液膜萃取技术在环境样品前处理中的应用

膜分离技术是利用膜对混合物中各组分的选择渗透性能的差异来实现分离、提纯和浓缩的新型分离技术。近年来,随着人们环保意识的加强,环境中污染物的监测逐渐被重视。因环境样品基体的复杂性,在分析测定前必须进行净化处理。将膜分离技术与液液萃取技术相结合的液膜萃取技术因其     

气相色谱-电子捕获检测器法检测水中氟乐灵

建立了气相色谱仪检测水中氟乐灵的方法. 分别采用液液和固相两种萃取浓缩的方式进行样品预处理,两种方法均能满足要求. 液液萃取操作简单,节约时间. 固相萃取能实现自动化处理,节省劳力. 浓缩后使用HP-5色谱柱分离,电子捕获检测器进行测定. 试验结果表明,当水中氟乐灵的质量浓度在0.05~1.0 μg/L范围内,其工作曲线回归方程的相关系数高于0.999,方法检出限(3 S/N)为0.02 μg/L. 在两种不同浓度水平条件下对方法的回收率和精密度进行了试验,其回收率在84.0%~98.0%之间,相对标准偏差在3.0%~5.8%之间.     

适用于液膜分离的磺化液体聚丁二烯型聚合物表面活性剂

液膜技术作为一种高效、快速的分离工艺已应用于工业废水处理,分离和浓缩金属离子和某些有机化合物,它的成功应用有赖于性能优良的表面活性剂的研究和开发。聚合物表面活性剂可增加液膜的强度,可提高所得乳液的稳定性,受到     

液液萃取/气相色谱－质谱法测定氟［18F］脱氧葡糖注射液塑料生产组件浸提液中16种邻苯二甲酸酯类增塑剂

建立了基于液液萃取（LLE）/气相色谱－质谱（GC－MS）检测氟［18F］脱氧葡糖注射液塑料生产组件浸提液中16种邻苯二甲酸酯类（PAEs）增塑剂的方法。根据生产工艺,采用含5%乙醇、5%乙腈的混合溶液作为模拟溶剂,在40 ℃条件下进行模拟浸提。采用Thermo TG－5 SIL MS色谱柱分离,选择离子扫描模式（SIM）进行分析。通过对仪器条件与萃取条件进行优化,确定最佳前处理方法和仪器条件。在优化实验条件下,16种PAEs在50～500 ng/mL范围内与峰面积呈良好的线性关系,相关系数（r）均不小于0.990 6,检出限（LOD）和定量下限（LOQ）分别为10、30 ng/mL。以二氯甲烷为萃取溶剂时,平均回收率为83.0%～114%,相对标准偏差（RSD,n = 6）为1.9%～4.2%。采用该方法对浸提液进行测定,16种PAEs均未超过分析评价阈值（AET）。该法操作简便,专属性强,可用于氟［18F］脱氧葡糖注射液塑料生产组件的相容性研究。     

固相微萃取法和液液萃取K-D浓缩法对化妆品香气的分析

分别利用固相微萃取法和液液萃取K-D浓缩法对化妆品调理水中的香气提取物进行分析比较。用这两种方法从化妆品调理水中提取、鉴定出30个化合物,从固相微萃取法提取物中鉴定出23个化合物,液液萃取K-D浓缩法提取物中鉴定出16个化合物,其中相同的化合物有9个。结果表明,两种提取方法得到的香气成分有明显差异,其香气特征成分主要集中在固相微萃取法所富集部分,因此采用固相微萃取法能够快速、高效、全面地对香气的香型进行定性分析。     

离心分离共沉淀原子吸收光谱法测定饮用水中铅和镉

对于水中铅、镉等金属离子的测定，采用火焰原子吸收光谱法测定的灵敏度比较低，必须对水样中被测离子进行浓缩或富集处理，常用的水样预处理的方法有巯基棉富集法、液液萃取法和共沉淀法，共沉淀法较其它方法具有操作简便、经济的优点。目前普遍采用自然沉降共沉淀并用虹吸上清液进行液固分离的浓缩方法，测定中常出现管壁吸附现象和液面张力使得少量沉淀浮在液面上，     

脐橙皮中黄酮类化合物与果胶的分离和提取研究

黄酮类化合物是具备主要生物活性的天然产物,果胶是人体7大营养素中膳食纤维的主要成分.实验就黄酮和果胶提取分别作L9(34)和L16(44)正交化实验.工艺条件表明,提取黄酮的较佳工艺条件是:固液比1∶30,超声处理时间55 min,处理温度50℃,浸提液浓缩得到粗黄酮.提取黄酮后的脐橙皮渣中提取果胶的较佳工艺条件是:70℃的温度,提取时间为55 min,pH=2.0,固液提取比为1∶25.     

