Development of ionophore-based nanosphere emulsion incorporating ion-exchanger for complexometric titration of thiocyanate anion.

Ionophore-based ion-exchange nanosphere emulsion was prepared and tested for the determination of thiocyanate. The emulsified nanosphere contained the cationic additive tridodecylmethyl ammonium chloride (TDMAC), the plasticizer, and the ionophore Mn(III)-salophen or Mn(III)-salen. This emulsion was used as titrating agent for thiocyanate complexation with ionophores, which could be transduced using an ion-selective electrode (ISE) as an indicator electrode for the end point detection. The method showed no need for pH control and reliable selectivity, as thiocyanate could be determined in presence of other interfering ions with high accuracy. As well, the emulsion was stable and could be used for approximately couple of weeks. The developed emulsion could be used for the determination of thiocyanate in human saliva with standard deviation <4%. In sum, the proposed method could be used as an alternative for the argentometric titration and would open new avenues for the determination of neutral, anionic, and cationic species without necessity for water soluble ligands or pH control.