Knowledge Gateway
Unlock your learning potential with industry insights and standards that matter. Share your email to begin.
Unlock your learning potential with industry insights and standards that matter. Share your email to begin.
Status : Active
Standard Type : Main
Document No : ISO 18191:2026
Document Year : 2026
Pages : 13
Edition : 2
Section Volume : Physical, chemical and biochemical methods (ISO/TC 147/SC 2.)
This document specifies a spectrophotometric determination of the pHT of seawater on the total hydrogen ion concentration pH scale. The total hydrogen ion concentration, [H+]T, is expressed as moles per kilogram of seawater. The method is suitable for assaying oceanic levels of pHT from 7,4 to 8,2 for normal seawater of practical salinity ranging from 20 to 40.