ACT pH Sensor Verification Protocols, PV12-01
8
into the spectrophotometer from a supply tube within the test tank. Water from the test tank will
also flush a water jacket around the spectrophotometer cell to maintain the water in the cell very
near the temperature of the test tank. We will record 10 readings of the reacted dye over 1-2
minutes for each sampling timepoint and calculate a mean and standard deviation of each
reference measurement. The temperature of the sample stream will be monitored continuously
and the salinity of the sample stream will be measured on duplicate sub-samples with a
Guideline Portasal. Once during the stable phase of a given T-S test condition we will conduct a
more detailed burst sampling where 6-8 samples are collected over the course of an hour to
assess the fine-scale variability (temporal and spatial) of test tank conditions. During the pH
cycling phase of the test we will complete 2 reference sampling timepoints during each endpoint
(
approximately an hour after acid/base addition) of the increase or decrease. We expect each
phase (increase or decrease) to occur over roughly 2 hour intervals.
Lastly, duplicate water samples will be collected at the beginning and end of the stable
test condition period (day 1 and day 5) to characterize all of the CO
2
parameters. We will take
water samples for pCO
2
,
DIC and TA measurements and preserve and store them in accordance
with standard oceanic protocols (Dickson et al., 2007). These water samples will be shipped to
Oregon State University (Burke Hales, OSU) and SIO (Andrew Dickson) for analysis. In
addition, preserved water samples will be shipped to SIO (Andrew Dickson) and University of
South Florida (Robert Byrne, USF) for measurements of pH, thereby providing further indication
of the uncertainty of ACT’s reference sample measurements. However, because these samples
would not be handled identically to the reference samples analyzed real-time and directly from
the test tank, they will not be used in any direct assessment against the test instruments without
review from the TAC and consent from the manufacturer. Nutrients will also be measured on
these samples in Atkinson's lab.
6.3
Sample Handling and Custody Requirements
All collected reference water samples for the entire laboratory test will be handled in the
same manner. All reference samples should be processed according to methods defined within
these protocols and cited Standard Operating Procedure documents (Dickson et.al. 2007). Each
reference sample should be dated and coded according to site, test condition and sample
sequence. The actual sample container should be labeled with a number for identification. The
reference sample number should be used in all laboratory records and Chain-of-Custody (COC)
forms to identify the sample. The COC specifies 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 is
critical. The COC is a mechanism by which samples can 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
is also recorded on the COC and records are maintained in the laboratory with the names and
signature of persons leaving and receiving the custody. All logs shall be duplicated weekly. The
original log shall be retained at the ACT Partner site and a copy shall be sent to the ACT Chief
Scientist.
Accumulated samples to be analyzed by outside laboratories shall be shipped for analysis
each week to minimize holding time. Samples stored on site for more than one week shall be
