用超临界流体萃取和固相萃取分析水中酚类污染物

使用自制的超临界流体萃取仪，比较了从Ｃｈｒｏｍｏｓｏｒｂ，Ｐｏｒａｐａｒｋ和ＧＤＸ系列的８种吸附剂上萃取苯酚，邻硝基酚，邻氯酚，对氯酚，对二甲酚，２，４－二氯酚和２，４，６－三氯酚的回收率。并用萃取回收率比较高的ＧＤＸ－３０１富集１Ｌ酸性水样中１０＾－７ｇ／ｍＬ级的以上各酚，然后用超临界ＣＯ２脱附，回收率从３２．５％到９２．９％，同时还对超临界ＣＯ２脱附ＧＤＸ－３０１上各酚的操作条件进行了优化，并     

气相色谱法分离和测定环境空气中的丙烯酸乙酯和甲基丙烯酸甲酯

用活性炭吸附环境空气中的丙烯酸乙酯和甲基丙烯酸甲酯,经二硫化碳妥吸后用气相色谱法测定在填充２．５％ＤＮＰ＋２．５％Ｂｅｎｔｏｎｅ３４／ＣｈｒｏｍｏｓｏｒｂＷ ＨＰ ＤＭＣＳ的玻璃色谱柱上,丙烯酸乙酯与甲基丙烯酸甲酯及干扰物之间能较好地分离。方法的回收率：丙烯酸乙酯为８６．４％－１０３．０％,甲基丙烯酸甲酯为８６．３％－１０１．２％,变异系数：丙烯酸乙酯为４．１％－４．４％,甲基丙烯酸甲酯为４．４％     

几种生物碱基的反相高效液相色谱分离及人尿中尿嘧啶和腺嘌呤的…

本文报道在ＳｐｈｅｒｉｓｏｒｂＣ１８柱上，以Ｈ３ＰＯ４－ＫＨ２ＰＯ４溶液作流动相（ｐＨ４．０），同时分离和测定胞嘧啶，尿嘧啶，腺嘌呤和黄嘌呤５种生物碱基，用于人尿分析，标准加入回收率在９２．５～１０５．５％之间。     

经由胂叶立德立体有择合成仿保幼激素──增丝素（ZR－512）及其（2Z，4E）－异构体

３－甲基－２－丁烯酸乙酯４经ＳｅＯ２反式氧化、还原、溴化得到关键中间体４－溴－３－甲基－（２Ｅ）－丁烯酸乙酯７．７与三苯基胂反应生成季８．二氢香茅醛与８在Ｋ＿２ＣＯ＿３－乙醇－微量水的存在下反应，得到（２Ｅ，４Ｅ）－３，７，１１－三甲基－２，４－十二碳二烯酸乙酯１ａ及其（２Ｚ，４Ｅ）－异构体１ｂ，产率７４％。该反应具有（４Ｅ）－立体选择性，同时Ｃ－２双键发生部分构型转化。     

经由胂叶立德立体有择合成仿保幼激素──增丝素（ZR—512）…

３－甲基－２－丁烯酸乙酯４经ＳｅＯ２反式氧化，还原，溴化得到关键中间体４－溴－３－甲基－（２Ｅ）－丁烯酸乙酯７．７与三苯基胂反应生成季Ｓｅｎｇ盐８。二氢香茅醛与８在Ｋ２ＣＯ３－乙醇－微量水的存在下反应，得到（２Ｅ，４Ｅ）－３，７，１１－三甲基－２，４－十二碳二烯酸乙酯１ａ及其（２Ｚ，４Ｅ）－异构体１ｂ，产率７４％，该反应具有（４Ｅ）－立体选择性，同时Ｃ－２双键发生部分构型转化。     

单柱离子色谱法测定痕量草酸根离子

本文采用单柱离子色谱系统测定了Ｃ２Ｏ＾２－４，以１．３ｍｍｏｌ／Ｌ葡萄糖酸钠／１．３ｍｍｏｌ／Ｌ硼砂为淋洗液测定Ｃ２Ｏ＾２－４，８常见阴离子Ｃｌ＾－，ＮＯ＾－３，ＨＰＯ＾２－４，ＳＯ＾２－４不干扰测定，Ｃ２Ｏ＾２－４的检出限为０．５７ｍｇ／Ｌ，相对标准偏差为１．０７％，工作曲线的线性范围为０．５７－５００ｍｇ／Ｌ，应用本方法测定了加Ｃ２Ｏ＾２－４的自来水样，Ｃ２Ｏ＾２－４的回收率为９９．５２％。     

