§450.1120. Reference Materials

a)         Reference materials shall be used for each test procedure.

 

b)         Statistical methods, using at least 20 measurements, shall be used to calculate the mean value and standard deviation and set action limits for at least one reference material for each quantitative test.

 

c)         The results of the analysis of the reference material(s) for each day of testing shall be recorded and shall be clearly displayed. Action limits shall be clearly displayed and used to detect problems. Results and action limits shall be available for inspection.

 

d)         Each test procedure shall have a plan for remedial action to be taken in response to detected problems as soon as discovered.

 

e)         When lot numbers (batches) of reference materials are changed, the old and new lots shall be tested in parallel until suitable action limits are obtained for the new lot.

 

f)         All methods which do not have reference materials shall be controlled by duplicate testing with established tolerance limits.

 

(Source:  Amended at 13 Ill. Reg. 11573, effective July 1, 1989)