RESUMO
The quality standardization of seed and seedling is not only the basis of standardized production of Chinese materia medica, but also the important content of standardization of Chinese medicine. To grade quality of seed and seedling and establish grading standards are an important part of seed and seedling standardization of Chinese materia medica. This article reviewed the recent research progress in the quality grading of seed and seedling in different types of Chinese materia medica, in order to provide a reference for further research and development.
RESUMO
A carboxylesterase ( CaE ) ratiometric fluorescent probe based on semiconducting Poly ( 9 , 9-dioctylfluorenyl-2,7-diyl) (PFO) polymer quantum dots (Pdots) was prepared. The negatively charged PFO Pdots and the positively charged polyethyleneimine ( PEI) formed a nanocomposite Pdots@PEI by electrostatic interaction, and emitted fluorescence at 440 nm and 467 nm. In the presence of CaE, the substrate fluorescein diacetate ( FDA ) was hydrolyed into negatively charged fluorescein molecule, and could get closer to the positively charged Pdots@PEI due to electrostatic interactions, which could induce resonance energy transfer, resulting in the energy donor Pdots@ PEI fluorescence intensity gradually weakened and the fluorescence intensity of the FDA hydrolysis product increased. Based on the fluorescence intensity ratio of Pdots@PEI and the fluorescence enhancement of FDA hydrolysis products, a new method for selective detection of CaE was established. Under the optimal conditions, the linear range of the method on CaE testing was 0. 75-50 U/L with detection limits of 0 . 75 U/L ( S/N=3 ) . This method was used for the detection of the content of CaE in rabbit blood with satisfactory results.