Method of colloid titration (a new titration between polymer ions)

Abstract

A general discussion about the method of colloid titrations is given in this report. A new titration method is based on the stoichiometric combination of positive and negative colloid ions. The end point is decided by indicators (known as metachromatic coloring matters) like toluidine blue. The standard colloid reagents are P.V.S.‐K (potassium salt of polyvinyl alcohol sulfate) and Macramin (N‐polymethylated chitosan derivatives). The typical operations of this method are described briefly: the direct, indirect, and differential titration methods. The colloid titration curve is somewhat different from the acid‐base titration curve obtained potentiometrically, but it is characteristic and reproducible under definite conditions and so it is useful in quantitative and qualitative analysis. This titration may be carried out even under extraordinary dilute conditions (5 × 10−4 N) and the entire process is quite similar to the usual acid‐alkali titration. The precision is below ±ca. 5% if the method is carefully followed.

Polyelectrolyte assisted charge titration spectrometry: Applications to latex and oxide nanoparticles

“…To determine the charge density of iron oxide particles for instance, Lucas et al used potentio--conductometric titration with dispersions containing 5--10 g of iron oxide dry matter [18]. Colloid titration is another method that was introduced by Terayama some 50 years ago [22]. This technique was applied to titrate ion--containing polymers in aqueous solutions.…”

pH-Potentiometirc Study of Polyion Complexes between Chitosan and Poly(vinyl sulfate) or Dodecylbenzene Sulfonate

“…The endpoint of colloidal titration is commonly detected by the metachromagy of Toluidine Blue (TB) as a visual indicator. 12 When the metachromagic change is indistinct, the endpoint can also be determined by potentiometry using an ion sensor. We had demonstrated the advantages of the potentiometric colloidal titration of chitosan by the use of a TB selective electrode.…”

“…The measurement methods of the deacetylation degree of chitosan include NMR, [5][6][7] IR, 8 acid base titration, 9,10 and colloidal titration. [11][12][13] Colloidal titration on which chitosan stoichiometrically reacts with potassium PVS is one of the most conventional methods. The endpoint of colloidal titration is commonly detected by the metachromagy of Toluidine Blue (TB) as a visual indicator.…”

Humic substance charge determination by titration with a flexible cationic polyelectrolyte

“…An alternative way to obtain information on the absolute charge density of HS is the so-called "colloid titration" (Terayama, 1952). With this technique, e.g.…”