氧弹燃烧-离子色谱法测定电子产品连接线中的卤素

建立了氧弹燃烧法处理电子产品连接线,离子色谱测定样品中卤素的分析方法。选用TSK-gelSuperIC-AZ阴离子分析柱,以NaHCO3(7.5mmol/L)+Na2CO3(1.1mmol/L)为流动相等度洗脱,抑制电导检测。结果表明,该条件下F-浓度在0.02～2mg/L,Cl-和Br-浓度在0.05～5mg/L范围内峰面积与浓度的线性关系良好(r>0.999),实际样品中卤素回收率为90.52%～97.24%,样品测定结果相对标准偏差均为0.73%～2.01%(n=5)。应用氧弹燃烧-离子色谱法测定电子产品连接线中的卤素离子,方法简便、快捷,测定结果准确。     

Precise and accurate determination of halogens in organic compounds using an amalgamated gold electrode

Precise and accurate titration of halogens in organic and inorganic materials has been studied. The halogen was titrated with coulometrically generated silver and determined potentiometrically by using an amalgamated gold indicator electrode. An argentometric titration curve using the amalgamated gold indicator electrode showed a large jump in potential at the endpoint as well as in mercurometric determination. Sodium carboxymethyl cellulose (CMC) and aluminum nitrate were added as they are most effective for clarifying the sample solution and eliminating adsorption of the halide ion on the silver halide generated. The electrolytes used were 0.5 M nitric acid containing 0.1% CMC and 0.2 M aluminum nitrate. Approximately 0.2 mmol of chloride, bromide, and iodide ions were titrated with high precision and accuracy. Their standard deviations were 0.03, 0.02, and 0.02%, respectively, with no apparent systematic error. The precise determination of halogens, employing oxygen flask combustion and dissolution of the halide salts in the electrolyte, was carried out with ±0.1% absolute error using samples weighing between 20 and 30 mg.     

Chemical separation of enriched cadmium target from copper backing in cyclotron production of radioisotope 111In

A radiochemical purification procedure was developed for the separation of enriched cadmium (¹¹¹Cd and ¹¹²Cd) from natural copper that used as backing; and was based upon the chromatographic adsorption. The separation of copper from cadmium was studied in this work. The ions were selectively separated from aqueous solution. Ion-exchange chromatography was employed as a column (1.5 cm i.d. and 15 cm length) with AG1-X8 resin (chloride form, 100–200 mesh) and a flow rate of 1–2 ml/min throughout the separation. 6 M HCl media was used for the adsorption of Cd and Cu on the resin. Then, Cu was eluted by 2 M HCl and Cd by 100 ml 0.5 M HNO₃. The amount of Cu and Cd ions in the final solution (0.5 M HNO₃) were measured by pulse polarographic method and the concentration of Cu was found to be <0.1 ppm. The Cd was quantitatively recovered and the recovery yield from ion-exchange chromatography was greater than 96 %.     

氧弹燃烧-离子色谱法测定煤中氯含量

建立了氧弹燃烧-离子色谱测定煤中氯含量的方法.在加有(NH4)2CO3溶液和过量氧气的氧弹中燃烧煤样,释放的氯被(NH4)2CO3溶液吸收,过滤溶液后, 采用离子色谱外标法测定滤液中氯的浓度,最后计算出煤中氯的含量.色谱工作条件:淋洗液为1.8 mmol/L Na2CO3与1.7 mmol/L NaHCO3混合液,流速1 mL/min;再生液为40 mmol/L H2SO4,流速0.5 mL/min;进样量20 μL.色谱标准工作曲线线性相关系数0.9996;10次测定1 mg/L Cl-标准溶液的均值为1.0012 mg/L,相对标准偏差为1.34%;8个煤样加标回收率为90.7%～104.3%;测定标准物质GBW11119 及GBW11120的相对误差分别为1.75%和1.36%;对比研究显示,氧弹燃烧-离子色谱测定8个煤样(除两个煤样外)氯含量结果远高于艾士卡剂混合熔样-离子色谱测定结果,表明艾士卡剂混合熔样过程由于煤样未处于完全密闭状态导致部分氯的散失.     

