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MERC STDN Test Plan
13
calibrated in-house, the laboratory shall have a documented record of the calibration data
showing traceability to national standards. Since the capacity of volumetric glassware may
change with use, the calibration should be verified at regular intervals. Volumetric capacity is
normally determined gravimetrically, using water conforming to the MERC glassware
calibration Standard Operating Procedure (SOP). Before starting, care will be taken to ensure
that the glassware is clean.
Field Logs:
Standard uniform field logs will be maintained for the evaluation. These logs should
report name of staff conducting fieldwork, date (month, day, and year), operating status of all
equipment, and manual readings of environmental conditions.
Field Quality Control Samples:
Field quality control samples provide information on the potential for bias due to
contamination of analytical results by sample collection, processing, shipping, and analysis. To
ensure that the field sample collection and analysis procedures are properly controlled, field
blanks and replicate samples will be taken three times during the evaluation. These will be
analyzed in the same manner as the collected samples for Chlorophyll, TSS, and POC. Field
blanks are generated under actual field conditions and will account for all sources of
contamination that might be introduced to a sample including incidental or accidental sample
contamination during the entire process of sampling, transport, sample preparation, and
processing. While field blanks mimic sample collection and processing, they do not come in
contact with ambient water.
Sample Custody:
All samples will be accompanied by the sample collection sheet and a Chain-of-Custody
(COC) form.
The COC specifies time, date, sample location, unique sample number, requested
analyses, sampler name, required turnaround time, time and date of transaction between field and
laboratory staff, and name of receiving party at the laboratory. Proper labeling of sample bottles
is critical. The COC is a mechanism by which a sample can be tracked through the various
phases of the process: collection, shipping, receiving, logging, sample prep/extraction, analysis,
and final data QA/QC review.
When transferring the possession of the samples, the transferee must sign and record the
date and time on the chain-of-custody record. Custody transfers, if made to a sample custodian
in the field, should account for each individual sample, although samples may be transferred as a
group. Every person who takes custody must fill in the appropriate section of the chain-of-
custody record. The MERC staff member is responsible for properly packaging and dispatching
samples to the laboratory for analysis. This responsibility includes filling out, dating, and
signing the appropriate portion of the chain-of-custody record. The original and one copy of the
chain-of-custody record form should be placed in a plastic bag inside the secured shipping
container with the samples. One copy of the chain-of-custody record form should be retained by
the MERC staff member at each MERC partner institution. The transportation case should then
be sealed and labeled. All records should be filled out legibly in waterproof pen.