Rapid detection method for glyphosate developed
Source: BAM
Glyphosate (GPS) is the most widely used herbicide around the world, whose use increased dramatically after the introduction of genetically modified crops engineered to resist its effects after application. In recent years, there have been growing concerns over GPS toxicity following its classification by the International Agency for Research on Cancer (IARC) as a probable carcinogen as well as reports of its ecotoxicological effects. This has resulted in increased efforts to develop quick and sensitive methods for its detection.
Since GPS lacks a molecular subunit that can be directly interrogated by a sensitive spectroscopic method, prior functionalization of the molecule is necessary for analysis by conventional chromatographic techniques, which are resource-intensive and difficult to miniaturize. Molecularly imprinted polymers (MIPs) - polymer matrices containing binding sites analogous to a target analyte - are a useful tool for the capture and indication of a wide variety of molecules and can provide a feasible alternative to conventional analytical methods for GPS, especially for onsite use. MIPs are prepared by synthesizing a crosslinked polymer matrix in the presence of a target analyte, utilizing functional monomers that interact specifically with the analyte to generate high affinity binding sites. In this work, a polymerizable fluorescent indicator dye whose signal is enhanced by GPS in a concentration-dependent manner was incorporated into a 2-3 nm thin MIP layer grafted onto the surface of 270 nm silica particles and used in suspension assays.
Consequently, the MIP particles could be used to analyze for GPS directly, eliminating the need for prior functionalization of GPS. Moreover, the location of the binding sites within the thin MIP layer on the particle surface facilitated rapid diffusion of GPS into the binding cavities, achieving a <5 minutes assay time. Good selectivity for GPS compared to other commonly used herbicides and structurally similar molecules was accomplished. The particles were used for sensing of GPS in aqueous media at micromolar concentrations and thus can be applied in quantitative assays for GPS at toxicologically relevant levels. The assay shows potential for miniaturization into microfluidic devices, paving the way for future on-field applications by untrained personnel.
Scheme of the fluorescence enhancement of molecularly imprinted core-shell particles in presence of glyphosate Source: BAM, Division Chemical and Optical Sensing
Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents
Martha Kimani, Evgeniia Kislenko, Kornelia Gawlitza & Knut Rurack
published in Scientific Reports, Vol. 12, Issue 1, article 14151, pages 1-15, 2022
BAM division Analytical Chemistry; Reference Materials
BAM division Chemical and Optical Sensing