Novel electrochemical sensor based on nanodiamonds and manioc starch for detection of diquat in environmental samples.

Carbon nanomaterials thin films have been attracted considerable attention in the last years due to relative low cost and excellent electrical conductivity features. We report here on novel sensor architecture consisted of a glassy carbon surface modified with manioc starch and nanodiamonds nanoparticles. Structural and morphological properties of this thin film were investigated by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies. By using square-wave voltammetry as electroanalytical tool, the widely used herbicide diquat (DQ) was determined in environmental samples. The modified electrode presented a linear response to DQ in the concentration range of 5.0 × 10−7 to 4.6 × 10−5 mol L−1 with a limit of detection of 1.1 × 10−7 mol L−1. This novel sensor proved to be efficient to determine if DQ is present in rivers and drinking water samples. Unlabelled Image • Films based on nanodiamonds confined in biodegradable manioc starch are reported. • Diquat herbicide is determined by square-wave voltammetry. • Sub-micromolar detection of diquat is achieved by exploring the novel nanodiamonds based sensor. • The developed nanostructured sensor is efficiently applied for diquat quantification in environmental samples. [ABSTRACT FROM AUTHOR]