食品中柠檬黄铝色淀和日落黄铝色淀的毛细管区带电泳分析

发展了一种新的采用毛细管区带电泳分析柠檬黄铝色淀和日落黄铝色淀的方法。通过前处理步骤成功实现了铝色淀中铝基质与色素的分离。利用石英毛细管柱（48.50 cm（有效长度40.00 cm）×50 μm）,分别针对柠檬黄铝色淀和日落黄铝色淀进行了电泳条件的优化,并得到最优分离结果。所建立的定量分析方法的检出限对于柠檬黄铝色淀和日落黄铝色淀分别达0.26 mg/L和0.27 mg/L,线性范围分别为0.53~1.3×10²mg/L和0.54~1.4×10²mg/L,两种被分析物的测定重复性（RSD,n=6）分别为4.3%和5.7%,日间重复性（RSD,n=6）分别为5.6%和6.0%。经过更深入研究后,该方法可以发展为食品中相应色淀的检测方法。     

Determining the wettability of granular alumina by aluminum–magnesium alloys using the infiltration method

Wettability of the granular bed media influences the efficiency of aluminum filtration. This project was undertaken to develop a method for determining the wettability of the granular media in order to evaluate its suitability for filtration. The wetting characteristics of different granular alumina particles by aluminum–magnesium alloys were studied using the infiltration method. The contact angles for rough as well as smooth surfaces were determined, and alumina particles were classified according to their wetting characteristics. The results were consistent and showed that it is possible to differentiate the wetting characteristics of different alumina samples with the infiltration method. A capillary model based on the energy balance was developed to analyze the experimental data. The model uses an average capillary pore size. For one type of alumina, this model was extended to carry out the analysis using a capillary pore size distribution. Similar results were found in both cases. This paper describes the experimental and modeling work, and the results are presented and discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Sol-gel multicapillary columns for gas-solid chromatography

In this work, we report the method for the preparation of multicapillary columns (MCCs) for gas-solid chromatography. The porous layer adsorbent is formed on capillary walls by the hydrolysis of aluminum alkoxide in the presence of polypropylene glycol (PPG) and HCl. Porosity and selectivity of the adsorbent depend on reaction conditions and the concentration of PPG. Sol-gel MCCs are well suited for high-speed chromatographic analysis of light hydrocarbons by gas-solid chromatography. Nine-component mixtures of C1-C4 hydrocarbons are separated within 8-12 s. The efficiency of 25-30 cm long alumina sol-gel MCCs consisting of approximately 1400 capillaries of 40 microm diameter is up to 2500-3000 theoretical plates.     

8-羟基喹啉动态有序介孔SiO_2涂层毛细管微萃取与ICP-MS在线联用分析天然水中铝的形态

本文采用溶胶-凝胶方法合成SiO_2溶胶,制备了8-羟基喹啉改性的有序介孔SiO_2涂层毛细管,建立了毛细管微萃取-电感耦合等离子体质谱(CME-ICP-MS)在线联用技术分析铝形态的新方法.选择游离态铝和Al-柠檬酸络合物为不同铝形态的代表物,详细探讨了不同实验参数对铝形态分离的影响.结果表明:8-羟基喹啉改性的有序介孔SiO_2涂层毛细管在pH为5.0～8.0的范围内可以有效地分离试样中的稳定态单核铝(柠檬酸铝)和非稳定态无机单核铝(游离态铝).方法的富集倍数为10,检出限为0.34 ng·mL~(-1).该法应用于湖水、池塘水和长江水中铝的组形态分析,所得结果与8-羟基喹啉负载硅胶微柱分离所得结果吻合很好.     

