The set of replicate field samples should be exposed to the same dust environment, either in a laboratory dust chamber [8] or in the field [9].The quality control samples must be taken with the same equipment, procedures, and personnel used in the routine field samples. Calculate precision from these replicates and record relative standard deviation (S r) on control charts. Take corrective action when the precision is out of control [8]
set of replicate field samples
replicate field