流动注射分光光度法测定矿物浸提液中的游离氰化物

在氢氧化钠介质中游离的氰化物与苦味酸钠反应生成玫瑰红酸钠，并进行升温改善反应条件。双流路系统与单流路相比，峰形规范、光滑，能有效消除鬼峰，优化了显色条件，工作波长为５１０ｎｍ。按生产工艺要求的线性范围为４．０￣４０．０ｍｍｏｌ／Ｌ。进样频率为１３０次／ｈ。已成功地用于矿物浸提液中游离氰化物的现场分析。     

自动固相微萃取(SPME)GC-MS、GC-MS-MS法检测环境水中有机磷杀虫剂的研究

固相微萃取(solid-phasemicroextraction,SPME)是20世纪90年代发展起来的一种样品前处理技术,与传统的液-液提取、液-固提取相比,SPME更适用于提取、浓缩液态或气态的挥发性和半挥发性物质,SPME技术可将采样、萃取、浓缩和样本引入集中于一个步骤完成,尤其随着自动SPME与GC-MS等联用技术的日益完善,使SPME技术优点得到更充分的发挥。     

利用柠檬酸去除污泥中重金属的新工艺

经柠檬酸络合后采用离子交换法处理污泥中的重金属,该方法包括3个步骤:浸提过程、固液分离、浸提液的净化和循环。对影响浸提液的净化和循环步骤中的主要影响因素进行了研究。结果表明,732型阳离子交换树脂性能优异,对重金属的离子交换率接近100%;以5%HCl溶液为洗脱剂,动态逆流操作条件下,Cu、Ni和Zn的洗脱率分别达到88.85%、86.15%和88.40%;以铝片为置换剂,对重金属Pb、Cd、Cu、Ni都能得到90%以上的置换率。循环实验表明,处理后污泥中的重金属含量符合《农用污泥中污染物控制标准》(GB4284-84),柠檬酸可以实现循环使用。     

澳大利亚高盐煤中钠在热解过程中的形态变迁

通过对高钠煤进行水洗以及0.1 mol/L的HCl洗涤,并在固定床上考察了不同洗煤热解后的半焦中Na的挥发性及其形态变迁。热解后的半焦用水和0.1 mol/L的HCl逐级萃取,将热解半焦中的钠分为水溶态钠,水不溶但酸溶态钠以及酸不溶态钠。研究结果表明,实验煤中的钠大部分是以水溶态的NaCl盐形式存在,在500℃~550℃由于以羧酸盐形式存在的有机钠以钠原子的形式释放使得在该温度范围内钠的挥发性出现极大值,而酸洗煤由于在600℃以上有一部分酸不溶态的钠转化为水不溶但酸溶态的钠,使得钠的挥发性又有所增加。原煤中的可挥发钠热解后少部分在高温下会转化为水溶态的钠,而水洗煤中的钠随着热解温度的升高与SiO2反应转化为硅酸盐形式存在的酸不溶态的钠。     

Concentrations of aluminium, iron, and copper in water of some Shatskiye Lakes and specificity of their distribution among different forms of occurrence

The results of studies on the occurrence of aluminum, iron, and copper in water of Lyutsimir and Chernoe Bol’shoe Lakes belonging to the large group of Shatsk Lake system are discussed. Iron was shown to migrate mostly as suspended particles, and copper, as soluble species. The average annual fraction of suspended aluminum is about 40%. The ratio of suspended and dissolved aluminum depends not only on the concentration of suspended particles in water, but also on their nature. Anionic complexes predominate among soluble forms of the examined metals; their fractions in water of Lyutsimir and Chernoe Bol’shoe Lakes are on the average 86 and 70% (Al), 73 and 59% (Cu), and 60 and 47% (Fe). This is determined by the major contribution of humic substances to the total content of organic matter in water of both lakes and their participation in the complexation with metals. The metals compete for active centers in humic macroligands. Carbohydrates constitute the second important group of organic substances that participate in the complexation. Neutral complexes were found to consist mainly of iron compounds. Compounds with a molecular weight not exceeding 2.0 kDa predominate among anionic metal complexes.     

