Electrochemical Microsensor for Microfluidic Glyphosate Monitoring in Water Using MIP-Based Concentrators

Abstract

Glyphosate (GLY) is a broad-spectrum herbicide and is the most used pesticide worldwide. This vast usage has raised strong interest in the ecotoxicological impacts and human risks, with contamination of water being a major concern. Decentralized analytical techniques for water monitoring are of high importance. In this work, we present a small, low-cost, and time-effective electrochemical, chip-based microfluidic device for direct electrochemical detection of GLY downstream of a molecularly imprinted polymer (MIP) concentrator. We studied the electrochemical behavior of GLY and its metabolite aminomethylphosphonic acid (AMPA) using cyclic voltammetry with noble metal electrodes in acidic, neutral, and basic media. A chronoamperometric sensor protocol was developed for sensitive and selective GLY measurements on gold electrodes. The optimized protocol was transferred to a chip-based microsensor platform for online and real-time detection of GLY in a microfluidic setup. The results in the range from 0 to 50 μM GLY in 0.5 M H 2 SO 4 show high linearity and a sensitivity of 10.3 ± 0.6 μA mm −2 mM −1 for the chip-based microfluidic platform. Successful recovery of GLY concentrated from untreated tap water and its precise detection from low volumes demonstrates the advantages of our system.

Cyclic Voltammetry Study of Noble Metals and Their Alloys for Use in Implantable Electrodes

“…The CV scan of pure Au is highly asymmetric with a possible oxide formation peak in the anodic scan and a known oxide reduction peak in the cathodic scan ( Figure S2 ). 27 , 28 The Au scan had several distinct peaks in the cathodic scan dissimilar to those seen in the Pt and Pd scans, and no supporting literature could be found to suggest hydrogen adsorption. Alloy 6019, which contains Au (majority), Pd, Pt, and Ir, shows what appears to be an oxide reduction peak and then a hydrogen adsorption peak both smaller than those seen in the Pt and Pd families.…”

Portable Pesticide Electrochem-sensor: A Label-Free Detection of Glyphosate in Human Urine

“…The EU limit for glyphosate in water is 0.1 μg/L, while the U.S. limit is 700 μg/L. 2 For the evaluation of human exposure to glyphosate, in a study by the German environmental agency, a close group of young adults (in the years 2001−2015) were monitored, and of the 399 samples analyzed, roughly ∼30% showed glyphosate concen- trations above the limit of quantitation (>0.1 μg/L) analyzed via GC-MS. 9 A positive correlation has been reported between the urinary excretion of glyphosate and food consumption, which is important for biomonitoring in risk and safety assessments. 10 Increased levels of glyphosate in urine have been related to the level of bioavailable glyphosate absorbed by the body through various occupational sources and food residues.…”

“…Glyphosate is a well-known synthetic herbicide that was patented by the Monsanto Company in 1974 and is utilized in many products. Glyphosate is best known for its use in “Round-Up” pesticide products and is the herbicide that is used with Monsanto-branded GMOs. − The wide application of glyphosate and related herbicides has enhanced the growth of glyphosate resistant and tolerant weeds worldwide, consequently increasing applications at higher concentrations . Glyphosate has also become the most used pesticide in the world, with the United States being responsible for nearly 19% of the global consumption of glyphosate .…”

“…Several regulatory authorities have established safe limits or concentrations of this herbicide in water and various food products we consume every day. The EU limit for glyphosate in water is 0.1 μg/L, while the U.S. limit is 700 μg/L . For the evaluation of human exposure to glyphosate, in a study by the German environmental agency, a close group of young adults (in the years 2001–2015) were monitored, and of the 399 samples analyzed, roughly ∼30% showed glyphosate concentrations above the limit of quantitation (>0.1 μg/L) analyzed via GC-MS .…”

Nitrogen-Doped Graphdiyne Quantum Dots for Electrochemical Chloramphenicol Quantification in Water

“…Among the various analytical techniques reported for quantifying antibiotics including chromatography-based techniques, enzyme-linked immunosorbent assays, luminescence assays, surface-plasmon-resonance assays, fluorescent assays, and aptamer-based sensors, electrochemical methods are particularly suitable. ,, Specifically, having the advantages of high selectivity and sensitivity, rapid analysis, low cost, ease in use, and easy miniaturization, − electrochemical techniques can be used for high-fidelity antibiotic quantification.…”