3.
An analyst intended to determine the trueness of the method. He analyzed a food sample by LC-MS. He carefully homogenized the sample in a blender and divided it into 10 subsamples and added a known amount of standard solution in each subsample. With the subsamples he carried out sample preparation (consisting of extraction, precipitation and centrifugation). As a result he obtained a clear solutions that he diluted to 1 mL with mobile phase. He analyzed all samples during the same day and divided the mean analyte amount detected by the analyte amount added to the sample.