Hydrophobization of coarse calico by wet treatment in aluminum chloride solutions

This paper describes the method of wet chemistry used for hydrophobization of coarse calico surface. It was found that hydrophobicity of coarse calico surface is achieved by the formation of aluminum oxide on the surface. An experimental plan was drawn up according to the Taguchi method. The effect of soap solution temperature, aluminum chloride solution concentration, sample treatment time in aluminum chloride solution and heat treatment temperature on water absorption, contact angle, capillary absorption and calico moisture content was studied. The dependencies of hygroscopic properties on the process parameters were obtained. Capillary absorption and water absorption of the test samples increased with increasing concentration of aluminum chloride solution. An increase in the processing time of coarse calico samples in an aluminum chloride solution leads to a decrease in the hydrophobicity of the samples. The characteristics of the dependencies of hygroscopic properties on the temperature of heat treatment and the temperature of the soap solution are similar.

     

An on-column capillary gas chromatographic method for the analysis of synthetic pyrethroid residues on fish eggs

A sensitive and reproducible residue method is described for the determination of cypermethrin and deltamethrin in fish eggs. The limit of determination of 0.0005 mg kg^?1 is achieved using only a very small sample size; typical sample weights lie in the range of 0.1-1 g of fathead minnow or trout eggs. The method involves tissue homogenization (tube homogenizer) followed by hot acetonitrile extraction, then sequential C₈, aluminum oxide, and silica gel clean-up. The clean-up is carried out in glass columns using cotton wool plugs in order to minimize potential sample contamination by plasticizers. Residues are determined by capillary chromatography using automated on-column injection with electron-capture detection. Confirmation of residues by gas chromatography-mass spectrometry using selected ion monitoring (SIM), is also described.     

毛细管气相色谱法测定芝麻中多种有机磷农药残留量

建立了芝麻中多种有机磷农药残留量的毛细管气相色谱的测定方法。样品以V(乙腈 )∶V(丙酮 ) =1 0∶1混合溶剂为提取剂 ,应用超声波辅助提取 ,固相吸附层析柱净化m(中性氧化铝 )∶m(弗罗里硅土 ) =1∶1 ,采用GC FPD法同时测定芝麻中的多种有机磷农药残留量。检出限为 0 .0 1 1～ 0 .0 1 7μg mL。方法的回收率为 82 .1 %～ 1 0 9.7%。     

Polystyrene-based blend nanorods with gradient composition distribution

The polystyrene-based polymer blends, partially miscible poly(bisphenol A carbonate)/polystyrene (PC/PS) and completely miscible poly(2,6-dimethylphenylene oxide)/polystyrene (PPO/PS), in nanorods with gradient composition distribution were discussed. The polymer blend nanorods were prepared by infiltrating the polymer blends into nanopores of anodic aluminum oxide (AAO) templates via capillary action. Their morphology was investigated by micro-Fourier transform infrared spectroscopy (micro-FTIR) and nano-thermal analysis (nano-TA) with spatial resolution. The composition gradient of polymer blends in the nanopores is governed by the difference of viscosity and miscibility between the two polymers in the blends and the pore diameter. The capillary wetting of porous AAO templates by polymer blends offers a unique method to fabricate functional nanostructured materials with gradient composition distribution for the potential application to nanodevices.     

Investigation of Model Emulsion Films Stabilized by Solid Particles: Thickness of Films, Their Stability, and Interfacial Tension

The results of studying the thickness and stability in the gravitational field are presented for model emulsion films stabilized by solid particles of aluminum stearate and modified silica. The dependences of the capillary pressure on the thickness upon the creation of reduced pressure in a film (capillary pressure isotherms) are also given. The decrease in the water–oil interfacial tension because of solid particles is experimentally investigated.     

New GC quartz-lined aluminum capillary columns coated with graphitized carbon black modified by liquid phases

Summary Fused silica is by far the best material for most kinds of GC capillary columns but in some particular conditions, when a drastic or alkaline treatment is required, this material and especially the polyimide protector layer do not possess high chemical resistance and could easily break down. In order to overcome this disadvantage, in this paper, we present a new type of column — a quartz-lined aluminum capillary coated with graphitized carbon black modified by liquid phases by using a new coating procedure. With the above material a capillary column for amine analysis, and another for the analysis of VOCs and oil products are obtained. Some characteristic applications of both columns are reported.     

