Green electrochemical biosensor for food safety monitoring of carcinogenic acrylamide and formaldehyde.

Food safety monitoring demands practical strategies for detecting chemical hazards such as acrylamide (AA) and formaldehyde (FA), both classified as probable human carcinogens with dietary exposures often exceeding tolerable limits. Conventional methods including GC-MS and HPLC, while sensitive, are costly, labour-intensive, and unsuitable for rapid on-site testing. Here, we report green electrochemical biosensors for AA and FA detection that integrate environmentally friendly graphene with 1-pyrenebutyric acid N-hydroxysuccinamide ester (PyrNHS) on disposable screen-printed carbon electrodes (SPCEs). Graphene was synthesized via liquid-phase exfoliation in an ethanol-water system, producing few-layer structures with abundant functional groups for stable bioreceptor attachment. PyrNHS enabled noncovalent anchoring and oriented immobilization of hemoglobin (Hb) for AA and formaldehyde dehydrogenase (FDH) for FA, overcoming limitations of costly and unstable nanomaterials. The AA biosensor operated through a signal-off mechanism using differential pulse voltammetry, with a detection limit of 4.39 μM over 0-25 μM. The FA biosensor employed a signal-on enzymatic mechanism with chronoamperometry, achieving 0.02 mM detection limit across 0.1-0.6 mM. Both sensors showed high selectivity, reproducibility (RSD <1.3 %), and effective performance in instant coffee, consistent with roasting chemistry and validated by Nash assay. This work demonstrates a sustainable, low-cost, and portable platform for point-of-care (POC) carcinogen monitoring.