Ion-Selective Electrode for Anionic Surfactants Using Hexadecyl Trimethyl Ammonium Bromide-Sodium Dodecylsulfate as an Active Ionophore

Table 5

Comparison of the results obtained by the potentiometric and two-phase titration of commercial detergents.

Sample	SDS (wt%)
	Potentiometric titration	Two-phase titration
1^a	14.37	14.23
2^a	14.34	14.20
3^a	14.39	14.26
RSD (%)^b	2.05	2.45

^aNumber 1, 2, 3: washing liquid (SDS, glycerine, sodium chloride, diethanolamid, and additives).
^bRelative standard deviation of potentiometric method for triplicate measurements.