P-044

Annalakshmi Muthaiah

annalakshmi.muthaiah@chemia.uni.lodz.pl

Thangaraj S.T. Balamurugan, Karolina Czarny-Krzymińska, Karolina Marciniak, Lukasz Poltorak

Faculty of Chemistry, University of Lodz, Poland

Electroanalytical Sensing of Nitrate in Cyanobacteria Growth Media via Electrified Liquid-Liquid Interfaces

Nitrate (NO₃⁻) is essential for plant growth but poses serious environmental and health risks when present in excess. Agricultural runoff, industrial discharge, and wastewater contamination have led to widespread nitrate pollution, causing eutrophication, algal blooms, and oxygen depletion in water bodies1. Additionally, high nitrate levels are linked to human health concerns such as methemoglobinemia and potential carcinogenic effects [2]. Therefore, efficient nitrate monitoring is crucial for water quality management and environmental sustainability.

This study presents an innovative electrochemical sensing approach based on the electrified liquid-liquid interface (eLLI) combined with voltammetry for real-time nitrate detection in cyanobacteria growth medium. Unlike conventional laboratory-based methods, the eLLI sensor offers a portable, selective, and rapid detection platform suitable for onsite applications [3]. Nitrate detection at eLLI originates from its interfacial ion transfer, providing a distinct advantage over redox-based sensing. The sensor demonstrated a linear detection range of 20–500 µM, with detection and quantification limits of 1.5 µM and 14.6 µM, respectively [4].

A major challenge in nitrate sensing is interference from competing anions, particularly chloride. To address this, we developed an in situ chemical precipitation strategy to eliminate chloride interference, significantly improving detection accuracy. The sensor was validated in Z8 algae growing medium, commonly used for Microcystis aeruginosa cyanobacteria cultures, demonstrating its effectiveness for periodic nitrate monitoring in complex biological environments. This work highlights the potential of eLLI-based sensors as an efficient and field-deployable solution for nitrate monitoring. With further development, this technology could be integrated into real-time water quality monitoring systems, benefiting environmental conservation, agriculture, and public health. 

References

1. Rosales, D., Ellett, A., et.al., 2022. Applied and environmental microbiology, 88 (14), pp.e00356-22.

2. Patella, B., Russo, R.R., et.al., 2021. Talanta, 221, p.121643.

3. Sudalaimani, S., Kumar, K.S., et.al., 2021. Analyst, 146 (10), pp.3208-3215.

4. Annalakshmi, M., Balamurugan T.S.T., et al.2025. Sensors and Actuators B: Chemical, 423, 136863

Acknowledgements

Muthaiah Annalakshmi  and Lukasz Poltorak gratefully acknowledge the financial assistance through the PolonezBis fellowship (Project No. 2022/47/P/ST4/01065) co-funded by the National Science Centre (NCN) and the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 945339 - experiments at the electrified liquid-liquid interface, algae cultivation.