A method for 13C‐labeling of metabolic carbohydrates within French bean leaves (Phaseolus vulgaris L.) for decomposition studies in soils

The molecular composition of plant residues is suspected to largely govern the fate of their constitutive carbon (C) in soils. Labile compounds, such as metabolic carbohydrates, are affected differently from recalcitrant and structural compounds by soil‐C stabilisation mechanisms. Producing ¹³C‐enriched plant residues with specifically labeled fractions would help us to investigate the fate in soils of the constitutive C of these compounds. The objective of the present research was to test ¹³C pulse chase labeling as a method for specifically enriching the metabolic carbohydrate components of plant residues, i.e. soluble sugars and starch. Bean plants were exposed to a ¹³CO₂‐enriched atmosphere for 0.5, 1, 2, 3 and 21 h. The major soluble sugars were then determined on water‐soluble extracts, and starch on HCl‐hydrolysable extracts. The results show a quick differential labeling between water‐soluble and water‐insoluble compounds. For both groups, ¹³C‐labeling increased linearly with time. The difference in δ¹³C signature between water‐soluble and insoluble fractions was 7‰ after 0.5 h and 70‰ after 21 h. However, this clear isotopic contrast masked a substantial labeling variability within each fraction. By contrast, metabolic carbohydrates on the one hand (i.e. soluble sugars + starch) and other fractions (essentially cell wall components) on the other hand displayed quite homogeneous signatures within fractions, and a significant difference in labeling between fractions: δ¹³C = 414 ± 3.7‰ and 56 ± 5.5‰, respectively. Thus, the technique generates labeled plant residues displaying contrasting ¹³C‐isotopic signatures between metabolic carbohydrates and other compounds, with homogenous signatures within each group. Metabolic carbohydrates being labile compounds, our findings suggest that the technique is particularly appropriate for investigating the effect of compound lability on the long‐term storage of their constitutive C in soils. Copyright © 2009 John Wiley & Sons, Ltd.     

Determination of organic mercury species in soils by high-performance liquid chromatography with ultraviolet detection.

Reversed-phase high-performance liquid chromatography with ultraviolet detection was optimized for the simultaneous separation and quantification of nine organic mercury compounds: methyl-, ethyl-, phenyl-, methoxyethyl-, ethoxyethyl-, benzoic and tolylmercury, mersalylic acid and nitromersol. The nine compounds were successfully separated on octadecylsilane columns (200 x 3 mm i.d.) by gradient elution with a methanol-water mixture ranging from 30 to 50% v/v. The detection limits for the various compounds are in the range 7.0-95.1 micrograms dm-3. For the extraction of five organomercurials from spiked soils, eight different extraction solutions were tested to differentiate between the total content and the available/soluble fraction of the analytes. Ammonium acetate solutions (1 mol dm-3) and water proved to be suitable agents for the estimation of the available and soluble fractions of methyl-, ethyl-, benzoic, methoxyethyl- and ethoxyethylmercury. For the determination of the total content of methyl- and benzoic mercury in soils, solutions of potassium iodide (1 mol dm-3)-ascorbic acid (0.1 mol dm-3) and oxalic acid (1 mol dm-3) provided recoveries in the ranges 53-81%. None of the solutions tested is suitable for the extraction of ethyl-, methoxyethyl- and ethoxyethylmercury.     

Structure of Alkali Lignins Fractionated from Ricinus communis and Bagasse. 1. Chemical Constituents

Fractionation of alkali lignins of the soda and sulfate pulping processes of Ricinus communis and bagasse was carried out by using successive equal concentrations of the alkaline reagent. Soda lignins were soluble in organic solvents, while the sulfate ones were sparingly soluble. Thus, two fractions of the sulfate lignins, soluble and insoluble, could be obtained from acetone. The different alkali lignin fractions were subjected to elemental and functional group analyses. For both Ricinus communis and bagasse, the carbon content of the fractions of the various types of lignin is in the order: soluble sulfate > soda > insoluble sulfate, while the methoxy is in the order: soda > soluble sulfate > insoluble sulfate. The phenolic OH content, as well as OH/C₉ of soda lignins of bagasse, are lower than those of soluble sulfate lignins. For Ricinus communis, the phenolic OH content and OH/C₉ is higher for some of the fractions (first three stages of cooking) of soda lignin than the corresponding fractions of kraft (sulfate) lignin, while the reverse takes place for the other fractions. For the same type of lignin, the fractions showed changes in their carbon, methoxyl, and phenolic OH contents. The change may be regular, i.e., increase or decrease with the order of stage of cooking, or irregular. Molecular weights of the different alkali lignins which are soluble in organic solvents ranged between 750 and 840.     

