Even small amounts of contaminants in water or other liquids can be detected (Detect small contaminants reliably and quickly) using spectroscopic methods. For use in forensics, the security industry, the food industry or medical research, methods such as enhanced Raman scattering (SERS) are still expensive and not fully reliable. A material science research group from the University of Kiel (CAU) has now succeeded in increasing the efficiency of the system by about 50. They have created a substrate with special nanostructures that increase the sensitivity and space and time resolution of the system. This leads to fast and high-quality results, even in the near future. In addition, the seeds can be recycled, which reduces the cost of research. The findings of the research team have been published in the journal Small.
The fruit does an important job
Raman spectroscopy – named after the Indian scientist and Nobel laureate Sir Chandrasekhara Venkata Raman – is a method for determining chemical composition and thereby identifying harmful substances. For this, a laser is used to irradiate the tissue sample. Conclusions about the identity of the material (Detect small contaminants reliably and quickly) can be made based on the so-called Raman signal that is returned. “The basis of the sample to be analyzed based on it, plays an important role here. Because there is an interaction with the laser light that affects the Raman signal,” explains Josiah Ngenev Shondo, a doctoral student at seat of the Joint Commission.
Bench researchers have now succeeded in creating seeds from various materials that are used to increase the Raman signal by 50% compared to the SERS method. “This is more than has been reported for this process,” says Prof. Oral Cenk Aktas. This increases the understanding of the system and its decisions about space and time. In this way, even a very small amount can be analyzed in a short time. After the research, the researchers destroyed the tissue samples with UV light. Aktas continues, “Expensive seeds are cleaned in this way and can be used many times for the first time – up to 20 times in our tests .”
Something that connects things that is obvious
The reason for the unique characteristics of the seed lies in its structure. “This is where different things with unique properties come together,” Dr. Salih Veziroglu, who studies materials under a grant from the CAU KiNSIS (Kiel Nano, Surface and Interface Science) research center. “For example, it includes photocatalytic titanium dioxide active layer and special plasmonic nanostructures.
” Researchers combined four different nanostructures on the surface of the substrate, including gold and silver particles , between which there is a light-matter interaction – the so-called plasmonic effect. With their words, the CAU team contributed to a new method of Raman spectroscopy, the PIERS (Photo Induced Enhanced Raman Spectroscopy) method that was recently introduced. The combination of plasmonic and photocatalytic effects leads to a better Raman signal and thus the resolution of the system.
Additional AI methods and conversion strategies
“This letter is the result of many years of research with different experts in our chair. We now want to put our results from the main research into practice, “explains the director, Prof. . Francois Faupel. The substrate can be incorporated into other Raman spectroscopy methods and enable a variety of applications. To bring it to the market, researchers are now looking to other researchers in companies and laboratories in research technology. They also plan to supplement their systems with artificial intelligence to create a comprehensive database for research purposes. In this way, individual molecules should also be able to be determined even faster and more precisely.
Doctoral student Shondo has already explored ideas for an application in his doctorate, which is nearing completion. In 2018, scientists came to the University of Kiel on scholarship from the German Academic Exchange Service (DAAD) to deal with environmental pollution in his country Nigeria. The production of large amounts of oil in the country pollutes the land, rivers and even drinking water. With the new seed developed by his colleagues in Kiel, he also sees the possibility of using portable Raman spectroscopy devices in Nigeria: “Since it can be used to detect and even extract small amounts of oil, the method can be used take action in time and prevent the worst environmental damage.
Source: University of Kiel (CAU)
