Investigation of nucleation processes with automated titrators

Significance of the topic

Controlling nucleation processes is crucial for producing materials with consistent particle sizes and improved functional properties. Particle size influences optical, electronic, and mechanical characteristics, making real-time monitoring of nucleation essential for applications in materials science, pharmaceuticals, and quality control.

Objectives and study overview

This study aims to demonstrate how automated titrators equipped with ion-selective electrodes can track free ion activity during precursor preparation and crystallization. By applying this approach to calcium carbonate formation, the investigation highlights the ability to identify key nucleation events and determine solubility products under defined conditions.

Methodology

The experiment follows a LaMer model framework in which a supersaturated precursor triggers nucleation and particle growth. A carbonate solution is adjusted to pH eleven via potentiometric titration. Calcium chloride is then dosed incrementally while monitoring free Ca2 activity and optical transmittance simultaneously. The pH is maintained at a constant level throughout the procedure to isolate ion dynamics.

Used instrumentation

• OMNIS Titrator with dosing module and optional sample robot
• 902 Titrando for pH Stat titration and potential measurement
• Combined Ca2 ion selective electrode for potentiometric monitoring
• Optrode for qualitative transmittance measurement

Main results and discussion

The recorded potential curve shows three distinct phases of calcium carbonate formation according to the LaMer scheme. Initially, free Ca2 concentration rises in the undersaturated solution. Upon reaching the nucleation threshold, a sharp decline in transmittance indicates particle formation. During the growth stage, the calcium ion potential stabilizes at a plateau corresponding to the solubility product of CaCO3 at pH eleven. Integrating potential and transmittance data into a single plot enhances interpretation of nucleation kinetics and growth regimes.

Benefits and practical applications

This method offers precise insight into nucleation onset and solubility limits, enabling optimized synthesis of uniform particles. Applications extend to process control in industrial crystallization, biomineralization studies, pharmaceutical crystal engineering, and geochemical analyses. The automated workflow improves reproducibility and throughput.

Future trends and applications

Advancements may include integration of high throughput screening with robotic sample handling, development of multi ion selective sensors, coupling with real time spectroscopy, and application of data analytics for predictive process control. These innovations will further refine our understanding of nucleation mechanisms across diverse material systems.

Conclusion

Automated titration combined with ion selective electrodes and optical monitoring provides a robust platform for investigating nucleation processes. By precisely tracking ion activity and particle formation in real time, researchers and manufacturers can achieve enhanced control over material properties and process consistency.

References

No references were cited in the original document.