氢化物发生—冷阱捕获—色谱分离—原子吸收法测定天然水中坤的形态

研究建立了氢化物发生－冷阱捕获－色谱分离－原子吸收方法测定天然水中四种主要砷形态，测试系统自行组装，色谱柱填料采用ＣｈｒｏｍｏｓｏｒｂＧＡＷ－ＤＭＣＳ（粒径０．３～０．４５ｍｍ），其上涂布３％ＯＶ－１０１。方法的检出限以砷计分别为：Ａｓ（Ｖ）０．５１ｎｇ，Ａｓ（Ⅲ）０．４３ｎｇ，ＭＭＡ０．３８ｎｇ，ＤＭＡ０．６７ｎｇ；１２ｎｇ砷标准偏差为Ａｓ（Ⅴ）４．２１％，Ａｓ（Ⅱ）３．５６％，ＭＭＡ３．２３％     

四元体系CsCl—PrCl3—13%HCl—H2O（25℃）和CsCl—PrCl3—42%H…

测定了四元体系ＣｓＣｌ－ＰｒＣｌ３－１３％ＨＣｌ－Ｈ２Ｏ（２５℃）和ＣｓＣｌ－ＰｒＣｌ３－４２％ＨＡｃ－Ｈ２Ｏ（３０℃）的稳定平衡态的溶液数据，绘制了相应的溶度图，两个体系的皆中有４种固相，ＣｓＣｌ，ＰｒＣｌ３．６Ｈ２Ｏ２种原始盐和ＣｓＣｌ．ＰｒＣｌ３．６Ｈ２Ｏ，３ＣｓＣｌ．ＰｒＣｌ３．７Ｈ２Ｏ２种复盐，证实了文献中对Ｍｅｙｅｒ反应１机理的解释，并对新相进行了热分析，Ｘ射线粉末衍射及偏光显微镜测定     

海水中甲基,丁基锡的形态分析

对海水中甲基、丁基锡的氢化反应与捕集、色谱分离及其原子化等进行了条件实验和最佳化。采用１５ｃｍＣｈｒｏｍｏｓｏｒｂＧＡＷ—ＤＭＣＳ载体和ＯＶ—３固定液，色谱分离锡的无机、一甲、二甲、三甲、一丁、二丁、三丁基化合物的保留时间分别为４０、１００、１２５、１３９、１６０、１９１、２２８ｓ；在０．２００ｄｍ３水样中直接测定海水中各形态锡的检出限分别为１．９、１．６、１．８、３．０、１．３、１．４、２２．４、ｎｇＳｎ·ｄｍ－３；其相应的测量精密度在１０％左右。     

一系列烷基对二烷氧基苯在不同硝化体系中反应的研究

２－烷基－１，４－二甲氧基苯１ａ－ｄ（烷基为ＣＨ３，ＣＨ３ＣＨ２，ＰｈＣＨ２，（ＣＨ３）３Ｃ）分别在ＨＮＯ３－ＨＯＡｃ和ＮＨ４ＮＯ３－ＨＯＡｃ中反应后生成占绝对优势的硝化产物２－烷基－５－硝基－１，４－二甲氧基苯４ａ－ｄ，而２－烷基－５－叔丁基－１，４－二甲氧基苯２ａ－ｄ及２，５－二叔丁基－１，４－二苄氧基苯３在上述二种硝化体系中的反应在很大程度上取决于所用的硝化体系的性质及反应物的结构。对上述反     

Supercritical fluid extraction of 2,3,7,8-tetrachlorodibenzo-p-dioxin from sediment samples

Supercritical fluid extraction (SFE) is a promising technique for the extraction of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) from environmental matrices such as contaminated sediments. The ability of SFE to solubilize many organic contaminants is well documented in industrial processes but its analytical applications were exploited just recently. In this study supercritical carbon dioxide and nitrous oxide and their mixtures with 2% methanol were used to extract 2,3,7,8-TCDD from aquatic sediments. An attractive feature of this process is that the carbon dioxide, being a virtually inert fluid, leaves no solvent residue on the processed sediment. Almost 100% of the 2,3,7,8-TCDD can be extracted from a sediment spiked with 200 μg/kg 2,3,7,8-TCDD in 30 minutes by using supercritical carbon dioxide + 2% methanol. Cleanup procedure is compared with the Soxhlet extraction procedure currently used as a standard method for extracting dioxins from sediment samples.     

Multi-layer cartridges filled with multi-walled carbon nanotubes for the determination of volatile organic compounds in indoor air.

