Premium
A comparison between field and laboratory pH measurements for seawater on the E ast C hina S ea shelf
Author(s) -
Chou WenChen,
Gong GwoChing,
Yang ChinYo,
Chuang KaiYuan
Publication year - 2016
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/lom3.10091
Subject(s) - alkalinity , seawater , chemistry , shelf life , china sea , analytical chemistry (journal) , environmental chemistry , environmental science , mineralogy , oceanography , food science , geology , organic chemistry
To evaluate the effect of sample storage on pH analysis, a comparison experiment between field and laboratory pH measurements was conducted on a total of 88 seawater samples collected on the East China Sea shelf during 16 July 2014–29 July 2014. The results show that although pH directly measured onboard was statistically higher than the pH later measured onshore with an average residual of 0.0052 ± 0.0057, after correcting for the perturbation caused by the addition of the HgCl 2 solution, the observed difference was within the uncertainty in pH measurement. Therefore, our result suggests that, similar to total alkalinity and dissolved inorganic carbon determinations, seawater samples can be stored for pH analysis with a precision that is comparable to the uncertainty of onboard measurement for a period of at least 20 d.