Researchers in the Oregon State University College of Science have developed a new electrochemical sensor for rapidly and accurately detecting a naturally occurring compound widely used in the food, beverage and fragrance industries.
The compound is eugenol, which gives cloves their telltale flavor and smell, and measuring its presence in commercial products is important for manufacturers and regulators.
Findings were published in Materials Today Chemistry.
Current techniques for measuring eugenol and other phenolic compounds, many of which contribute to the color, flavor, aroma and antioxidant properties of various foods, rely on sophisticated laboratory methods such as gas chromatography or high-performance liquid chromatography. The testing is accurate but relies on specialized personnel that makes the process expensive and time consuming.
While many nanomaterial-based sensors require precious metals and/or complex fabrication methods, scientists at OSU designed a nanocomposite sensor based on zinc phosphate and carbon black, which are relatively abundant and inexpensive. The composite is produced in a water-based solution via precipitation.
The comparatively low cost of components and ease of synthesis suggest the technology has high potential for scalability, the scientists say. Faster testing and simpler quality-control workflows for food producers may one day be among the results of the novel nanocomposite.
The sensor works by capturing eugenol in its mesoporous phosphate framework, concentrating it at the electrode surface, and using the conductive carbon black to quickly carry away electrons.
"Our research has long focused on rationally designing materials by controlling their composition, structure and properties to achieve specific functions," said Mas Subramanian, University Distinguished Professor and Milton Harris Chair in Materials Chemistry at Oregon State University. "In this case, we designed a material in which the different components work together to capture the target molecule and efficiently convert that chemical interaction into an electrical signal.
"We want to design materials for a particular function, but we also want to see whether that function translates into a useful result in the real world," he added.
In the study led by postdoctoral research Gopika Meenakumari Gopakumar, the researchers report that the sensor recovered 96.4% to 99.9% of eugenol from real food samples - cinnamon, peach, coffee beans, strawberry and canned tuna.
"Demonstrating accurate performance in complex foods shows the technology is likely not far away from practical application," Gopakumar said. "We are not simply combining two components. We designed the composite so that each component contributes a different function, allowing us to achieve sensitive detection while maintaining good stability and reproducibility."
The researchers say the platform could be adapted to detect other phenolic compounds for food safety and pharmaceutical analysis.
Collaborating on the study were scientists at National Taipei University of Technology, Ming Chi University of Technology, and King Saud University.
The U.S. National Science Foundation and the Ongoing Research Funding program at King Saud University supported the study.
