1 Va. Admin. Code § 30-45-760 - Quality control requirements
A.
General.
1. The quality control protocols
specified by the laboratory's SOPs shall be followed (1VAC30-45-730 C). The laboratory
shall ensure that either the (i) applicable essential standards outlined in
this section through
1VAC30-45-775,
1VAC30-45-790 through
1VAC30-45-798, and
1VAC30-45-810 through
1VAC30-45-818 or(ii) mandated
methods or regulations, whichever are more stringent, are incorporated into
their method SOPs. When it is not apparent which is more stringent, the quality
controls in the mandated method or regulations are to be followed.
2. All quality control measures shall be
assessed and evaluated on an ongoing basis and quality control acceptance
criteria shall be used to determine the validity of the data. The laboratory
shall have procedures for the development of acceptance/rejection criteria
where no method or regulatory criteria exists.
B. Initial test method evaluation. For all
test methods other than microbiology, the requirements of subdivisions 1 and 2
of this subsection apply. For microbiology testing, the initial test method
evaluation requirements are contained in
1VAC30-45-790 through
1VAC30-45-798. For the evaluation
of precision and bias (subdivision 3 of this subsection), the requirements of
subdivision 3 a of this subsection apply to standard methods. The requirements
of subdivision 3 b of this subsection apply to the methods referenced in that
subdivision.
1. Limit of detection (LOD).
a. The laboratory shall determine the LOD for
the method for each target analyte of concern in the quality system matrices
when the testing is conducted using approved methods listed in 40 CFR Part 136
for a program under the federal Clean Water Act, except when the procedure for
Determination of Method Detection Limit at 40 CFR Part 136 Appendix B states
the procedure is not applicable to a measurement.
b. The laboratory shall determine the LOD for
the method for each target analyte of concern in the quality system matrices
when test results are to be reported to the LOD (versus the limit of
quantitation or working range of instrument calibration), according to
1VAC30-45-771 and
1VAC30-45-814. Where an LOD study
is not performed, the laboratory may not report a value below the limit of
quantitation.
c. When the LOD is
required under subdivision 1 a or 1 b of this subsection, all sample processing
steps of the analytical method shall be included in the determination of the
LOD.
d. The validity of the LOD
shall be confirmed as described in 40 CFR Part 136 Appendix B as applicable, or
by qualitative identification of the analyte or analytes in a quality control
sample in each quality system matrix containing the analyte at no more than two
to three times the LOD for single analyte tests and one to four times the LOD
for multiple analyte tests. This verification shall be performed on every
instrument that is to be used for analysis of samples and reporting of
data.
2. Limit of
quantitation (LOQ).
a. The laboratory shall
determine the LOQ for each analyte of concern according to a defined,
documented procedure.
b. The LOQ
study is not required for any component or property for which spiking solutions
or quality control samples are not commercially available or otherwise
inappropriate (e.g., pH).
c. The
validity of the LOQ shall be confirmed by successful analysis of a QC sample
containing the analytes of concern in each quality system matrix at a
concentration at or below the LOQ or no more than two times the concentration
of the claimed LOQ. A successful analysis is one where the recovery of each
analyte is within the established test method acceptance criteria or client
data quality objectives for accuracy. This single analysis is not required if
the bias and precision of the measurement system is evaluated at the
LOQ.
3. Evaluation of
precision and bias.
a. Standard methods. The
laboratory shall evaluate the precision and bias of a standard method for each
analyte of concern for each quality system matrix according to either of the
following:
(1) The single-concentration
four-replicate recovery study procedures in
1VAC30-45-730 F; or
(2) An alternate procedure documented in the
quality manual when the analyte cannot be spiked into the sample matrix and
quality control samples are not commercially available.
b. Nonstandard methods.
(1) For laboratory-developed test methods or
nonstandard test methods that were not in use by the laboratory before July
2003, the laboratory shall have a documented procedure to evaluate precision
and bias. The laboratory shall also compare results of the precision and bias
measurements with criteria given in the reference method or criteria
established by the laboratory.
(2)
Precision and bias measurements shall evaluate the method across the analytical
calibration range of the method. The laboratory shall also evaluate precision
and bias in the relevant quality system matrices and shall process the samples
through the entire measurement system for each analyte of interest.
(3) The following are examples of a
systematic approach to evaluate precision and bias:
(a) Example 1. Analyze QC samples in
triplicate containing the analytes of concern at or near the limit of
quantitation, at the upper-range of the calibration (upper 20%) and at a
mid-range concentration. Process these samples on different days as three sets
of samples through the entire measurement system for each analyte of interest.
Each day one QC sample at each concentration is analyzed. A separate method
blank shall be subjected to the analytical method along with the QC samples on
each of the three days. (Note that the three samples at the LOQ concentration
can demonstrate sensitivity as well.) For each analyte, calculate the mean
recovery for each day, for each level over days, and for all nine samples.
Calculate the relative standard deviation for each of the separate means
obtained. Compare the standard deviations for the different days and the
standard deviations for the different concentrations. If the different standard
deviations are all statistically insignificant (e.g., F-test), then compare the
overall mean and standard deviation with the established criteria from
above.
(b) Example 2. A validation
protocol such as the Tier I, Tier II, and Tier III requirements in U.S. EPA
Office of Water's Alternate Test Procedure (ATP) approval process.
4.
Evaluation of selectivity. The laboratory shall evaluate selectivity by
following the checks established within the method. These checks may include
mass spectral tuning, second column confirmation, ICP inter-element
interference checks, chromatography retention time windows, sample blanks,
spectrochemical absorption or fluorescence profiles, co-precipitation
evaluations, and electrode response factors.
Notes
Statutory Authority: § 2.2-1105 of the Code of Virginia.
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