Synergic effects in the extraction of paracetamol from aqueous NaCl solution by the binary mixtures of diethyl ether and low molecular weight primary alcohols

Liquid-liquid extraction of paracetamol from aqueous NaCl solutions was performed with diethyl ether, 1-propanol, 1-butanol, isobutanol, 1-pentanol, and binary mixtures diethyl ether/1-propanol, diethyl ether/1-butanol, and diethyl ether/isobutanol. Among the pure solvents investigated in this study best extraction efficacy was obtained with 1-butanol. Synergic effects in the extraction with binary mixtures was investigated and compared with some other systems used for the extraction of poorly extractable compounds. Results obtained in this study may be of both fundamental and practical importance.     

毛细管气相色谱法测定二乙基二硫的含量

采用毛细管气相色谱法(GC)测定了二乙基二硫的含量.结果表明,二乙基二硫含量在0.01⁰.4g/L范围内具有良好的线性关系,平均回收率为99.91%;该方法简便、准确、重复性好,可方便地用于二乙基二硫含量的测定.     

Determination of organophosphorus pesticides in aqueous samples by on-line membrane disk extraction and capillary gas chromatography

Summary A fast and simple procedure for the analysis of aqueous samples by on-line membrane disk extraction and capillary gas chromatography (GC) is presented. As an example, organophosphorus pesticides are preconcentrated from aqueous samples on three 0.5 mm thick, 4.2 mm diameter extraction disks. The layers are dried by a stream of nitrogen (10–15 min; ambient temperature). Desorption of the analytes is carried out with ethyl acetate which is directly introduced into a retention gap under partially concurrent solvent evaporation conditions, using an early solvent vapour exit. The final analysis is carried out by GC with thermionic detection. The technique is applied to the determination of a series of organophosphorus pesticides in tap water and water from two European rivers. With a sample volume of only 2.5 ml, detection limits of 10–30 ppt are achieved in tap water and of 50–100 ppt in river water.     

微蒸馏气相色谱法测定水中低级脂肪醇的研究

考察了微蒸馏气相色谱法测定水样中多种低级脂肪醇的可行性。利用微蒸馏技术将水中的醇分离富集,用程序升温气相色谱法测定。正丙醇、异丙醇、正丁醇、异丁醇、正戊醇、异戊醇的浓缩倍数分别为169．3,137．6,197．4,149．2,142．7,126．0。检出限分别为0．021,0．031,0．032,0．032,0．066,0．065mg／L。样品中所存在组分的平均回收率分别为甲醇82．60％,正丙醇93．25％,正丁醇94．88％;相对标准偏差分别为甲醇7．7％,正丙醇4．7％,正丁醇3．4％。方法适用于水中多种微量低级醇的同时分析。     

Rapid on-line analysis of low molecular weight hydrocarbons using glass capillary gas chromatography

Rapid analysis is important for on-line chromatography. Gaseous or vaporized samples have been injected via heated gas sampling valves of less than 500 μl dead volume. The critical sampling and split problems could be solved by temperature programming. The general analysis described could be successfully used inter alia in scouting reactions.     

毛细管气相色谱法测定菜籽油中脂肪酸组成

采用FFAP毛细管气相色谱法对菜籽油的各组分进行了定性和定量分析.结果表明菜籽油中至少含有从肉豆蔻酸(C140)至鲨油酸(C240)共15种脂肪酸甘油酯.四次平行分析显示各成分含量的标准偏差低于0.33%,绝对偏差不超过0.70%.     

Determination of disulfoton in surface water samples by cloud-point extraction and gas chromatography

This article proposes an alternative method, using cloud-point extraction and gas chromatography, for extraction and determination of disulfoton in water samples. For cloud-point extraction, the nonionic surfactant Triton X-114 was used. Before gas chromatography, a cleanup stage for surfactant removal from the extracts was optimized. Cleanup used two columns, in series, containing silica gel and Florisil, with methanol:hexane (1?:?1) as eluent, resulting in the removal of more than 95% of the Triton X-114. Factors such as ionic strength (>0.5?mol?L^?1) and surfactant concentration (1.0% w/v) increased the extraction efficiency of the cloud-point methodology, yielding disulfoton recoveries of almost 100%. Compared with liquid–liquid extraction, the cloud-point methodology was more efficient, with a better detectability, and resulted in a significant reduction in solvent volume.     

Analysis of alkylbenzene samples by comprehensive capillary liquid chromatography x capillary gas chromatography

The constituents in synthetic alkylbenzene samples were analyzed by a comprehensive capillary liquid chromatography (micro-LC) x capillary gas chromatography (CGC). The micro-LC separates the mixture into aliphatic compounds, monosubstituted alkylbenzenes, multisubstituted alkylbenzenes and binuclear aromatic compounds. Each fraction from a single micro-LC injection is stored in turn in a multiloop interface, and then transferred online into CGC sequentially with large volume in-column splitless injection technique for detailed analysis. No sample discrimination was found with this coupling and injection technique. Both the micro-LC column dimension and transfer speed of fraction from interface to CGC were optimized. Quantitative results and the carbon number distribution of each chemical class are obtained by using the comprehensive micro-LC x CGC with flame ionization detection. The reproducibility of peak area is better than 2% RSD.     

