A terahertz multi-band metamaterial absorber and its synthetic evaluation method based on multivariate resonant response fusion for trace pesticide detection

Abstract

A synthetic multivariate response evaluation of a multi-band terahertz (THz) metamaterial absorber (MMA) for highly sensitive and accurate detection of trace pesticides including indole-3-acetic acid, thidiazuron, benomyl, and chlorpyrifos in solution is presented. The THz spectral response of the prepared MMA sensor illustrated that with an increase in pesticide concentration (10∼520 ng/L), all absorption bands (0.91, 1.59, 1.99, and 2.42 THz) exhibited a red-shift in frequency, part of which showed a decrease in absorption intensity. The modeling results between the pesticide concentrations and spectral responses demonstrated that the proposed multivariate resonant response fusion (MRRF) framework outperformed all the univariate regressions in improving accuracy and simplifying evaluation through the effective multivariate selection and statistical fusion. The highest detection accuracy was achieved for chlorpyrifos (CPF). Consequently, trace CPF in four vegetable extracts was detected to further verify the stability and reliability of the multi-band MMA combined with MRRF. The results indicated that the predicted recoveries using our approach were accurate, and the detection limits of all pesticide solutions reached 10 ng/L. This work presents a new prospect for highly sensitive detection of trace hazardous materials and the potential application of THz metamaterial technology in food safety inspection.