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Preparation of 2‐amino‐2‐hydroxymethyl‐1,3‐propanediol ( TRIS ) pH T buffers in synthetic seawater
Author(s) -
Paulsen MayLinn,
Dickson Andrew G.
Publication year - 2020
Publication title -
limnology and oceanography: methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.898
H-Index - 72
ISSN - 1541-5856
DOI - 10.1002/lom3.10383
Subject(s) - hydroxymethyl , tris , seawater , buffer (optical fiber) , calibration , chemistry , chromatography , computer science , stereochemistry , biochemistry , mathematics , biology , ecology , statistics , telecommunications
Buffers of known quality for the calibration of seawater pH T measurements are not widely or commercially available. Although there exist published compositions for the 0.04 mol kg‐H 2 O −1 equimolar buffer 2‐amino‐2‐hydroxymethyl‐1,3‐propanediol (TRIS)‐TRIS · H + in synthetic seawater, there are no explicit procedures that describe preparing this buffer to achieve a particular pH T with a known uncertainty. Such a procedure is described here which makes use of easily acquired laboratory equipment and techniques to produce a buffer with a pH T within 0.006 of the published pH T value originally assigned by DelValls and Dickson (1998), 8.094 at 25°C. Such a buffer will be suitable for the calibration of pH measurements expected to fulfil the “weather” uncertainty goal of the Global Ocean Acidification Observation Network of 0.02 in pH T , an uncertainty goal appropriate to “identify relative spatial patterns and short‐term variation.”