Precision and determination of blanks

The reagent and system blanks must be recorded at specified intervals. These intervals may be related to the number of samples processed or may be fixed periods of time. Changes in the analytical system, including replacement of parts of the detector and new sets of reagents, should always be followed by blank controls. The blank values should be monitored using control charts. 

Detection limits (3 s of the blank values) of 0.05 ng/L have been reported for Hgx Bloom et al., 1995). With concentrations S 0.5 ng/L, relative standard deviations of between 5 and 

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