Procedure Library
P17.2

Active Matter Determination for Nonionic Surfactants — Cobalt Thiocyanate Complexation Method

Procedure 2 of 40 · Chapter 17 · §17.1.3

1 table 0 notes

Table 1

ReagentPreparation
Ammonium cobaltothiocyanate reagentDissolve 30.0 ± 0.1 g Co(NO₃)₂·6H₂O and 200.0 ± 0.1 g NH₄SCN in water, dilute to 1000 mL. Stable for 1 month at 25°C .
Dichloromethane (DCM)HPLC or analytical grade
Nonionic surfactant standardKnown purity (e.g., nonylphenol ethoxylate, NP-8 or NP-10, >98%)
Sodium chloride saturated solutionDissolve 360 g NaCl in 1 L water