Instrument: Automatic titrator

Instrument Short Name: Automatic titrator
(http://vocab.nerc.ac.uk/collection/L05/current/LAB12/)
Instrument Description:

Instruments that incrementally add quantified aliquots of a reagent to a sample until the end-point of a chemical reaction is reached.

PI supplied instrument name: Closed-cell potentiometric Gran titration
Dataset-specific description

The temperature within experimental tanks was measured every
other day with a NIST-calibrated partial-immersion organic-
filled glass thermometer (precision + 0.3%, accuracy + 0.4%).
Salinity was measured every other day with a YSI 3200 conduc-
tivity meter with a YSI 3440 cell (K 1⁄4 10) that was calibrated
with seawater standards of known salinity provided by the labora-
tory of Prof. A. Dickson of Scripps Institute of Oceanography.
Seawater pH was measured every other day with a Thermo Scien-
tific Orion 2 Star benchtop pH meter with an Orion 9156BNWP pH
probe, calibrated with 7.00 and 10.01 Orion NBS buffers traceable
to NIST standard reference material (for slope of the calibration
curve) and with seawater standards of known pH also provided
by Prof. Dickson’s laboratory (for y-intercept of the calibration
curve). Seawater DIC was measured via coulometry (UIC 5400)
and TA was measured via closed-cell potentiometric Gran titration
calibrated with certified Dickson TA/DIC standards. Measure-
ment of DIC and TA of the certified reference materials (CRMs)
were consistently within 0.3% of certified values. Differences
between the measured and certified TA and DIC values of
the CRMs were used to correct measurements of experimental
seawater solutions.