Nitric acid extraction with monoamide and diamide monitored by second harmonic generation at the water/dodecane interface

► Liquid-liquid (LL) interfaces are investigated during ion extraction. ► Surface second harmonic generation is used to characterize interfacial activity. ► Amides extractants are studied close to the critical aggregation concentration (CAC). ► A fluctuating SHG intensity is observed for concentrations close to CAC. ► Bulk real time titration shows a high rate of extraction close to the CAC.