Determination of tetracycline hydrochloride by terahertz spectroscopy with PLSR model

•Terahertz spectroscopy was applied for detecting the tetracycline hydrochloride.•Partial least-squares regression (PLSR) was used to build calibration models.•The PLSR model for powder samples could be used for quality control.•The PLSR model for solution samples was not robust and needed to be improved.•Revealing the potential for fast prediction of tetracycline hydrochloride residue. Antibiotic residues in agricultural and food products are of great concern to legislatures and consumers. Reliable techniques for rapid and sensitive detection of these residues are necessary to ensure food safety. In this study, tetracycline hydrochloride (TC-HCl) in powder and solution form was detected and quantified using terahertz (THz) spectroscopy. Partial least-squares regression (PLSR) was used to build calibration models. The results obtained in this study indicated that the PLSR model for powder samples was excellent and could be used for quality control. However, the PLSR model for solution samples was not robust and needed to be improved. Overall, THz spectroscopy combined with PLSR model had its potential for the rapid and non-destructive prediction of TC-HCl residue without sophisticated methods, although the accuracy was not high for solution samples which should be improved in future study.