The findings on the filter, developed by researchers at Bar-Ilan University, were presented in the peer-reviewed journal, Environmental Science: Nano.

The filter, a highly sensitive plasmonic-based detector, was designed specifically to detect harmful piperidine molecular residue in water.

Piperidine and its derivatives have various applications in the pharmaceutical industry. Piperidine’s versatility makes it used as a building block in organic synthesis to create more complex molecules and is commonly used to treat a wide range of medical conditions. It is also used in various chemicals, including dyes, pesticides, flavors, and fragrances, as well as treating metal to protect it from corrosion.

However, piperidine can be toxic if ingested, inhaled, or absorbed through the skin in high concentrations. It can also react with other chemicals to produce hazardous by-products. Improper disposal of piperidine can contaminate soil, water or air. Detecting even trace amounts of piperidine is imperative for safeguarding drinking water and food safety.

The nanofilter features triangular cavities etched in a silver thin film, shielded by a 5-nanometer layer of silicon dioxide, offering unparalleled sensitivity to piperidine by detecting low concentrations in water.

The development of this dime-sized device was spearheaded by Mohamed Hamode, a Ph.D. student at Bar-Ilan’s Department of Chemistry, in collaboration with Dr. Elad Segal. Employing a focused ion microscope, Hamode meticulously drilled nanometer-sized holes onto a metal surface, utilizing a custom-built computer program to shape the holes.

The minute apertures, smaller than the wavelength of visible light, intensify the electrical field on the surface, resulting in concentrated light in extremely confined areas. This amplification allows for the detection of low concentrations of molecules that were previously undetectable with optical probes.

The plasmonic substrate, characterized by its confined and enhanced electromagnetic field, presents an efficient alternative to existing substrates utilized in Surface Enhanced Raman Spectroscopy (SERS). This breakthrough opens avenues for the utilization of cost-effective and portable Raman devices, facilitating quicker and more affordable analysis.

“By harnessing nano-patterned metallic surfaces, we have demonstrated the detection of low concentrations of piperidine in water using affordable optics, offering a promising solution for environmental analytical setups,” said lead researcher Prof. Adi Salomon.

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