New GC quartz-lined aluminum capillary columns coated with graphitized carbon black modified by liquid phases

Summary Fused silica is by far the best material for most kinds of GC capillary columns but in some particular conditions, when a drastic acidic or alkaline treatment is required, this material and especially the polyimide protector layer do not possess high chemical resistance and could easily break down. In order to overcome this disadvantage, in this paper, we present a new type of column — a quartz-lined aluminum capillary coated with graphitized carbon black modified by liquid phases by using a new coating procedure. With the above material a capillary column for amine analysis, and another for the analysis of VOCs and oil products are obtained. Some characteristic applications of both columns are reported.     

Measurement of the surface tension of liquid marbles

The capillary rise and Wilhelmy plate methods have been used to study the "surface tension" of water marbles encapsulated with polytetrafluoroethylene (PTFE) powders of 1-, 35-, and 100-μm particle size. With the capillary rise technique, a glass capillary tube was inserted into a water marble to measure the capillary rise of the water. The Laplace pressure exerted by the water marble was directly measured by comparing the heights of the capillary rise from the marble and from a flat water surface in a beaker. An equation based on Marmur's model was proposed to calculate the water marble surface tension. This method does not require the water contact angle with the supporting solid surface to be considered; it is therefore a simple but efficient method for determining liquid marble surface tension. The Wilhelmy method was used to measure the surface tension of a flat water surface covered by PTFE powder. This method offers a new angle for investigating liquid marble shell properties. A discussion on the nature and the realistic magnitude of liquid marble surface tension is offered.     

Standardization of aluminum oxide and detection of polycyclic aromatic hydrocarbons on aluminum oxide

Luminescence methods are described for detecting polycyclic aromatic hydrocarbons (6-, 5-, 4-, and 3-ring) on aluminum oxide after separation by dry-column chromatography. A method is reported for standardizing the water content in the aluminum oxide used for dry-column chromatography. A water content of 4.74% was chosen to define the activity of aluminum oxide because there was minimum overlap among the PAH bands.     

Electrothermal volatilization of aluminum as 1-phenyl-3-methyl-4-benzoylpyrazolone[5] chelate for gaseous sample introduction in ICP-AES

Based on gaseous compound introduction as 1-phenyl-3-methyl-4-benzoylpyrazolone[5](PMBP) chelate of aluminum by electrothermal vaporization in ICP-AES, a method for determination of trace aluminum was developed. Trace aluminum was vaporized at temperature of 1000 degrees C, and the vaporization behavior of aluminum chelate was detailedly investigated. Under the optimum conditions, the detection limit of aluminum was 0.6 ng ml(-1), and the relative standard deviation for 0.1 mug ml(-1) aluminum was 4.7% (n=8). The proposed method was applied to the determination of trace aluminum in rice flour reference materials, and the results well agreed with the reference values.     

Evaluation of gas chromatography-mass spectrometry in conjunction with chemometric resolution for identification of nitrogen compounds in crude oil

A chemometric resolution method is described for the identification of nitrogen compounds in crude oil. Prefractionation of crude oil into discrete chemical classes was performed by adsorption column chromatography using small quantities of neutral aluminum oxide and silicic acid. Subsequent high-resolution separation of individual components was achieved by using capillary column gas chromatography, and compound types were detected by mass spectrometer. In conjunction with a combined chemometric method, each principal chemical class was further resolved and separated, which made it possible to identify some nitrogen compounds in the investigated oils. To a certain extent, this method could relieve classical analysis of difficulty in identifying those species with poorly low contents or partially chromatographic overlaps, particularly in the cases where authentic standards were not available for addition into the unknown analytical systems to reveal what indeed existed in them.     