Fractionation analysis of trace metals in humic substances of soils irrigated with wastewater in Central Mexico by particle induced X-ray emission

The Mezquital Valley in Central Mexico has received wastewater from Mexico City for nearly 100 years. Wastewater brings in organic matter and nutrients but also trace metals. Humic substances, the main components of organic soil matter, are responsible for retaining and regulating the mobility of trace metals in soils. In this study, humic substances were extracted from the soil and separated into distinct fractions (humic acids, fulvic acids and humins). The particle induced X-ray emission (PIXE) technique was applied to determine the metal content in bulk soil as well as in humic acids and fulvic acids not soluble in H₃PO₄. In order to assess whether the long-term input of organic matter and metals modifies the metal association with these humic substances, parcels irrigated for three time periods (5, 47 and 89 years) were selected for this study. It was observed that metals such as Zn and Cu are mainly associated with the humic acids. Fulvic acids retain mainly Cr while Pb is distributed among humic and fulvic acids. It was also observed that in general, metal retention by humic substances increases with irrigation time. Depth also affects metal association with the humic substances.     

Recovery of metals from raw materials of industrial origin

Interaction of d elements and their compounds (oxides, sulfides, carbonates, and other compounds poorly soluble in water) with organic ligands in aprotic solvents was studied. Methods for recovery of metals from nonaqueous solutions of the resulting complex compounds are suggested.     

Medical Uses for Polyelectrolyte Complexes

Polyelectrolyte complexes (PEC) are ionically bonded hydrogels. The resin is synthesized by coreacting linear, water-soluble ionic polymers of opposite electrical charge under carefully controlled conditions. The resulting material is insoluble in water, electrolytes, organic, or common solvents, but soluble in special ternary solvents. Optically clear membranes or shaped articles can be prepared by employing simple solvent casting and drying techniques upon resin dissolution. The equilibrium gel water content of typical, homogeneous complexes can be made to range from 30 to 90% by weight by changing the initial polyanion to polycation ratio. For almost any given charge ratio the water content can be varied from 30 to 90% by initial adjustment of the solvent composition. As the gel water content of a membrane is raised the dialytic, oxygen, and water transport increase. High water content membranes with and without glass reinforcement were shown to be extremely permeable materials. Because these hydrated complexes appeared to be chemically inert and could be tailored to be rich in either polyanion or polycation charged groups, their biocompatability was studied. Extraction, toxicity, tissue compatability, carcinogenicity, and blood contact studies on various polyelectrolyte complexes were carried out.     

Effect of β-cyclodextrins based nanosponges on the solubility of lipophilic pharmacological active substances (repaglinide)

Cyclodextrin based nanosponges (CD-NS) are nanostructured cross-linked polymers, usually obtained by reacting cyclodextrin with a cross-linker such as carbonyldiimidazole, organic carbonates or (±) epichlorohydrin. They have been used to increase the solubility and stability of poorly soluble pharmacological active substances, as they combine the complex forming properties of CDs and properties of polymers (such as the high molecular weight). The affinity of CDs for certain lipophilic molecules is characteristic to the polymeric nano-structured system and allows the development of specific drug delivery systems. Knowing that cyclodextrin capacity to form inclusion complexes is maintained and enhanced when the CD molecules form aggregates, cross-link together or copolymerize with other compounds, we have synthesized cyclodextrin based nanosponges (from β-cyclodextrin and sulfobutylether-β-cyclodextrin). The complexing properties of the polymers were investigated against repaglinide (a hypoglycemic agent, practically insoluble in water). Solubility studies were performed according to the method reported by Higuchi and Connors and the phase solubility diagrams were plotted. The repaglinide-nanosponges complexes were prepared, lyophilized and the resulted inclusion complexes were characterized by FT-IR and NMR. The solubility profile and the loading capacity of the cyclodextrin based polymers were also determined.     

New Method for the Synthesis of 5‐Hydroxycamptothecin Derivatives

Abstract

An efficient hydroxylation at the 5‐position of the C ring of camptothecins was accomplished with the complex of CuI and organic amines as catalyst in the presence of oxygen at room temperature in dimethyl formate (DMF). To be successfully hydroxylated, the insoluble camptothecin analogue was transformed to the corresponding 20 carbonates.