Development of Polymeric Resin Ion‐exchanger Based Chloride Ion‐selective Electrode for Monitoring Chloride Ion in Environmental Water

A chloride ion‐selective electrode (ISE) membrane was developed by using a copolymeric ion‐exchanger resin (trimethyl ethenyl quaternary ammonium chloride polystyrene‐divinylbenzene copolymer resin, TMEQAC PSDVB), the ionophore ({μ‐[4,5‐Dimethyl‐3,6‐bis(dodecyloxy)‐1,2‐phenylene]}bis(mercury chloride), ETH9033), the plasticizer (bis(2‐ethylhexyl) sebacate, DOS), and the membrane substrate (polyvinylchloride, PVC). At 25 °C, the electrode exhibited an ideal Nernstian response of 59.2 mV/decade with the linear calibration concentration range from 1.0 × 10^?4‐1.0 × 10^?2 M (r² = 0.9930). The limit of detection was 2.45 ppm (6.9 × 10^?2 mM) and the measurement response time was less than 10 seconds. The working temperature range of electrode was 10‐45 °C. The working pH range for chloride ion measurement was 2.0‐11.0. Among the various anions examined in this work, only I^?, SCN^?, and MnO₄^? ions show significant interference to the electrode measurement. The chloride ISE can be used at least 72 days. The determination of chloride ion content in three kinds of environmental water sample with the electrode method was accurate (92‐95%) and precise (RSD < 4.4%) and did not show significance difference from the high‐performance liquid chromatography method.     

Evaluation of sample preparation methods for elastomer digestion for further halogens determination

In this work, three sample preparation methods were evaluated for further halogen determination in elastomers containing high concentrations of carbon black. Samples of nitrile-butadiene rubber, styrene-butadiene rubber, and ethylene-propylene-diene monomer elastomers were decomposed using oxygen flask combustion and microwave-induced combustion (MIC) for further Br and Cl determination by ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP OES), and inductively coupled plasma mass spectrometry (ICP-MS). Extraction assisted by microwave radiation in closed vessels was also evaluated using water or alkaline solution. Digestion by MIC was carried out using 50 mmol l⁻¹ (NH₄)₂CO₃ as the absorbing solution. The effect of the reflux step was also evaluated. Accuracy was evaluated using certified reference materials with polymeric matrix composition and by comparison of results using neutron activation analysis. Agreement for Br and Cl was better than 95% by MIC using 5 min of reflux, and no statistical difference was found using IC, ICP OES, and ICP-MS for determination of both analytes. For MIC, the relative standard deviation (RSD) was lower than 5%. Using extraction in closed vessels, a high amount of residues was observed, and recoveries were lower than 45% for both analytes. For oxygen flask combustion, the agreement was similar using MIC but RSD was higher (20%). The residual carbon content, an important parameter used to evaluate the digestion efficiency, was always below 1% for MIC. Using MIC, it was possible to digest elastomers with high efficiency, resulting in a single solution suitable for halogen determination by different techniques.     

Determination of sulfate and chloride ions in highly saline oilfield water by capillary electrophoresis using bilayer-coated capillaries and indirect absorption detection

Analysis of highly saline oilfield waters for anions presents challenges. Traditional analytical techniques used for such analysis tend to suffer from both poor sensitivity and selectivity due to the high concentrations of salt present in the samples. A capillary electrophoresis method was developed for the simultaneous determination of chloride and sulfate anions which is relevant to the oilfield analysis industry and of economic value. Due to the extremely high concentrations of chloride in highly saline oilfield waters, it is difficult to achieve baseline electrophoretic separation necessary for accurate quantitation. By using a capillary with a noncovalently bound bilayer coating using Polybrene, a cationic polymer and sodium dodecyl sulfate (SDS), an anionic surfactant and a buffer consisting of 50 mM TRIS, 30 mM SDS, 5% methanol and 26 mM chromium trioxide (CrO₃) at pH 6.7, baseline separation (R_s > 1.5) of chloride and sulfate was achieved. To mimic possible oilfield water samples, model water solutions of 5%, 10%, 15% and 20% chloride containing low ppm sulfate were prepared and successfully analysed using the method developed. In addition, the method was applied to determine chloride and sulfate anions in highly saline oilfield water samples. The accuracy of the method developed was verified by analysing NIST certified standards of chloride and sulfate. The results obtained for chloride and sulfate with the indirect CE-UV method were in close agreement (94–100% accuracy; <2.5% relative standard deviations) with those of the certified standard analysed by ion chromatography.     

