Rapid detection of trace refrigerant impurities in low-temperature ethanol: A “background silence” method based on near-infrared spectroscopy

Abstract

Low-temperature ethanol method is the main process for the preparation of blood products. Ethanol is cooled using plate heat exchangers with refrigerant fluid, and the ethylene glycol in the refrigerant is a toxic reagent, so the problem of refrigerant fluid leakage has become a concern for blood product companies. The lack of detection methods of refrigerant impurities in ethanol at this process stage can lead to serious safety issues and losses in the event of a refrigerant leak. In this study, a pattern recognition method based on near-infrared spectroscopy (NIRS), the “background silence” method, was developed for the detection of refrigerant impurities in ethanol. The method considered normal impurity-free ethanol solution samples as the background and impurity samples as the interference, made the background “silent” through linear regression, highlighted the changes brought by the interference factor, and then established a “background silence” pattern recognition system by calculating the RSD value at the characteristic data points, which realised the detection of trace refrigerant impurities in ethanol solution. The specificity and sensitivity of the method reached 100 %, and the detection limit can reach 0.25 ‰. The NIRS “background silence” method enables the detection of trace refrigerant impurities in ethanol solutions with reduced computational complexity compared with the widely used PLS-DA discrimination method. This study provides new methodological guidance for the detection of impurities in low content components, and lays the foundation for the application of the “background silence” method in practical production.