Environmental electrochemical sensing of nitrotoluenes using dendrite-like carbon nanowall electrodes in real marine samples

Persistent contamination of the marine environment by nitrotoluenes hampers biological development and poses serious threats to marine organisms due to their toxicity and carcinogenicity. Effective monitoring is therefore critical to protect human health and preserve marine ecosystems. In this work, we report electrochemical detection of 2,4-dinitrotoluene (2,4-DNT) in real marine samples collected from the Baltic Sea, specifically from Bornholm Deep, Lübeck Bay, and Puck Bay. Detection was performed using sp 2 -rich dendrite-like boron-doped carbon nanowalls (D:CNW) electrodes fabricated through a one-step microwave plasma-enhanced chemical vapour deposition process. The D:CNW electrodes demonstrated excellent sensitivity towards 2,4-DNT, achieving a low limit of detection of 3.5 nM and high sensitivity of 61.3 ± 2.29 µA cm -2 µM -1 . The electrodes also exhibited good repeatability, with a relative standard deviation (RSD) value of 3.9% ( n = 8) and maintained electrochemical stability for up to 7 days in marine water. Additionally, factors influencing detection in real samples, including pH, ionic conductivity, suspended matter, water temperature, and ions characteristic of the marine matrix, were systematically investigated. The results highlight the strong potential of D:CNW electrodes for reliable and sensitive monitoring of nitrotoluene contaminants in complex marine environments. • D:CNW are promising electrodes for nitrotoluenes in marine environmental monitoring • D:CNW enables highly sensitive detection of 2,4-DNT in real seawater samples • The limit of detection of 2,4-DNT using D:CNW electrode was equal to 3.5 nM • D:CNW sensor shows good selectivity, repeatability, and stability in marine matrices • High ionic conductivity of seawater enhances the electrochemical response