Photogenerated carrier dynamics at the B4C3/g-C3N4 interface.

Developing van der Waals (vdW) heterostructures is an excellent approach for optimizing exceptional optoelectronic and photocatalytic properties of materials; therefore, researching the interface dynamics of charge carriers at the two-dimensional vdW heterojunction is of great significance. In this work, we perform time-dependent ab initio non-adiabatic molecular dynamics simulations to study the dynamics of charge transfer at the B4C3/g-C3N4 heterostructure. The simulations show that the charge transfer between B4C3/g-C3N4 layers is mainly caused by the non-adiabatic mechanism. The non-adiabatic mechanism leads to a higher charge-transfer efficiency and slows down the process of interlayer electron-hole recombination, thereby promoting the separation of photogenerated electron-hole pairs. Our investigation provides essential insights into understanding the dynamics of charge transfer for the B4C3/g-C3N4 heterostructure, which provides guidance for photocatalytic water splitting and optoelectrical applications.

Quantitative determination, principal component analysis and discriminant analysis of eight marker compounds in crude and sweated Dipsaci Radix by HPLC-DAD.

CONTEXT: Dipsaci Radix is derived from the dry root of Dipsacus asper Wall.ex Henry (Dipsacaceae). It has attracted increasing attention as one of the most popular and precious herbal medicines in clinical use. OBJECTIVE: To develop a HPLC-DAD method for quantitative analysis and quality control of eight active components in crude and sweated Dipsaci Radix. MATERIALS AND METHODS: The eight components in Dipsaci Radix were analyzed by HPLC-DAD on an Agilent Eclipse XDB-C18 column within a gradient elution of acetonitrile and 0.05% formic acid aqueous solution. ESI-MS spectra were acquired on a triple quadrupole mass spectrometer. Validation was performed in order to demonstrate linearity, precision, repeatability, stability, and accuracy of the method. The results were processed with principal component analysis (PCA) and discriminant analysis (DA). RESULTS: The eight components showed good linearity (R2 > 0.9991) in the ranges of 60.40-1208.00, 151.00-3020.00, 3.06-61.20, 30.76-615.20, 5.13-102.60, 10.17-203.40, 10.20-204.00, and 151.60-3032.00 mg/mL, respectively. The overall recoveries were in the range of 99.03-102.38%, with RSDs ranging from 1.89% to 4.05%. Through PCA, the degree of importance of the eight components in sequence was CA > AVI > IA > LA > LN > IC > IB > CaA. The crude and sweated Dipsaci Radix were distinguished obviously by DA. DISCUSSION AND CONCLUSION: The method, using HPLC-DAD analysis in combination with PCA and DA, could provide a more comprehensive and quantitative chemical pattern recognition and quality evaluation to crude and sweated Dipsaci Radix.

[Analysis of different forms Linderae Radix based on HPLC and NIRS fingerprints].

Three different forms of Linderae Radix were evaluated by HPLC combined with NIRS fingerprint. The Linderae Radix was divided into three forms, including spindle root, straight root and old root. The HPLC fingerprints were developed, and then cluster analysis was performed using the SPSS software. The near-infrared spectra of Linderae Radix was collected, and then established the discriminant analysis model. The similarity values of the spindle root and straight root all were above 0.990, while the similarity value of the old root was less than 0.850. Two forms of Linderae Radix were obviously divided into three parts by the NIRS model and Cluster analysis. The results of HPLC and FT-NIR analysis showed the quality of Linderae Radix old root was different from the spindle root and straight root. The combined use of the two methods could identify different forms of Linderae Radix quickly and accurately.

Investigation of the Effect of Rice Wine on the Metabolites of the Main Components of Herbal Medicine in Rat Urine by Ultrahigh-Performance Liquid Chromatography-Quadrupole/Time-of-Flight Mass Spectrometry: A Case Study on Cornus officinalis.

Ultrahigh-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (UPLC-QTOF/MS) was developed for rapid and sensitive analysis of the effect of rice wine on the metabolites of the main components of herbal medicine in rat urine. Using Cornus officinalis as a model of herbal medicine, the metabolite profiles of crude and processed (steaming the crude drug presteeped in rice wine) Cornus officinalis extracts in rat urine were investigated. The metabolites of Cornus officinalis were identified by using dynamic adjustment of the fragmentor voltage to produce structure-relevant fragment ions. In this work, we identified the parent compounds and metabolites of crude and processed Cornus officinalis in rats. In total, three parent compounds and seventeen new metabolites of Cornus officinalis were found in rats. The contents of the parent compounds and metabolites in vivo varied significantly after intragastric (i.g.) administration of aqueous extracts of crude and processed Cornus officinalis. Data from this study suggests that UPLC-QTOF/MS could be used as a potential tool for uncovering the effects of excipients found in the metabolites of the main components of herbal medicine, in vivo, to predict and discover the processing mechanisms of herbal medicine.

[Determination of main active components in crude and processed Corydalis Rhizoma samples from different habitats].

OBJECTIVE: To compare the content of water, ethanol soluble extracts and tetrahydropalmatine in crude and processed Corydalis Rhizoma samples from different habitats. METHODS: Corydalis Rhizoma was processed according to the optimum processing of the Chinese Pharmacopoeia (2010 edition), and then, the difference of the content of water,ethanol soluble extracts and tetrahydropalmatine in crude and processed Corydalis Rhizoma samples were analyzed and compared. RESULTS: From 14 different batches of Corydalis Rhizoma studies, the content of water, ethanol soluble extracts and tetrahydropalmatine in crude Corydalis Rhizoma was 12.8%-14.8%, 16.5%-19.6% and 0.043%-0.075%, respectively; As for Corydalis Rhizoma after processing with vinegar,the content of water, ethanol soluble extracts and tetrahydropalmatine was 7.58%-11.7%, 17.8%-23.5% and 0.046%-0.079%, respectively. CONCLUSION: The content of water, ethanol soluble extracts and tetrahydropalmatine varies slightly in the same type of samples from different habitats,which might be due to the difference in soil and climate in each habitat.