SPSFAM Heavy Metals ERP Book

avg

where s = SD of replicates (micrograms per kilogram) and C avg = average concentration of replicates (micrograms per kilogram). (5) FAP .—For each batch and at least once for each separate matrix type, one FAPmust be prepared and analyzed to verify peak identification and quantitative recovery. It is recommended that the same sample be used for FAP recovery and precision. Fortifications (spikes) must be performed by adding standards to the juice matrix prior to dilution with DIW. If the recoveries are not acceptable, ensure that the spiking level is appropriate and reprepare and reanalyze the FAP sample. Reanalysis of the entire sample batch may be required. For peak identification, the chromatograms for the unfortified and fortified samples must be compared. An appropriate increase in peak area must be observed. In addition, the peak shape in the fortified sample chromatograms should be similar to that of the unfortified sample with no significant additional band

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