Application and problems analysis of traditional Chinese medicine volatile oil preparation technology based on ionic liquids / 中国中药杂志

Ionic liquids(ILs) are salts composed entirely of anions and cations in a liquid state at or near room temperature, which have a variety of good physicochemical properties such as low volatility and high stability. This paper mainly reviewed the research overview of ILs in the application of traditional Chinese medicine(TCM) volatile oil preparation technology. Firstly, it briefly introduced the application of TCM volatile oil preparation technology and composition classification and physicochemical properties of ILs, and then summarized the application of ILs in the extraction, separation, analysis, and preparation of TCM volatile oil. Finally, the problems and challenges of ILs in the application of TCM volatile oil were explained, and the application of ILs in TCM volatile oil in the future was prospected.

Vortex-assisted ionic liquid microextraction coupled to flame atomic absorption spectrometry for determination of trace levels of cadmium in real samples

A simple and rapid vortex assisted ionic liquid based liquid-liquid microextraction technique [VALLME] was proposed for preconcentration of trace levels of cadmium. According to this method, the extraction solvent was dispersed into the aqueous samples by the assistance of vortex agitator. Cadmium preconcentration was mediated by chelation with the 8-hydroxyquinoline; [oxine] reagent and an IL, 1-octyl-3-methylimidazolium hexafluorophosphate [[Omim][PF[6]] was chosen as the extraction solvent to extract the hydrophobic complex. Several variables such as sample pH, concentration of oxine, volume of [Omim][PF[6]] and extraction time were investigated in details and optimum conditions were selected. Under the optimum conditions, the limit of detection [LOD] was 2.9 microg L[-1] for Cd [] and relative standard deviation [RSD%] for five replicate determinations of 125 microg L[-1] was 4.1%. The method was successfully applied to the determination of cadmium in tap water, apple and rice samples

Characterization of aqueous silver nitrate solutions for leakage tests

OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silver nitrate salt (Merck, Synth or Cennabras) at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h) and concentrations (1, 5, 25, 50 percent) of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25 percent or 50 percent AgNO3 solution and the primary teeth in 5 percent or 50 percent AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5 percent). RESULTS: The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9). Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm). In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000). CONCLUSIONS: Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5 percent concentration, the solutions were capable of indicating loss of marginal seal in the composite restorations; the 3-step conventional adhesive system had better performance regarding microleakage in enamel on primary and permanent teeth.

On the electrodeposition of reactive metals from ionic liquids

In this paper we show that ionic liquids can be used for the electrodeposition of highly reactive elements, which can not be obtained from aqueous solutions, such as aluminium, magnesium and lithium as well as of refractory metals such as tantalum and titanium. The development of ionic liquids, especially air and water stable ones, has opened the door for the electrodeposition of reactive elements which in the past were only accessible using high temperature molten salts or, in part, organic solvents. Due to their high stability, ionic liquids can be regarded as the missing link to high temperature molten salts. Currently, ionic liquids can not yet replace molten salts in the electrowinning of reactive and refractory metals. Nevertheless, they can be employed efficiently for the coating of other metals with thin layers of tantalum, aluminum and presumably many other ones at reasonable temperatures. From a practical point of view, molten salts are hardly suited for the coating of sensitive materials like NiTi shape memory alloy with other metals since the electrolysis process is performed usually at temperatures above 400 C. With ionic liquids a technical electroplating process might be performed at moderate or even at room temperature