P18.9
Active Matter Content — Anionic and Nonionic
Procedure 19 of 40 · Chapter 18 · §18.2.3
2 tables 0 notes
Table 1
| Parameter | Anionic (Two-Phase Titration) | Nonionic (CTAS Method) |
|---|---|---|
| Standard reference | ISO 2271:1989 | Modified SDA method |
| Reagent | Benzethonium chloride 0.004 mol/L | Cobaltothiocyanate reagent |
| Solvent system | Chloroform / water | Methylene chloride / water |
| Indicator | Mixed (aniline blue / dimidium bromide) | Colorimetric at 620 nm |
| Detection | Visual endpoint or potentiometric | Spectrophotometric |
| Interferences | Cationic surfactants | Cationics, anionics (remove by ion exchange) |
| Repeatability | ±1.5% of mean | ±3% of mean |
| Molecular mass required | Yes | No (calibration against reference standard) |
Table 2
| Expected AM (%) | Sample Mass (g) for 0.004 M Titrant |
|---|---|
| 15 | 10.0 |
| 30 | 5.0 |
| 45 | 3.5 |
| 60 | 2.5 |
| 80 | 1.8 |
| 100 | 1.4 |