The samples were subjected to microwave digestion using different amounts of citric acid(HNO3-HC1-HF)system.Using 45Sc,103Rh and 209Bi as internal standards,ICP-MS was used to simultaneously determine Cr,Co,Ni,Cu,Zn,Pb,and Cd in soil samples.The experimental results show that the correlation coefficients of the standard curves for each element are all above 0.9999,and the detection limit of the method is 0.004～0.434 μg·g-1,with a recovery rate of 90.4％～108.9％and a precision of 0.8％～8.4％,all results are within the reference range.After accuracy and precision analysis,acid system Ⅰ is slightly better than system Ⅱ.Both systems can completely dissolve the metal elements to be tested,with basically no volatilization loss,and have good reliability.This method has simple pre-processing,short time consumption,high sensitivity,and high accuracy,providing a real and effective detection basis for the determination of heavy metal elements in soil.It is suitable for the simultaneous determination of multiple metal elements in ecological geochemistry and the third national soil survey samples.
Quinoline is an important nitrogen-containing heterocyclic compound,which is widely found in nature and active drug molecules.Quinoline is widely used in organic synthesis and medicinal chemistry because of its special chemical property and many chemical reactions.At present,the synthesis and application of quinolines have been reported extensively.In this paper,the synthetic methods of quinolines and their applications in organic synthesis and medicine are reviewed,it is expected to provide references for the development of new quinoline active drug molecules.
In order to improve the recovery of low permeability reservoirs,in this paper,polyethylene glycol modified silica nanoparticles were used as additives to improve the foam stability,four different surface modification amounts of silica nanoparticles(i.e.,polyethylene glycol films)were synthesized by sol-gel method,and the nanoparticles were characterized,and properties such as zero charge point and chemical composition were characterized.Nanofluids were obtained by mixing surfactant solution and nanoparticles.The nanoparticles,in synergy with the surfactant,structurally strengthened the bubbles to increase their half-life and durability.The bubble stability reaches a maximum when the surfactant concentration was higher than the CMC.The lower the nanoparticle concentration in the nanofluid,the smaller the polymerization particle size.The amount of polyethylene glycol can prevent or promote the aggregation of nanoparticles,and the smaller the particle size,the better the stability of the foam.Foams generated with α-olefin sulfonate surfactants and modified nanoparticles are more stable than those with surfactants only.
OBJECTIVE To optimize the extraction process of total polysaccharides saponins,phenols and flavonoids from rhizome Polygonati rhizoma by response surface method(RSM).METHODS The components above were extracted by ultrasonic extraction and were isolated in the way of gradient solvent extraction by using benzene,ethyl acetate,n-butanol alcohol as solvents.Optimized by the design of Design-Expert based on the theory of Central Composition.The contents were determined by UV-VIS spectrophotometry.RESULTS Through single factor experiment screened out the extraction temperature range of the active components was 31～54℃,the ratio of solid-liquid was 1∶5～1∶15,the ultrasonic frequency range was 24.00～32.00kHz,and the ultrasonic duration was 10～50 mins.The solid-liquid ratio and ultrasonic frequency with large influencing factors were selected to conduct the orthogonal experiment with two factors and three levels.Combined with extraction rates of Polygonati rhizoma polysaccharides,saponins,flavonoids and polyphenols,the extraction conditions were determined as ultrasonic frequency 24.80 kHz and solid-liquid ratio 1∶10.62.CONCLUSION The results of RSM were significantly higher than those of single factor screening and extraction before optimization.The results showed that the established experimental model was stable and reliable,and the optimized results could provide theoretical support for the rational development and utilization of raw and processed Polygonati rhizoma,and also provide guidance for the optimization of extraction technology of other Chinese medicinal materials.
The flavonoids of Elephantopus scaber were extracted with methanol,purified by macroporous resin and separated by Waters BEH C18 chromatographic column.Formic acid-aqueous solution(1%)and formic acid-acetonitrile solution(1%)were used as mobile phases with the flow rate of 0.2mL·min-1,the column temperature was 30℃,injection volume was 1μL.UPLC/MS/MS electrospray to ionization,multi-reaction monitoring mode to detection,retention time and subion ratio to qualitative,external standard method to quantity were performed.The five flavonoids ingredients of Elephantopus scaber could be separated and analyzed under the chromatographic conditions.Experiment results showed that the average content of luteolin from Elephantopus scaber was 8.75g·kg-1,the average content of kaempferol from Elephantopus scaber was 0.86g·kg-1,the average content of catechin from Elephantopus scaber was 4.29g·kg-1,the average content of apigenin from Elephantopus scaber was 2.43g·kg-1,the average content of rutin from Elephantopus scaber was 10.71g·kg-1.The flavonoids of Elephantopus scaber were rich type and high content.The study provides the theoretical foundation for the flavonoids content measure and the further development of Elephantopus scaber.
