample site. For example, if a known concentration of Lead is added to a sample but only 20% is recovered, it may be an indication of matrix interference resulting in suppressed recovery of Lead. This is important when evaluating all of the lead results that may be associated with a group of samples taken from the same general location. The MS/MSD is not useful to a client whose sample was not chosen and thus, is not reported to that client unless specifically requested.