A kind of new multi-layer adsorbent including Tenax TA/multi-walled carbon nanotubes (MWCNTs)/Carboxen 564 was developed for collecting volatile organic compounds. The adsorption and desorption efficiencies of 11 kinds of adsorbents (including Activated charcoal, Tenax TA, Carboxen 564, Chromosorb 101, Chromosorb 102, Chromosorb 103, Chromosorb 105, Porapak Q, GDX 301, XAD-2, and MWCNTs) were compared. By combining the advantages of Tenax TA, MWCNTs, and Carboxen 564, new type of multi-layer adsorbents was developed. The adsorption and desorption efficiency, the sampling reproducibility, and the effect of water were improved using multi-layer adsorbents, Tenax TA/MWCNTs/Carboxen 564. New multi-layer adsorbents were successfully applied to the determination of volatile organic compounds (VOCs) in ambient air.     

Comparison of supercritical fluid and ultrasound-assisted extraction of carotenoids and chlorophyll a from Dunaliella salina

In the work described here the extraction processes of carotenoids and chlorophylls were analysed using two extraction techniques, namely ultrasound-assisted extraction and supercritical fluid extraction, and the results are compared. The solvents used for the ultrasound-assisted extraction were N,N′-dimethylformamide and methanol and for the supercritical fluid extraction, carbon dioxide. The raw material studied was Dunaliella salina, a microalgae characterized by the high levels of carotenoids present in its cellular structure. The results indicate that the supercritical fluid extraction process is comparable to the ultrasound-assisted extraction when methanol is used as solvent. In addition, the supercritical extraction process is more selective for the recovery of carotenoids than the conventional technique since it leads to higher values for the ratio carotenoids/chlorophylls. Finally, the effects of pressure and temperature on the extraction yields of the supercritical fluid extraction process were studied.     

Supercritical fluid extraction and liquid chromatography-electrospray mass analysis of vinblastine from Catharanthus roseus

Supercritical fluid extraction using carbon dioxide modified with methanol, methanol-diethylamine, or methanol-triethylamine was used to extract vinblastine from the aerial portions of Catharanthus roseus. An HPLC-electrospray ionization (ESI)/MS analysis method was also developed to quantify the alkaloids in these extracts. Of the supercritical solvents evaluated, carbon dioxide-methanol-triethylamine (80 : 18 : 2) at 80 degrees C and 34.0 MPa greatly improved the supercritical fluid extraction (SFE) yield of vinblastine by as much as 76.4% over methanol extraction, while the other solvent conditions extracted the compound at yields less than 25% that of a methanol extraction. These results were confirmed by the robust HPLC-ESI/MS analytical method developed in this study.     

Effect of temperature,collection mode,and modifier on the supercritical CO2 extraction of dicofol residues from fish samples

Toxicity evaluation of Dicofol to Astyanax bimaculatus schubarti, a characteristic fish species living in tropical rivers and lakes was carried out through LC₅₀ – 96 Hours. These experiments were performed under laboratory controlled conditions with atmospheric air flow and dilution water at 25°C in the static mode, supercritical fluid extraction (SFE) with pure CO₂ and CO₂ modified with hexane and methanol were used at 50, 70, 80, and 100°C and 300 atm. Several collection modes were studied to extract Dicofol from fish samples. The extraction efficiencies were directly comparedd with those obtained after 8 h of Soxhlet extraction using the same clean-up with Florisil and analysis by HRGC/ECD and HRGC/MS as a confirmatory analytical technique. The SFE recoveries at temperatures lower than 80°C were typically lower than soxhlet recoveries; however a temperature increase enhanced the efficiency of SFE. The results showed that under certain conditions, supercritical fluid gave higher extractio power (extracted 11 % more pesticide), shorter extraction time, and lower solvent consumption than Soxhlet, thus affording an excellent alternative to the conventional method for extracting Dicofol from fish sample.     

Determination of Microcystins in Cyanobacteria by Supercritical Fluid Extraction and Liquid Chromatography‐Tandem Mass Spectrometry

Abstract

A method for the detection of microcystins (microcystin LR, RR, and YR) in cyanobacteria by supercritical fluid extraction (SFE) and liquid chromatography‐mass spectrometry (LC/MS) has been developed. Supercritical fluids for the analytical extraction of nonvolatile, higher molecular weight compound, and microcystins from cyanobacteria were investigated. The microcystins included in this study are sparsely soluble in neat supercritical fluid CO₂. However, the microcystins was successfully extracted with a ternary mixture (90% CO₂, 9.5% methanol, 0.5% water) at 40°C and 250 atm. The polar carbon dioxide‐aqueous methanol fluid system gave high extraction efficiency for the extraction of the polar microcystins from cyanobacteria. The microcystins were determined by liquid chromatography‐tandem mass spectrometry (LC/MS/MS).     