Determination of Bromide,Chloride, and Fluoride in Cigarette Tobacco by Ion Chromatography after Microwave-Induced Combustion

A microwave-induced combustion (MIC) method was applied for cigarette tobacco digestion and further determination of bromide (Br), chloride (Cl), and fluoride (F) by ion chromatography (IC). Samples (up to 500 mg) were combusted at 20 bar of oxygen. Combustion was complete in less than 30 s, and analytes were absorbed in (NH₄)₂CO₃ solutions. A reflux step, not available in other systems, was applied to improve analyte absorption. Absorbing solution with 50 mmol L^?1(NH₄)₂CO₃ was selected because it showed recovery close to 100% for samples containing spikes of halogens. Accuracy of the proposed procedure was evaluated by analysis of certified reference materials and the agreement was better than 97% for all analytes using 50 mmol L^?1 (NH₄)₂CO₃ as absorbing solution and 5 min of reflux. Temperature during combustion was higher than 1400°C and the residual carbon content was always lower than 1%. With the use of the MIC system, up to eight samples could be processed simultaneously, and a single absorbing solution was suitable for all analytes. Limits of quantification by MIC and further IC determination were 0.50, 0.20, and 0.10 µg g^?1 for Br, Cl, and F, respectively.     

Evaluation study on properties of isohexyl-BTP/SiO2-P resin for direct separation of trivalent minor actinides from HLLW

In order to develop a direct separation process for trivalent minor actinides from fission products in high level liquid waste (HLLW) by extraction chromatography, a novel macroporous silica-based 2,6-bis(5,6-diisohexyl)-1,2,4-triazin-3-yl)pyridine resin (isohexyl-BTP/SiO₂-P resin) was prepared. The content of isohexyl-BTP extractant in the resin was as high as 33.3 wt%. The resin exhibited much higher adsorption affinity for Am(III) in 2–3 M (mol/L) HNO₃ solution over U and FP which are contained in HLLW. The kinetic data were analyzed using pseudo-second-order equation. The results suggested that the Eu(III), Gd(III), and Dy(III) adsorption was well explained by the pseudo-second-order equation. Quantitative desorption for adsorbed elements was achieved by using H₂O or thiourea as eluting agents. However, the kinetics of adsorption and desorption were rather slow and this drawback needs to be resolved. Stability of the resin against HNO₃ was also examined. It was found that the resin was considerably stable against ≤4 M HNO₃ solution for the reasons of an extremely small leakage of the extractant into the solution from the resin and the adsorption performance keeping for rare earths in 3 M HNO₃ solution.     

氧弹燃烧-离子色谱法测定原油标准物质中硫含量

采用氧弹燃烧-离子色谱法对原油标准物质中的硫含量进行定值。研究了样品燃烧条件,对方法的可靠性进行了验证,分析了空白量、溶液中基体、仪器测量值漂移、吸收液等因素对测量结果的影响,方法的扩展不确定度不大于2.0%。     

Determination of Homologue Imidazolium Ionic Liquid Cations by Ion Chromatography Using a Carboxyl Acid Cation-Exchange Column with Direct Conductivity Detection

An investigation into the determination of four imidazolium ionic liquid cations by ion chromatography using a carboxyl acid cation exchange column and direct conductivity detection was carried out. This research has developed a simple, selective, and accurate ion chromatographic method for separation of imidazolium ionic liquid cations. Detection limits (S/N = 3) for the cations were 3.2–24.3 mg/L. Relative standard deviations (RSD, n = 5) for peak areas were less than 1.6%. The method has been successfully applied to the determination of two ionic liquids synthesized by organic chemistry lab.     

Simultaneous ultramicrodetermination of heterogeneous halogens in organic compounds

The simultaneous ultramicrodetermination of heterogeneous halogens in organic compounds was carried out by the potentiometric titration with 0.002 M silver nitrate after the sample was decomposed by the flask combustion method. In examination of the titration, it was found that clear potential break at the end point was obtained by controlling the delivery speed of the titrant at 0.2 ml/min or slower and the temperature of the solution to be titrated at ca. 10 °C when chloride ion is present. The error due to coprecipitation during the titration and the effect of the mole ratio of heterogeneous halide ions in the sample solution was examined and discussed. The analysis of organic halogen compounds resulted in an error of within 0.4% and standard deviation of less than 0.25%.     

