A Terahertz Metasurface Sensor Based on Quasi-BIC for Detection of Additives in Infant Formula

Area of Science:

• Applied Physics
• Spectroscopy
• Materials Science

Background:

• Prohibited additives in infant formula pose significant health risks to infants.
• Terahertz (THz) spectroscopy offers rich fingerprint information for analyte detection.
• Limited research exists on detecting multiple analytes simultaneously using THz spectroscopy.

Purpose of the Study:

• To develop a THz spectroscopy method for detecting prohibited additives in infant formula.
• To investigate the use of a split ring metasurface supporting quasi-bound states in the continuum (BIC) for enhanced analyte detection.
• To demonstrate the simultaneous detection of multiple prohibited additives.

Main Methods:

• Fabrication of a split ring metasurface to generate high-quality factor quasi-BIC resonances.
• Utilizing an angle-scanning strategy to shift resonance frequencies and create an envelope curve.
• Applying the method to identify and quantify melamine and vanillin in mixtures.

Main Results:

• The metasurface generated quasi-BIC with a high quality (Q) factor.
• An envelope curve reflecting molecular fingerprints was plotted by angle scanning.
• Melamine and vanillin were identified in different proportions with a calculated resolution of 0.61, enabling simultaneous detection.

Conclusions:

• The proposed THz spectroscopy method provides a new solution for detecting prohibited additives in infant formula.
• The split ring metasurface and angle-scanning strategy enable sensitive and simultaneous detection of multiple analytes.
• This technique has significant potential for ensuring infant formula safety and quality control.