Complexometric titrations: new reagents and concepts to overcome old limitations

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Materials Science

Background:

• Complexometric titrations rely on chelators and indicators, with ethylenediamine tetraacetic acid (EDTA) being a common but non-selective choice.
• Existing chelators often require masking agents and precise pH control due to multiple pKa values, limiting their practical application.
• There is a need for novel chelators and indicators that are selective, sensitive, and pH-independent for complexometric analyses.

Purpose of the Study:

• To present recent developments in chelators and indicators for complexometric titrations.
• To highlight new approaches overcoming limitations of traditional reagents and methods.

Main Methods:

• Development of novel chelators and indicators utilizing highly selective ionophores.
• Immobilization of ionophores within ion-selective nanosphere emulsions for heterogeneous phase titrations.
• Application of thin-layer electrochemistry as a reagent-free sensing tool for in situ titrations.

Main Results:

• Heterogeneous phase titrations using ionophore-based nanosphere emulsions demonstrate enhanced selectivity and pH independence.
• Thin-layer electrochemistry provides a direct, reagent-free method for complexometric sensing, simplifying traditional titration protocols.
• These advancements enable more robust and user-friendly complexometric analyses.

Conclusions:

• Recent innovations in chelator and indicator design are significantly advancing complexometric titration capabilities.
• The shift to heterogeneous systems and instrumental control offers improved selectivity, sensitivity, and operational simplicity.
• Future developments promise reagent-free, in situ complexometric analysis with complete instrumental control.