is a separate aliquot of the sample spiked with known concentrations of the analytes
of interest. It is analyzed to determine, including the matrix interferences, if the procedure is working
within established control limits. Like the Blank Spike it is carried through the complete preparation and
analytical procedure. It is routinely performed in duplicate as the MSD. The recoveries of the spiked
analytes are evaluated to determine accuracy in a given matrix. Comparison of the MS to the MSD will
yield a precision measurement in a given matrix.