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Appendix A
5/20/2009
7
the procedure (Section xx) and report the concentration values
in the appropriate units. Calculate the MDL as follows:
MDL = S x 3
Where,
S = Standard Deviation of the
replicate analyses.
9.2.4
MDLs should be determined yearly.
9.3
Assessing Laboratory Performance
9.3.1
Laboratory Reagent Blank (LRB) – The laboratory must
analyze at least one LRB with each batch of samples. The
LRB consists of Nanopure water treated the same as the
samples. LRB data are used to assess contamination from the
laboratory environment.
9.3.2
Quality Control Sample (QCS)/ Standard Reference Material
(SRM) – when using this procedure, a quality control sample is
required to be analyzed at the beginning of the run and end of
the run, to verify data quality and acceptable instrument
performance. If the determined concentrations are not within
±
3
σ
of the certified values, performance of the determinative
step of the method is unacceptable. The source of the problem
must be identified and corrected before either proceeding with
the initial determination of MDLs or continuing with the
analyses. The results of these samples shall be used to
determine batch acceptance.
9.3.3
The QCS will be obtained from a source external to the
laboratory and different from the source of calibration
standards.
9.4
Data Assessment and Acceptance Criteria for Quality Control Measures
9.4.1
If a Total Volatile Solid (TVS) result is more than the Total
suspended Solid (TSS) result, an error code 9 is assigned to
the sample.
9.4.2
If duplicates have been provided for a sample, the results of
the two numbers must be compared to each other. If the
difference between the two numbers is equal to or more than
50% of the lower number then an error code 14 is assigned.
9.5
Corrective Actions for Out of Control Data
9.5.1
Out of control data is not reported. Generally portions of the
pad are missing and therefore the measurement is considered
useless. An error code is assigned.