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- Author or Editor: Q. Yang x
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Summary
A simple and rapid HPLC method using a photodiode array (PDA) detector for the analysis of 3-hydroxycarboplatin and its related complex has been established for the first time. Separation of 3-hydroxycarboplatin and 3-hydroxy-1,1-cyclobutanedicarboxylic acid (3-HO-cbdca) was carried out on a Phenomenex ODS3 column using an aqueous solution containing 50 mM ammonium acetate and 5 mM sodium 1-octanesulfonate as the mobile phase. The flow rate was 0.8 mL min−1, the column temperature was 40°C, and the detection wavelength was 230 nm for 3-hydroxycarboplatin and 220 nm for 3-HO-cbdca. Different analytical performance parameters such as precision, accuracy, linearity, stability of the solution, specificity, limit of detection (LOD), limit of quantification (LOQ), and system suitability were determined using the Empower 2 software. The calibration curve of standard 3-hydroxycarboplatin showed good linearity (r = 0.9995) within the range 0.5–1.4 mg mL−1. The method was accurate and precise, with an average accuracy of 100.4% (RSD = 1.53%, n = 9), and the results of the system suitability test showed symmetrical peaks, good resolution (R s), and repeatability. It can be applied to the quality control of 3-hydroxycarboplatin.
Seven compounds, including two flavanones, dihydrokaempferol (1) and naringenin (2), and five terpenoids, boscartol A (3), 3,7-dioxo-tirucalla-8,24-dien-21-oic acid (4), 3α-acetoxyl-7-oxo-tirucalla-8,24-dien-21-oic acid (5), 11-keto-β-boswellic acid (6), and acetyl-11-keto-boswellic acid (7), have been purified by high-speed counter-current chromatography (HSCCC) from olibanum. For the separation, from 250 mg of the crude extract, 3.1 mg of 1 (95.2% purity), 2.7 mg of 2 (96.1% purity), 9.1 mg of 3 (96.7% purity), 4.5 mg of 4 (95.3% purity), 5.4 mg of 5 (96.3% purity), 48.1 mg of 6 (96.8% purity), and 45.5 mg of 7 (98.1% purity) were obtained by HSCCC with petroleum ether–ethyl acetate–methanol–water (1:0.8:1.1:0.6, v/v). The structures of these seven compounds were elucidated by a combination of electrospray ionization mass spectrometry (ESI–MS) and extensive nuclear magnetic resonance (NMR) spectroscopic.
Traditional Chinese medicine (TCM) has been widely used in many countries for thousands of years and played an indispensable role in the prevention and treatment of diseases, especially the complicated and chronic ones. However, the application of TCM in diseases is still not fully recognized by people around the world, the main reason is that Chinese herb is a very complex mixture containing hundreds of different components. Thus, it is essential to make quality control and evaluation of TCM. A new quality evaluation method, quantitative analysis of multi-components by single marker (QAMS), was developed to the quality control of alkaloids in TCM, a case study on Radix aconiti lateralis, named Fuzi in Chinese. Six alkaloids, including aconitine, hypaconitine, mesaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, were selected as main components to evaluate the quality of Radix aconiti lateralis. The feasibility and accuracy of QAMS were checked by the external standard method, and various high-performance liquid chromatographic instruments and chromatographic conditions were investigated to verify its applicability. Using aconitine as the internal reference substance and the content of aconitine was calculated according to relative correction factors by high-performance liquid chromatography. The present results showed that there was no significant difference observed between the QAMS method and the external standard method with the relative average deviations less than 3.0%, and QAMS is an effective way to control the quality of herbal medicines and seems to be a convenient and accurate approach to analyze multi-composition when reference substances are unavailable.
Abstract
External-beam PIXE was used for the non-destructive analysis of early glasses unearthed from the tombs of Warring States (475–221BC) and Han Dynasty (BC 206–AD 220) in south China. It was found that these glasses were basically attributed to PbO—BaO—SiO2 system and K2O—SiO2 system. The results from the cluster analysis showed that some glasses had exactly the same recipe. The source of the K2O flux and the correlation between PbO and BaO are discussed. Some archeological information is revealed.
