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Ref. No. [UMCES] CBL 2015-009
ACT VS15-02
12
documents (Dickson et al. 2007). Each reference sample was dated and coded according to site,
test condition and sample sequence. The actual sample container was labeled with a number for
identification. The reference sample number was used in all laboratory records and Chain-of-
Custody (COC) forms to identify the sample. The COC specified time, date, sample location,
unique sample number, requested analyses, sampler name, required completion time, date and
time of sample transaction, and name of receiving party for the samples. Proper labeling of
sample bottles was critical. The COC was a mechanism by which samples could be tracked
through the various phases of the process: collection, shipping, receiving, logging, sample
prep/extraction, analysis and final data QA/QC review. Transfer of reference samples from field
personnel to laboratory personnel was also recorded on the COC and records were maintained in
the laboratory with the names and signatures of persons leaving and receiving the custody. All
logs were duplicated weekly. The original log was retained at the ACT Partner site and a copy
was sent to the ACT Chief Scientist. Accumulated samples to be analyzed by outside
laboratories were shipped for analysis at the end of the month long deployment tests, and
monthly for the extended HI deployment. Samples stored on site were routinely inspected by
ACT personnel to assure proper preservation and label integrity. All reference samples not
immediately analyzed on site by ACT staff were accompanied by the sample collection sheet and
COC forms.
Analytical Methods for Reference Samples -
Three spectrometer cells (10 cm cylindrical
cell) were filled at the deployment site for each field reference sample, and transported directly
to the lab. All analysis was done at a fixed temperature for a given test site. The measurement
temperature was 25°C for HIMB, 20°C for MLML, 15°C for CBL and 25°C for Lake Michigan.
The temperatures for CBL and Lake Michigan were estimated to be near the mid-point of the
expected 30 day ambient range. Filled cells were incubated in a cell warmer (manufactured at
USF according to Bob Byrne’s specifications) to reach the specified analytical temperature
(typically between 30 min to 1 hour). The Agilent had a thermal jacket surrounding the
spectrophotometer cells that was continuously flushed with the same water bath that also
supplied the cell warmer. Past experience at Byrne’s lab has shown that this system can
maintain cells at a constant temperature within ± 0.1
o
C or better. After the initial dye reading,
the sample was re-blanked and then a second 10 µl aliquot of dye was added and the R-ratio re-
measured to enable a correction for the effect of the dye addition on the sample pH. By
performing the perturbation measurement on each sample we could directly calculate the
appropriate adjustment for each sample individually. The final temperature of the solution in the
cuvette was measured with a bead thermistor upon completion of the second dye reading and
recorded on the datasheets to define any deviation from the specified reading temperature. In
addition, at the freshwater site an unpreserved sample collected in a 300 ml BOD bottle was
incubated at the same temperature as the equilibration chamber and cell jacket until it reached a
constant temperature of 25°C, and the pH was subsequently read on a recent two-point calibrated
Metrohm electrode. The electrode was calibrated daily at 25.0
o
C.
After each use the Van Dorn sampler, fill tubing and cuvettes were thoroughly rinsed
with deionized water to prevent any build-up of salts or dye.
Ancillary Environmental Data
- At each of the mooring test sites, two calibrated CTD
packages were attached to the test rack and positioned to best characterize the salinity
surrounding the mooring. The CTDs provided an independent record of conductivity and
temperature measured at 15 minute intervals. In addition, four RBR Solo temperature sensors