The herbicide glyphosate, N-(phosphonomethyl)glycine, has been widely used in the past 40 years, and has had many adverse effects on human health. Here, we constructed a convenient “on–off–on” fluorescent platform for detection of glyphosate via Cu2+ modulated squaraine dye fluorescence quenching. The squaraine dye F-0 exhibited strong fluorescence, which could be quenched by the addition of Cu2+. However, the addition of glyphosate restored the fluorescence intensity of F-0 due to the formation of a Cu2+-glyphosate complex. F-0 was utilized as a fluorescent probe for the quantitative detection of glyphosate, with the lowest detection limit of 13.16 nmol L−1. Furthermore, this method demonstrated high selectivity and anti-interference capabilities. The successful monitoring of glyphosate in real samples was achieved using this detection strategy.
Optical activity of hierarchical supramolecular assemblies based on organic dyes would create multiple functional architectures. In this work, three kinds of silica nanoparticles with or without functional groups were synthesized. For the first time, silica nanoparticles can induce positively charged squaraine (SQ) to aggregate to form supramolecular assemblies. Adenosine-5′-triphosphate (ATP) as building blocks was absorbed on the surface of silica nanoparticles through metal-anion coordination and electrostatic interactions, in which the aggregates of SQ was transferred to monomer. The thickness being composed of ATP and SQ on the outside of nanoparticles is about 5 nm. These supramolecular assemblies showed selective turn-on fluorescence response to ATP in near infrared (NIR) region over other ions through metal-anion coordination and electrostatic interactions. These functional silica nanoparticles possessing many advantages provide proof-of-principle “seed crystals” for construction of supramolecular assemblies and platforms for sensing with facile performance.
A new two-dimensional covalent organic polymer material (ST-1) was synthesized by the condensation of squaric acid and melamine. The preparation is simple and cheap. Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were employed to characterize the structure and properties of ST-1. This material presents the highest specific capacitance value of 177.6 F g−1 at a current density of 0.3 A g−1 in a three electrode configuration in a 6 M potassium hydroxide electrolyte. The retention rate of the specific capacitance can be maintained at about 60.24% when the current density is increased by 50 times. It is worth mentioning that ST-1 also demonstrates about 94% capacitance retention after 10 000 galvanostatic charge–discharge cycles.
危险品化学品经营许可证（带存储）