Nonsteroidal anti-inflammatory drugs (NSAIDs) are a class of widely used medications with analgesic, anti-inflammatory, and antipyretic effects. Flufenamic acid (FFA), a member of the fenamate class, is used to manage inflammation, pain, and other soft tissue disorders. However, due to its fluorinated structure, FFA is not easily broken down by conventional wastewater treatment, allowing it to persist and contaminate natural water bodies. This contamination is a growing concern, as FFA is toxic to aquatic organisms like green algae and can affect the hepatic and gastrointestinal systems of fish. While existing analytical methods like chromatography and spectrophotometry can detect FFA, they are often expensive, complex, and time-consuming. This has spurred the development of more efficient and cost-effective electrochemical sensors for environmental monitoring. In a recent article in ACS Omega, authors Francisco Walison Lima Silva et al. present a novel and highly effective solution: a disposable electrochemical sensor made from a screen-printed electrode modified with bamboo biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More (SPE/BCB).

The bamboo biochar used in this study was produced by slow pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More at 600°C in a nitrogen atmosphere. The material’s characterization revealed a specific surface area of 125.7 m²/g and a porous structure typical of biochar, which is essential for its function. The presence of functional groups like hydroxyls, amines, and aromatic rings indicates that the biochar has potential for redox interactions and can improve the sensor’s conductivity and reactivity.

The performance of the SPE/BCB sensor was evaluated using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The SPE/BCB sensor showed a greater electrooxidation of FFA compared to the bare electrode, exhibiting a higher current signal. Electrochemical impedance spectroscopy (EIS) further confirmed this enhancement, showing a charge transfer resistance of 147 Ω for the SPE/BCB, which is more efficient than the 237 Ω of the bare electrode. The sensor demonstrated optimal performance at pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More 7, with a linear relationship between peak potential and pH, indicating a proton-to-electron ratio of 1:1 during the oxidation process.

The SPE/BCB sensor demonstrated an impressive analytical performance, with a sensitivity of 2.30 µA/µmol L−1 and a broad linear range of 0.05 to 13.32 µmol L−1. Its ultralow detection limit was calculated to be 1.3 nmol L−1, which is comparable to, and in some cases better than, other advanced electrodes reported in the literature. In addition, the sensor proved to be highly selective, showing no significant interference from common substances like dopamine, ascorbic acid, uric acid, and various insecticides and drugs, even at concentrations 100 times higher than that of FFA. The sensor also showed excellent reproducibility and stability, with a relative standard deviation (RSD) of 3.0% across multiple electrodes and 6.0% over a 30-day period.

The authors successfully tested the sensor’s accuracy in real-world environmental samples. Recovery values ranged from 95% to 101% for tap water and 90% to 96% for river water, demonstrating its ability to provide consistent and accurate results in complex aqueous matrices. This performance was also comparable to the UV-vis method, with no significant difference found between the two techniques. The SPE/BCB sensor’s combination of high sensitivity, affordability, and disposability makes it a promising tool for effective environmental monitoring.

Source: Silva, F. W. L., Teixeira, L. E. d. C., Bernardino, C. A. R., Mahler, C. F., Borges, R. C., Santelli, R. E., & Cincotto, F. H. (2025). A Novel Disposable Bamboo Biochar-Based Electrochemical Sensor for Detecting the Nonsteroidal Anti-Inflammatory Drug Flufenamic Acid in Environmental Samples. ACS Omega, 10(XX), XXX-XXX.