The Determination of Phenolphthalein in Chocolate Preparations by Nonaqueous Titration*

Potentiometric Electrode Systems In Nonaqueous Titrimetry

“…Hydroxyanthraquinone derivatives (1) and phenolic constituents in tar distillation products (135) have been titrated in pyridine, while a solvent consisting of mixed pyridine bases has been used for the titration of derivatives of barbituric acid (75). A solvent consisting of 85 per cent pyridine and 15 per cent ethylenediamine has been recommended for the determination of phenolphthalein in chocolate preparations (45). Butylamine has been used as a solvent for the titration of phenols (57), including those present in tobacco smoke (222).…”

Acid-Base Titrations in Nonaqueous Solvents

“…Pharmaceutical Applications. Doernberg, Hubacher, and Lysvj (44) determined phenolphthalein in chocolate preparations by a modified Moss, Elliott, and Hall procedure. A simple enclosed titration system is described using antimony-glass electrodes.…”

Review - Pharmaceuticals and Natural Drugs

“…The titrant is sodium dissolved in ethanolamine and diluted with pyridine. The indicator is thymol blue (97). Procaine and p-aminobenzoic acid are coupled after diazotization with l-naphthylamine; after the dye formation is completed, the derivatives are separated on the basis of their solubility in acids (procaine) and bases (p-aminobenzoic acid) (265).…”