Moisture content measurement model of whole package of Chinese medicinal materials based on microwave transmission technology

Abstract

In view of the relatively low representativeness of manual sampling inspection, and long time-consuming in oven detection of moisture content, which delayed the subsequent production period, this paper proposed a scheme for rapid moisture quantitative detection for Chinese medicinal materials by microwave transmission technology, and took 8 different types of Chinese medicinal mate-rials as examples to analyze the feasibility and reliability of the scheme for the detection results of moisture content of the whole package of Chinese medicine. In the experiment, the least square method was used to establish the measurement model of microwave absorption rate-moisture content for each kind of medicinal material. The results showed that the microwave transmission measurement of moisture content achieved high-precision measurement of the moisture content of Schisandrae Chinensis Fructus, Ziziphi Spinosae Semen, Poria, Pheretima, Lilii Bulbus, Scutellariae Radix, and Galli Gigerii Endothelium Corneum. The measurement model of Ziziphi Spinosae Semen had the highest accuracy, and the R~2 and root mean square error of the validation set were 0.951 5 and 0.15%, respectively. At the same time, this study found that the microwave absorption intensity of animal medicines including Pheretima and Galli Gigerii Endothelium Corneum was much weaker than that of plant medicines such as Schisandrae Chinensis Fructus, but there was also a good linear relationship between microwave absorption and moisture content, which proved the universality of this method. However, this method was not suitable for Phellodendri Chinensis Cortex because its package contained iron wire. For the whole package of medicinal materials with uniform density and no metal inside, the microwave transmission technology for moisture content measurement can be used to detect the moisture content, which is an effective alternative method to detect the moisture content of medicinal materials.