Paper-based printed electrochemical sensor for the detection of hydroxymethyl furaldehyde in foods using nitrogen and sulphur co-doped graphene quantum dots

Abstract

In this study, we have developed a paper-based screen-printed electrode (SPE) system for the detection of 5-hydroxymethylfurfural (HMF), a potential carcinogen commonly found in food products, which is formed during the acidic decomposition of monosaccharides. The SPE was modified with nitrogen and sulphur co-doped graphene quantum dots (N,S-GQDs), synthesized using a simple hydrothermal process with amino acid precursors, tryptophan and methionine to achieve an innovative doping of nitrogen and sulphur respectively within the aromatic skeleton of the GQDs. The resulting N,S-GQDs exhibited excellent sensitivity (0.756 μAμM−1 cm−2) and selectivity for HMF detection through the paper-based SPE, which is a cost-effective, portable, and real-time sensing platform. In addition, the developed N,S-GQD/SPE sensor showed a ∼ 2.5-fold higher current response than the conventional glassy carbon electrode (GCE) system. The developed SPE sensor demonstrated a limit of detection (LOD) of 1 μM which is 10 times better than GCE, along with a broad linear detection range. Furthermore, the N,S-GQD/SPE effectively detected HMF in real samples, achieving recovery rates of approximately 99 % across all tested matrices. These results highlight the potential of the proposed system for real-time monitoring of HMF in food, paving the way for its application in food safety.