Development of an inexpensive and rapidly preparable enzymatic pencil graphite biosensor for monitoring of glyphosate in waters

• Published in: The Science of the total environment Vol. 855; p. 158865
• Main Authors: Zambrano-Intriago, Luis Angel, Amorim, Célia G., Araújo, Alberto N., Gritsok, Dmitrij, Rodríguez-Díaz, Joan Manuel, Montenegro, Maria C.B.S.M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10.01.2023
• Subjects: Biosensing Techniques - methods; Drinking Water; Electrochemical Techniques - methods; Electrodes; Glyphosate; Graphite - chemistry; Horseradish peroxidase; Humans; Hydrogen peroxide; Nanotubes, Carbon - chemistry; Pencil graphite electrode; Polysulfone; Reproducibility of Results; Horseradish peroxidase; Hydrogen peroxide; Polysulfone; Glyphosate; Pencil graphite electrode
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.158865

Glyphosate (GLY) is the most widely used non-selective broad-spectrum herbicide worldwide under well-reported side effects on the environment and human health. That's why it's necessary to control its presence in the environment. This work describes the development of an affordable, simple, and accurate electrochemical biosensor using a pencil graphite electrode as support, a horseradish peroxidase enzyme immobilized on a polysulfone membrane doped with multi-walled carbon nanotubes. The developed electrochemical sensor was used in the determination of GLY in river and drinking water samples. Cyclic voltammetry and amperometry were used as electrochemical detection techniques for the characterization and analytical application of the developed biosensor. The working mechanism of the biosensor is based on the inhibition of the peroxidase enzyme by GLY. Under optimal experimental conditions, the biosensor showed a linear response in the concentration range of 0.1 to 10 mg L−1. The limits of detection and quantification are 0.025 ± 0.002 and 0.084 ± 0.007 mg L−1, respectively, which covers the maximum residual limit established by the EPA for drinking water (0.7 mg L−1). The proposed biosensor demonstrated high reproducibility, excellent analytical performance, repeatability, and accuracy. The sensor proved to be selective against other pesticides, organic acids, and inorganic salts. Application on real samples showed recovery rates ranging between 98.18 ± 0.11 % and 97.32 ± 0.23 %. The analytical features of the proposed biosensor make it an effective and useful tool for the detection of GLY for environmental analysis. [Display omitted] •A new biosensor for monitoring glyphosate in water samples was presented.•A novel support based on HRP/PSF/MWCNT/PGE was developed.•Optimized surface conditions for HRP immobilization and electrochemical performance.•Wide linear relationship ranging from 0.1 to 10 ppm and a low LOD of 25 ppb.•Recovery in water samples between 95.21 and 103.45 %.