Enrichment of total steroidal saponins from the extracts of Trillium tschonoskii Maxim by macroporous resin and the simultaneous determination of eight steroidal saponins in the final product by HPLC

An effective and simple method was established for the separation and enrichment of steroidal saponins from Trillium tschonoskii Maxim. The adsorption and desorption properties of seven macroporous resins were investigated. Among the tested resins, AB‐8 resin showed the best adsorption and desorption capacities. The adsorption of steroidal saponins on AB‐8 at 25°C was quite consistent with both the Freundlich isotherm model and the pseudo‐second‐order kinetics model. By optimizing the dynamic adsorption and desorption parameters, the content of steroidal saponins increased from 5.20% in the crude extracts to 51.93% in the final product, with a recovery yield of 86.67%. Furthermore, by scale‐up separation, the concentration and recovery of total steroidal saponins were 43.8 and 85.5%, respectively, which suggested that AB‐8 resin had great industrial and pharmaceutical potential because of its high efficiency and cost‐effectiveness. In addition, a high‐performance liquid chromatography method for the simultaneous determination of eight steroidal saponins was established for the first time, which was employed to qualitatively and quantitatively analyze the final product. Based on the methodological validation results, the high‐performance liquid chromatography method can be widely applied to the quality control of steroidal saponins from Trillium tschonoskii Maxim due to its excellent accuracy, stability, and repeatability.     

Isolation and enrichment of Ginkgo biloba extract by a continuous chromatography system

In this study, an effective method was developed for the isolation and enrichment of Ginkgo biloba extract by continuous chromatography system. The adsorption and desorption ratio of flavonoids as main index, the best macroporous resin was screened out from six resins by static adsorption and desorption tests. At the same time the adsorption and desorption parameters were optimized by dynamic adsorption and desorption tests. Under optimal parameters, five operations consisting of loading, washing, desorbing, regenerating, and balancing were integrated across the continuous chromatography system for the purpose of refining 66 L of crude extract solution. The results were as follows, 198.22 g of Ginkgo biloba extracts was produced, which contained 65.83 g of flavonoids and 15.44 g of lactones. The content of flavonoids and lactones increased from 2.76 and 0.72% in the crude extract to 33.21 and 7.79%, with a recovery yield of 91.26 and 81.21%. Methodology validation showed that the proposed method had high stability and reproducibility. Compared with the traditional macroporous resin method, the proposed method had a short processing time and low solvent consumption. Our studies indicated that the newly developed method is an effective procedure for the isolation and enrichment of Ginkgo biloba extract.     

Synthesis of the hydrophobic–hydrophilic macroporous poly divinylbenzene/poly(sodium acrylate) IPN resin and adsorption performance for berberine

The macroporous polydivinylbenzene/poly(methyl acrylate) interpenetrating polymer network (PDVB/PMA IPN) was prepared by the sequential suspension polymerization method, and was modified to be hydrophobic–hydrophilic macroporous polydivinylbenzene/poly (sodium acrylate) IPN (PDVB/PNaA IPN) by converting the PMA to PNaA under the condition of base. The effects of different mass ratio of the two networks and different cross‐linking degree of the second network on the pore structure and adsorption capacity of PDVB/PNaA IPN resin were studied. The PDVB/PNaA IPN resin whose adsorption quantity is the biggest was chosen to study further. The pore structure, the weak acid exchange capacity, the water retention capacity, and the swelling ability of PDVB/PNaA IPN resin were measured. The study focused on the adsorption isotherms of berberine at different temperatures. Isosteric adsorption enthalpy, adsorption Gibbs free energies can be calculated according to thermodynamic functions. The results show that the saturated adsorption quantity of berberine is up to 109.4 mg ml^?1 (wet resin) by the way of dynamic adsorption and desorption experiment. The resin could be reused by the mixture with 0.5% sodium chloride and 80% ethanol. On the one hand the hydrophobic PDVB in the PDVB/PNaA IPN resin has the ability of adsorption using π–π interaction, and on the other hand the hydrophilic PNaA in the PDVB/PNaA IPN resin has the ability of adsorption using ion exchange interaction. An important conclusion can be drawn that the PDVB/PNaA IPN resin has a promising application prospect in extracting and separating quaternary ammonium type alkaloids such as berberine. Copyright © 2009 John Wiley & Sons, Ltd.     

