ISO 18191

Water quality — Determination of pHT in sea water — Method using the indicator dye m-cresol purple

General information

Current stage: 60.00 Effective date: 26 maj 2026

Originator: ISO

Owner: ISO/TC 147/SC 2

Type: International Standard

Scope

ISO 18191:2015 specifies a spectrophotometric determination of the pHt of sea water on the total hydrogen ion concentration pH scale using the indicator dye m-cresol purple. The total hydrogen ion concentration, [H+]t, is expressed as moles per kilogram of sea water. The method is suitable for assaying oceanic levels of pHt 7,4 to 8,2 for normal sea water of practical salinity ranging from 20 to 40.

Life cycle

PREVIOUSLY

PUBLISHED
ISO 18191:2015

NOW

IN_DEVELOPMENT
ISO 18191
60.00 Standard under publication
26 maj 2026