Formation of an ion associated with the excess of 2-aminoperimidine hydrobromide (Ap) and sulfate ion in the sample solution and detection of the concentration of the remaining Ap ion by the optode. The developed optode method could be applied to determine sulfate ions in environmental water samples[1].
Purify the hydrobromide by boiling a saturated aqueous solution with charcoal, filtering and leaving the salt to crystallise. Store this dihydrate salt in a cool, stoppered flask in the dark place. The anhydrous salt is obtained by heating at 80o/4hours, and it is hygroscopic. The solubilities of the hydrobromide at 26o are 2.4% in EtOH, 0.6% in H2O, 0.3% in Et2O, 0.1% in Me2CO and 0.003% in *C6H6. [Dasgupta et al. Anal Chim Acta 94 205 1977, Dasgupta & West Microchim Acta 2 505 1978, Dasgupta et al. Anal Chem 50 1793 1978, Beilstein 24 H 193, 25 III/IV 2677.]
[1] Takashi Masadome, Hidekazu Ishikawa. “Determination of Sulfate Ion with 2-Aminoperimidine Hydrobromide Using an Optode Based on Tetrabromophenolphthalein Ethyl Ester Membrane.” Analytical Sciences 34 3 (2018): 383–385.