大孔吸附树脂对辣椒素类物质的富集

辣椒;辣椒素;辣椒素类物质;吸附树脂;分离     

采用大孔型树脂除去照相明胶中微量Fe3+的研究

利用大孔树脂吸附和分离照相明胶中的微量铁，比较了6种树脂对微量铁的吸附效果，讨论了温度等因素对树脂吸附微量铁的影响．结果显示，D412大孔螯合树脂对铁的吸附效果较好；宜选用NaCl和络合剂EDTA混合溶液将树脂再生转化为Na型；采用D412大孔螯合型、732强硬型和711强碱型3种树脂的串联组合处理方式，除铁效率达50%-90％；容液pH值对Fe^3 在D412树脂上的吸附行为影响较小．     

Pyrohydrolysis Coupled to Ion Chromatography for Sensitive Determination of Iodine in Food-Related Materials

For the determination of iodine in food-related materials, the biological sample was decomposed using a pyrohydrolytic procedure. A sample vessel made from mullite, in which an aliquot of sample was taken, was placed in a quartz tube, and heated at 100°C through 820°C step by step under wet oxygen flow. Iodine in the sample was separated by evaporation as hydrogen iodide and collected in a dilute sodium hydroxide solution. After the basic solution containing the analyte was neutralized by adding hydrochloric acid, iodine in the solution was determined by using ion chromatography with ultraviolet absorption detection. The operating conditions for the pyrohydrolytic decomposition procedure were examined. Under the optimized conditions, organic constituents in the sample were completely decomposed since the analyte species were converted to the iodide ion. The detection limit of 0.01 µg g^?1 iodine was established with a reproducibility of 1.2% when a sample of 500 mg was taken. This method was applied to the determination of iodine in various certified reference materials and food samples with satisfactory results.     

Dabsyl chloride derivatisation of melamine followed by high-performance liquid chromatography determination in water samples

A new and sensitive precolumn derivatisation with dabsyl chloride was developed for the analysis of melamine in water samples by high-performance liquid chromatography (HPLC) with visible detection. Derivatisation with dabsyl chloride leads to improving sensitivity and hydrophobicity of melamine. Under optimum conditions of derivatisation and microextraction, the method yielded a linear calibration curve ranging from 10 to 2000 µg L^?1 with a determination coefficient (R²) of 0.9952. Limit of detection (LOD) and limit of quantification (LOQ) were 2.0 and 6.0 µg L^?1, respectively. The relative standard deviation per cent (RSD%) for intraday and inter-day extraction and determination at 20 and 200 µg L^?1 levels of melamine was less than 8.2% (n = 6). Finally, the proposed method was successfully applied for the determination of melamine in different water samples and satisfactory results were obtained (relative recovery ≥91%).     

Acetohydroxamate Resin as Column Packing for Ion Chromatography

A chelating resin with acetohydroxamate functional groups was synthesized and used as the stationary phase in ion chromatography for the determination of copper. As the reaction mechanism was mainly complexation, the coordination behavior of the synthesized resin toward Cu(II) was studied by means of EPR, IR and electronic spectrometry and potentiometry. The kinetic study shows that the resin is suitable for use in ion chromatography. We employed a resin column 250 mm long by 3 mm I.D. in conjunction with a mixture of hydrochloric acid and acetone as mobile phase for the determination of Cu(II). Detection of the chromatography system was carried out via post-column derivatisation of the column effluent with PAR at 520nm. The detection limit is 0.22ppm, and the relationship was linear in the range 0.25-1.20ppm. We investigated the effect of other metal ions, As(V), Cd(II), Cr(III), Hg(II), Ni(II), Pb(II) and Zn(II), or foreign ligands, EDTA, ascorbic acid, humic acid or sodium chloride on the determination of Cu(II) ion. A concentration column packed with acetohydroxamate resin combined with the above separation system was also used to determine of copper ion; the dynamic range is 2-15 ppb and the detection limit is 0.70ppb. The proposed system was applied to the analysis of Cu(II) in sea water.