Comparison of Capillary and Skimmer Interfaces in Evolved Gas Analysis-Mass Spectrometry (EGA-MS) with Regard to Impurities in Ceramic Raw Materials

Capillary and skimmer interfaces in EGA-MS were compared by analysis of the carbon substances remaining in the hydrolysis products of aluminum alkoxides. Peaks with higher intensities were detected in the skimmer interface mode than those in the capillary interface mode. It was confirmed in particular that the skimmer interface is effective in increasing the sensitivity for species with higher mass, e.g. the evolved butyl group, as carbon substances remaining in the hydrolysis product of aluminum sec-butoxide. This revised version was published online in July 2006 with corrections to the Cover Date.     

抑制褪色光度法测定油炸面制食品中痕量铝

建立抑制褪色光度法快速测定食品中痕量铝的方法。在硫酸介质中,一定量的铝离子对溴酸钾氧化罗丹明B褪色有抑制作用,据此建立了抑制褪色光度法快速测定食品中痕量铝的新体系,最大吸收波长为550 nm。在1 mol/L硫酸介质中,铝含量在0.07~0.4μg/mL范围内与吸光度具有良好的线性关系,相关系数r=0.9995,检出限为0.02μg/mL。用该方法测定油炸面制食品中痕量铝,测定结果的相对标准偏差为1.3%~3.1%(n=11),加标回收率为99.3%~103.5%。该方法测定结果准确可靠,可用于食品中痕量铝的测定。     

顶空毛细管柱气质联用法测定饮用水中15种挥发性有机物

采用顶空毛细管柱GC–MS法测定饮用水中卤代烃、苯系物、氯苯等15种挥发性有机物。色谱柱为DB–624石英毛细管柱(60 m×0.25 mm,1.8μm),程序升温,直接进样顶空毛细管柱气质联用法同时测定饮用水中15种挥发性有机物。该方法具有良好的线性,线性相关系数均大于0.996。方法的检出限为0.10~0.22μg/L。15种挥发性有机物的平均回收率在94%~103%之间,测定结果的相对标准差为2.9%~6.7%(n=7)。该方法简便、快速,检测结果均能满足GB 5749–2006检测要求。     

Calibration of an optical condensate measurement technique using indirect static headspace gas chromatography.

Researchers in the Department of Mechanical Engineering seek to obtain a means to measure less than 3 mg of H2O that adheres to a metal surface as condensate. The objective is to calibrate optical reflectance measurements of an aluminum surface as a function of the condensate thickness present. Collaboration with the Hazardous Substance Research Center at Michigan State University results in the development of an indirect static headspace gas chromatographic technique capable of measuring H2O in low-milligram quantities. The technique utilizes manual headspace sampling, a megabore capillary column, and a flame ionization detector. A correlation of r2 = 0.999 is obtained for the calibration of the indirect measurement technique. The calibration of the analytical instrument demonstrates adequate precision (< +/- 50 microg at a 95% confidence interval) for such a heterogeneous sample. The calibration samples consist of a strip of aluminum metal, H2O, and pulverized calcium carbide to convert the H2O to acetylene. A scaled calibration technique is used to simplify handling trace water volumes. The surface reflectance measurements are found to correlate well (r2 = 0.935) with measurements of the condensate mass. This result facilitates the development of an optical mass-transfer measurement technique. This study focuses on the analytical method and its relationship with engineering research.     

镍氢蓄电池材料用氧化锆布膜中铝含量的分析测试技术

运用N2O-C2H2火焰原子吸收光谱法进行镍氢蓄电池材料用氧化锆布膜中铝含量的分析测试技术,建立了铝的共振线、灯电流、火焰燃烧比等最佳实验条件．显示出该方法具有很好的灵敏度和重现性,具有操作简便、容易掌握、分析周期短、干扰小等优点．测定样品铝含量的相对标准偏差均小于1．0％（n=6）．标准加入回收率均在97．5％～98．6％范围内．适用于镍氢蓄电池材料用氧化锆布膜中铝含量的控制分析和样品系统分析．