Evaluation of dithiocarbamates and beta-diketones as chelating agents in supercritical fluid extraction of Cd, Pb, and Hg from solid samples

The use of four dithiocarbamates and three fluorinated β-diketones as potential chelating agents for three transition metal ions (Cd²⁺, Pb²⁺, and Hg²⁺) extracted from spiked sand and filter paper samples by supercritical fluid extraction (SFE) was investigated. The extractions were performed at 45°C and 250 atm for spiked sand samples and at 60°C and 200 atm for filter paper samples using supercritical carbon dioxide modified with 5% methanol. At 250 atm and using carbon dioxide modified with 5% methanol, the recoveries of Cd²⁺, Pb²⁺, and Hg²⁺ ions from spiked sand samples were 95% with lithium bis(trifluoroethyl)dithiocarbamate (LiFDDC) as the chelating agent; they ranged from 83–97% with diethylammonium diethyldithiocarbamate and from 87–97% with sodium di-ethyldithiocarbamate as chelating agents, and from 68–96% with trifluoracetylacetone, hexafluoroacetylacetone, and thenoylfluoroacetone as chelating agents. Ammonium pyrrolidinedithiocarbamate was not effective in the chelation SFE of Cd²⁺, Pb²⁺, and Hg²⁺ ions from either spiked sand or spiked filter paper samples under the extraction conditions used. Supercritical carbon dioxide alone gave consistently lower analyte recoveries than supercritical carbon dioxide modified with 5% methanol. The results suggest that the solubility of the metal chelate in the supercritical fluid plays a more important role than the solubility of the chelating agent in the supercritical fluid, as long as sufficient chelating agent is present in the fluid phase. Fluorination of the chelating agent, as in the case of LiFDDC, increases the solubility of the metal chelate, and subsequently enhances the extraction efficiency for the metal ions.     

Extraction of ferulic acid from Angelica sinensis with supercritical CO2

Extraction of pharmacologically active ingredient of ferulic acid from the root of Angelica sinensis with supercritical CO2 was investigated. The experimental results show that the extract yields were 0.87-4.06% at temperatures from 45 to 65 degrees Celsius and pressures from 30 to 50 MPa, and the maximum content of ferulic aicd in the extracts was about 0.35-0.37%, which is lower than that of 0.61-0.85% by conventional percolation methods. Ethanol was used as co-solvent in different ratios to raw materials in order to increase the content of ferulic acid in the extracts. The experimental results show that both the extract yields and the content of ferulic acid in the extracts increase greatly compared with pure CO2 extraction. When the ratio of ethanol to the raw material was 1.6, the content of ferulic acid in the extracts was 0.91-1.27%, indicating that supercritical fluid extraction (SFE) with CO2 in the presence of suitable co-solvent is superior to percolation in extracting polar ferulic acid from Angelica sinensis.     

Extraction of atrazine and its metabolites using supercritical fluids and enhanced-fluidity liquids

Supercritical fluid and enhanced-fluidity liquid extractions are performed on spiked sediment samples containing atrazine (ATRA) and five of its metabolites including desisopropyldesethylatrazine, desethylhydroxyatrazine (DEHA), desisopropylatrazine, desethylatrazine, and hydroxyatrazine (HA). The hydroxylated metabolites are of particular interest because of their increased water solubility and the fact that their high polarity makes them difficult to analyze. Soxhlet extractions using methanol are conducted for the purpose of comparison. Results of the extractions show that the hydroxy-containing metabolites of ATRA are not effectively extracted with supercritical CO2 alone. The solvating or desorbing power of carbon dioxide appears too low to extract HA and DEHA. The extraction recoveries of the hydroxylated metabolites increase when enhanced-fluidity liquid mixtures of methanol/CO2 are used, and these rates increase with the methanol concentration. Enhanced-fluidity ternary liquid mixtures of H2O/methanol/CO2 yield the best recoveries for these compounds. ATRA recoveries are equally effective when using supercritical CO2 or enhanced-fluidity mixtures. The other nonhydroxy-containing metabolites require the increased solvent strength of either large percentages of methanol in CO2 or ternary mixtures of H2O, methanol, and CO2 for high recoveries. Recoveries with enhanced-fluidity liquid ternary mixtures are better than the recoveries from Soxhlet for all the compounds in the study.     

Study on a New Method of Extraction of Metal Ions from Solid Matrices by Supercritical Fluid

TOdate.mostofthepublishedSFEworkshavefocusedonorganiccompound',andsomereportshaverelatedtoSFEofmetalions2.DirectextractionofmetalionsbysupercriticalCO,ishighlyinefficient.OneapproachofextractingmetalionsbysupercriticalCO=issuggestedtoconvertthechargedmetalionsintoneutralmetalcomplexesbyusingchelatingagentinthesupercriticalCO,.Avarietyoforganicchelatingagentssuchasthiocarbamate,D-diketones,andcrownetherhavebeenusedinSFEofmetalions3.8Hydroxyquinolinecontainsdoublecoordinationatoms(N,O-),…