Abstract
Although Ir anomaly has been discovered in a number of C/T boundaries in the world, no positive results of this anomaly in Permian/Triassic (P/Tr) boundary were given. There are many well-developed P/T sections in South China. One of representative sections is located at the Baoqing quarry, Meishan Town, Changxin County, Zhejiang Province. Ir, Os, Re, Au, Pt, Cu and Mo were determined by the radiochemical procedure developed in our laboratory. (1) Besides those accessible by INAA. The results reveal that the refractory siderophile and other chalcophile elements have certain enrichment near and at the boundary layer. However, the Ir/Au and other element abundance ratios fail to accord with the extraterrestrial values. The nature of the boundary event was discussed in terms of elemental geochemistry.
Abstract
The concentrations of 14 elements, including Ir, Au, Co, Cr, Fe, Sr, Rb, K, Ta, Zn, Sb, Ba, Sc and Se, in the Wuxi fallen ice were determined by neutron activation analysis. The experimental results show that the relative concentration ratios of Ir/Co, Ir/Cr and Ir/Sc etc. in the ice water (0.0069, 0.00024 and 0.11, respectively) are quite close to those of Type C1 chondrite (0.0102, 0.00021 and 0.092, respectively), which implies that the fallen ice might be a piece of extraterrestrial substance.
Abstract
The exfoliated poly(vinyl chloride) (PVC)/montmorillonite (MMT) nanocomposites were synthesized by in situ intercalated polymerization of vinyl chloride (VC) in the presence of organic-intercalated montmorillonite (OMMT). Their structures and thermal properties were characterized. The results showed that layered silicates are well exfoliated and uniformly distributed in PVC matrix during in situ intercalated polymerization of VC in the presence of OMMT. The glass transition temperatures of PVC phases in the PVC/MMT nanocomposites are all lower than that of pristine PVC due to the incorporation of the exfoliated silicate layers in PVC matrix. The 5% mass loss temperature (T 5%), the dehydrochlorination temperature (T max1) of the PVC matrix decreased due to the free and interlayer water in MMT, the low thermal stability, and the enhanced dehydrochlorination of the PVC matrix by alkyl ammonium pre-treated MMT. However, the thermal decomposition temperature of the dehydrochlorinated PVC (T max2) and char at 600C are slightly increased in the presence of silicate layers.
Abstract
The extraction of europium to a W/O microemulsion with an anionic surfactant was studied. In the sodium oleate (NaOL)/pentanol/heptane/NaCl system, the influence of aqueous-microemulsion ratio, concentration of NaOL, extraction temperature, concentration of cosurfactant, pH and salting-out agent on the extraction yield were investigated. Europium was probably extracted into the microemulsion phase in the form of Eu(OL)2Cl, and the extraction yield (E%) was above 99% when R = 8. The enthalpy and entropy of Eu(III) extraction were calculated to be −12.18 kJ/mol and −61.41 J/(mol K), respectively. The back-extraction is conducted by hydrochloric acid (0.8 mol/L), which provided better back-extraction yields (95.15%).
The hypothesis of niche differentiation with respect to resources is considered to be one of the most influential explanations for the maintenance of species diversity. The hypothesis has been examined extensively by testing its prediction of species-habitat association, which posits that the spatial distribution of species is highly correlated with environmental variables. However, we argue that widespread evidence of the species-habitat association lacks adequate rigor to justify the niche differentiation hypothesis. In this study, we tested whether and to what extent the observed species-habitat association could be caused by ecological processes other than niche differentiation, in a 20-ha subtropical forest plot. The niche differentiation hypothesis was evaluated by testing the species-habitat association and performing a cross-evaluation of the habitat-diversity expectation, which posits that a strong positive correlation exists between species diversity and habitat complexity. Failure to support the habitat-diversity expectation would at a minimum indicate that the niche differentiation hypothesis might not be the main underlying process of species distribution, despite prevalence of the species-habitat association in the same plot. Our analysis revealed that distributions of most species (86.11%) in the plot were significantly associated with at least one of eight topographical and soil nutrient variables. However, there was almost no significant positive correlation between species diversity and habitat complexity at various spatial scales in the same plot. The results indicate that additional caution is warranted when interpreting the species-habitat association from the niche differentiation perspective. A significant species-habitat association indicates only a species’ habitat preference. The association may reveal nothing about interspecific differences in habitat preference, which is a requirement of the niche differentiation hypothesis.
