Each analytical batch contains quality control samples such as method blank, laboratory control sample/duplicate, sample duplicate and sample/duplicate which are analyzed according to standard operating procedures. The method blank is used to document contamination and samples are qualified if blanks exceed thresholds. Laboratory control samples assess accuracy and are evaluated using percent recovery and control charts. Sample duplicates evaluate precision using relative percent difference.

1. Quality Control
Protocol for
Preparation Batch
Processing
WASTE WATER ANALYSIS

2. SUMMARY
Each analytical batch contains quality control samples such as method
blank, laboratory control sample/duplicate, sample duplicate and
sample/duplicate which is according to the Quality Control Section of
analysis’ standard operating procedures.
For analysis wherein Standard Method for Water and Wastewater
was used as reference, quality control samples are based on the quality
control practices Table 2020 of SMEWW.

3. PREPARATION
OF BATCH
 A group of samples of like matrices processed
together as a group within the same shift using the
same reagents. Each batch must minimally contain a
method blank, a laboratory control sample, and a
laboratory control sample duplicate. A batch can be
defined as one of the following:
 A set of field samples, less than or equal to 20 in
number, from multiple work orders that are processed
together, or
 A set of field samples, less than or equal to 20 in
number, from one work order that are processed
together

4. METHOD
BLANK
 The method blank is an interference free matrix to
which all reagents are added in the same volumes or
proportions as used in sample processing. The
method blank must be carried through the complete
sample preparation and analytical procedure. The
method blank is used to document the
presence/absence of contamination resulting from
the analytical process.
 As a minimum include one reagent blank with each
sample set (batch) or on a 5% basis, whichever is more
frequent.

5. METHOD
BLANK
 EVALUATION OF BLANK
 If the reagent blank is less than the MDL and
sample results are greater than the MQL, then no
qualification is required.
 If the blank is greater than the MDL, but less
than the MQL and sample results are greater
than the MQL, then qualify the results to indicate
the analyte was detected in the reagent blank
 If the reagent blank is greater than the MQL,
further corrective action and qualification is
required.

6. LABORATORY
CONTROL
SAMPLE/
DUPLICATE
(LCS/LCSD)
 An interference free matrix spiked with a known
concentration of target analyte(s) prior to sample
preparation and analysis. The Laboratory Control
Sample is used to assess analytical accuracy
independent of matrix interference.
 At least10 times the MDL
 Midpoint calibration
 Analyzed every batch of analysis

7. LABORATORY CONTROL SAMPLE/DUPLICATE
(LCS/LCSD)
 EVALUATION OF LCS
 % Recovery evaluation
 Control Charts

8. LABORATORY-
FORTIFIED
MATRIX (LFM)
 An additional portion of a sample to which a known
amount of the analyte of interest is added before
sample preparation.
 Some analytes are not appropriate for LFM analysis.
 At least one LFM per batch

9. LABORATORY- FORTIFIED MATRIX (LFM)
 EVALUATION OF LFM
 % Recovery
 If LFM results are out of control, then take corrective action to rectify the matrix
effect, use another method, use the method of standard addition, or flag the data if
reported.

10. SAMPLE
DUPLICATE (DUP)
 A duplicate aliquot of field sample
processed as a separate sample. The
duplicate is used to assess precision of the
analytical process and monitor sample
homogeneity.
 Gravimetric- one duplicate every 10 samples
(LOW and HIGH)
 Spectrophotometric – one every batch
 Titrimetric – one every batch
 Electrometric and Others– one duplicate every
10 samples

11. SAMPLE DUPLICATE (DUP)
 EVALUATION OF DUPLICATE
 Relative Percent Difference

12. CALIBRATION CURVES
A. INSTRUMENT
CALIBRATION
• Perform instrument maintenance
and calibration according to method
or instrument manual instructions.
Conduct instrument performance
according to the test method.
01
B. INITIAL CALIBRATION
• Perform initial calibration using at
least three concentrations of
standards for linear curves. Set the
lowest concentration at the
reporting limit.
02
C. CALIBRATION
VERIFICATION
• Analysts periodically use a
calibration standard to confirm that
instrument performance has not
changed significantly since initial
calibration.
03

13. CALIBRATION CURVES
 EVALUATION OF CURVES
 Correlation Coefficient must be > 0.995
 % Difference calculated at least <10% Diff

14. CALIBRATION
VERIFICATION
INITIAL CALIBRATION VERIFICATION (ICV)
• Performed after initial calibration
• Mid point concentration of the curve
• From different source with the calibration curve
• % Recovery and %RPD calculated
INITIAL CALIBRATION BLANK (ICB)
• Performed after initial calibration
• Blank run with reagents
• Must be <MDL
CONTINUING CALIBRATION VERIFICATION (CCV)
• Performed after running 10 samples and before closing the analysis sequence
• Mid point concentration from the curve
• SAME source with the calibration curve
• % Recovery and %RPD calculated
CONTINUING CALIBRATION BLANK (CCB)
• Performed after running 10 samples and before closing the analysis sequence
• Blank run with reagents
• Must be <MDL