# Electrochemical Determination of Nitroguanidine among Other Explosives Using Polymerized 2‑Nitrophenol/Reduced Graphene Oxide-Modified Glassy Carbon Electrode

## TL;DR

A new sensor detects nitroguanidine, an explosive chemical, with high accuracy even in complex mixtures and soil samples.

## Contribution

A novel electrochemical sensor using polymerized 2-nitrophenol and reduced graphene oxide for selective nitroguanidine detection is developed.

## Key findings

- The sensor detects nitroguanidine with a linear response from 0.5 to 100 mg L–1 and a detection limit of 0.12 mg L–1.
- The sensor shows high selectivity in the presence of soil interferents and electroactive materials.
- The method was validated using clay soil samples and compared with LC–MS, confirming its reliability for environmental monitoring.

## Abstract

In this study, a novel sensor working electrode was fabricated
by functionalizing a glassy carbon (GC) electrode surface with electrochemically
reduced graphene oxide (ERGO) and poly-2-nitrophenol (P2NP, electrochemically
polymerized, used as a hydrogen-bonding substrate) using the proposed
square-wave voltammetry (SWV) method toward the highly selective and
sensitive electrochemical sensing of nitroguanidine (NG), a friction-
and impact-insensitive high explosive increasingly used in energetic
formulations, even in the presence of other types of energetic materials.
NG showed a characteristic reduction peak at approximately −1.27
V. A linear response was obtained between 0.5 and 100 mg L–1 (4.80 × 10–6–9.61 × 10–4 mol L–1), and the limit of detection (LOD) was
found as 0.12 mg L–1 (1.15 × 10–6 mol L–1). The developed GC/ERGO/P2NP sensor electrode
successfully determines NG in both synthetic and real energetic material
mixtures (20-fold) with high recovery rates. The sensor maintained
its high selectivity (20 mg L–1 NG) even with the
addition of potential soil interferents at a 50-fold excess (10-fold
for Fe3+, Pb2+, and Cu2+) including
Cl–, SO4
2–, NO2
–, NO3
–, NH4
+, K+, Na+, Ca2+, and Mg2+, and electroactive camouflage materials (10-fold)
such as paracetamol, caffeine, acetylsalicylic acid, aspartame, d-glucose, and detergent. Finally, clay soil samples contaminated
with NG were analyzed using the proposed method, and the results were
statistically compared with LC–MS using Student’s t-test and F-test, confirming its reliability
for real-world environmental monitoring.