Determination of methylmercury in biological samples by capillary gas chromatography with electron capture detection

A precise and accurate method has been developed for the determination of methylmercury in biological material using capillary gas chromatography with electron-capture detection. Homogenized fish or mussel samples were digested with acid, spiked with ethylmercury chloride as an internal standard and extracted with toluene. After treatment of the solvent extract with sodium thiosulphate and cupric bromide the alkylmercurials were extracted into benzene as their bromide derivatives and analyzed using an OV-275 coated glass capillary column. The detection limit of the method for methylmercury was 5 g/kg tissue.     

Determination of low molecular weight aliphatic amines by HPLC in environmental water samples

A high resolution liquid chromatographic method is described for determination of low molecular weight (LMW) aliphatic amines in environmental waters. The analytes after isolation are derivatized by fluram and separated with isocratic elution on octyl (C₈) column, followed by fluorimetric detection in 395/495 nm. Different isolation procedures such as octadecylsilane (ODS) and strong cation exchanger (SCX) solid phase extraction (SPE) cartridges and Amberlite CG-120 resin were evaluated. The quantitative characteristics such as recovery, linear dynamic range, correlation coefficient, limit of detection (LOD), and relative standard deviation (RSD) are presented. Using this method, aliphatic amines were analyzed in rain and tap water as well as in waste water.     

毛细管电泳法测定肝素和低分子量肝素平均硫酸化程度

肝素和低分子量肝素(LMWHs)作为临床上常用的抗凝血药物,其抗凝血活性与硫酸化程度(SD)密切相关。然而,肝素类药物的生产需经历一系列复杂的工艺过程,在制备和储存过程中,肝素的硫酸基团容易水解丢失,影响抗凝血活性,这将直接影响肝素药物的使用安全性。为保证产品质量,需要发展一种快速检测肝素硫酸化程度的技术,以监测原料质量和工艺条件的稳定性。虽然已有一些测定肝素硫酸化程度的报道,但这些方法均有局限性,不适用于肝素生产的质量控制。为此,开发了一种基于毛细管电泳技术(CE)检测肝素和低分子量肝素的平均硫酸化程度的方法。首先,用肝素酶混合液彻底消化未分级肝素(UHF)和低分子量肝素,然后用毛细管电泳分离酶解得到的所有寡糖和二糖构建模块,并对它们进行定性和定量分析。随后,根据每种寡糖和二糖的峰面积及其硫酸酯基团的数量,便可计算出每个构成肝素二糖单元硫酸化程度的平均值。使用该方法对来自两个生产商各4个批次依诺肝素(低分子量肝素)和5个批次肝素原料进行检测,并计算了各批次样品的相对标准偏差(RSD),对不同厂家生产的依诺肝素平均硫酸化程度进行了比较,验证了该方法的实用性。该方法灵敏度高,准确可靠,分...     

Determination of organic acids of low molecular weight and phosphate in soil by capillary electrophoresis

Capillary zone electrophoresis with indirect UV detection at 254 nm was found to be suitable for the determination of organic acids and phosphate in aqueous extracts of soil. The best support electrolyte solution was found to be 10 mM p-hydroxybenzoic acid with 0.5 mM tetradecyltrimethylammonium bromide to reverse electroosmotic flow. This methodology was tested with 9 analytes found in soils: acetate, citrate, formate, phosphate, lactate, oxalate, pyruvate, succinate, and tartrate. The results obtained show that the methodology is adequate for most of the analytes. The sensitivity to oxalate and citrate was low, and the high concentrations of major inorganic anions interfered with the detection of the former. The methodology was applied to the analysis of aqueous extracts of soil samples. Formate, phosphate, lactate, and acetate anions were detected in most of the samples.     

Determination of phospholipid fatty acids in biological samples by solid-phase extraction and fast gas chromatography

A new method for the determination of phospholipid fatty acids in biological samples, combination of solid-phase extraction (SPE) and fast gas chromatography (GC) was developed. Its application to human plasma and human erythrocytes showed to be robust and reliable for quick and correct identification in routine analysis.     

Determination of urinary succinylacetone by capillary gas chromatography

The average analytical recovery of succinylacetone added to urine and separated by capillary gas chromatography was 69% for solvent extraction and 72% for anion exchange separation. Treating succinylacetone with hydroxylamine hydrochloride at a pH of less than 5 caused formation of a derivative separated by capillary gas chromatography into two isomers: 3-methyl-5- isoxazole propionate and 5-methyl-3- isoxazole propionate as their trimethylsilyl derivatives (molecular weight 227). In a pH greater than or equal to 5, succinylacetone dioxime was formed and separated into 3 isomers as their trimethylsilyl derivatives (molecular weight 404). Succinylacetone dioxime was converted to 3(5)-methyl-(3)5- isoxazole propionate whenever the pH of the solution was dropped to less than 5. Mass spectra of both derivatives are shown. This study demonstrates that capillary gas chromatography is suitable for use in urinary succinylacetone determination.     

毛细管气相色谱法测定邻氨基苯甲酸甲酯的含量

应用气相色谱法测定邻氨基苯甲酸甲酯的含量.采用氢火焰离子化检测器,色谱柱为OV1701毛细管柱,柱温200℃,检测器温度260℃,氮气做载气,流速1.2 mL/min.实验表明在上述色谱操作条件下,邻氨基苯甲酸甲酯的浓度在5.0~40.0 g/L范围内具有良好的线性关系,平均回收率为99.49%.该方法简便、准确、重复性好,可用于工业邻氨基苯甲酸甲酯的含量测定.