Three-dimensional fluorescence combined with alternating trilinear decomposition and random forest algorithm for the rapid prediction of species, geographical origin and main components of Glycyrrhizae Radix et Rhizoma (Gancao).

Glycyrrhizae Radix et Rhizoma (Gancao) is a functional food whose quality varies significantly between distinct geographical sources owing to the influence of genetics and the geographical environment. This study employed three-dimensional fluorescence coupled with alternating trilinear decomposition (ATLD) and random forest (RF) algorithms to rapidly predict Gancao species, geographical origins, and primary constituents. Seven fluorescent components were resolved from the three-dimensional fluorescence of the ATLD for subsequent analysis. Results indicated that the RF model distinguished Gancao from various species and origins better than other algorithms, achieving an accuracy of 94.4 % and 88.9 %, respectively. Furthermore, the RF regressor algorithm was used to predict the concentrations of liquiritin and glycyrrhizic acid in Gancao, with 96.4 % and 95.6 % prediction accuracies compared to HPLC, respectively. This approach offers a novel means of objectively evaluating the origin of food and holds substantial promise for food quality assessment.

Colorimetric assay based on peroxidase-like activity of dodecyl trimethylammonium bromide-tetramethyl zinc (4-pyridinyl) porphyrin for detection of organophosphorus pesticides.

A simple and sensitive colorimetric assay for detecting organophosphorus pesticides (OPs) was developed based on 3,3',5,5'-tetramethylbenzidine (TMB)/hydrogen peroxide (H2O2)/dodecyl trimethylammonium bromide (DTAB)-tetramethyl zinc (4-pyridinyl) porphyrin (ZnTPyP). In this system, based on the peroxidase-like activity of DTAB-ZnTPyP, H2O2 decomposes to produce hydroxyl radicals, which oxidize TMB, resulting in blue oxidation products. The OPs (trichlorfon, dichlorvos, and thimet) were first combined with DTAB-ZnTPyP through electrostatic interactions. The OPs caused a decrease in the peroxidase-like activity of DTAB-ZnTPyP due to spatial site blocking. At the same time, π-interactions occurred between them, and these interactions also inhibited the oxidation of TMB (652 nm), thus making the detection of OPs possible. The limits of detection for trichlorfon, dichlorvos, and thimet were 0.25, 1.02, and 0.66 µg/L, respectively, and the corresponding linear ranges were 1-35, 5-45, and 1-40 µg/L, respectively. Moreover, the assay was successfully used to determine OPs in cabbage, apple, soil, and traditional Chinese medicine samples (the recovery ratios were 91.8-109.8%), showing a great promising potential for detecting OPs also in other complex samples.

[Research progress on common pesticide residues in Chinese medicinal materials].

Chinese medicinal materials are the precious resources of China and favored by patients at home and abroad because of their natural sources and curative effects. Pesticides are often used to prevent and control diseases and insect pests and regulate the growth of Chinese medicinal plants, so as to improve the yield and quality of Chinese medicinal materials. Most of the pesticides can play a role in pest control through systemic action, stomach toxicity, contact, fumigation and other ways, especially the systemic pesticides can kill hidden pests by entering the Chinese medicinal plants. Despite the good pest control effect, it is difficult to remove the systemic pesticides by simple cleaning, which poses a great risk to the safety of Chinese medicinal materials. At the same time, excessive or non-standard use of pesticides leads to serious pesticide residues in Chinese medicinal materials, which affects not only the quality and efficacy of the materials and harm human health but also the international development of Chinese medicinal materials industry. Pesticide residues have become a bottleneck affecting the industry development and hindering the export of Chinese medicinal materials. Therefore, it is of great significance to study how to quickly, sensitively, and accurately detect and remove pesticide residues in Chinese medicinal materials. We reviewed the common pesticide residues in Chinese medicinal materials in recent years in terms of characteristics, harm, and detection and removal techniques, and discussed the future development of the detection and removal deve-lopment. With this review, we aimed to provide a reference for the quality control of Chinese medicinal materials and promote the healthy development of Chinese medicine industry.