水中微量苯胺类化合物的重氮化耦合荧光猝灭法测定

基于亚硝酸根-苯胺类化合物-2-萘酚重氮化-耦合反应体系对2-萘酚的荧光猝灭作用,建立了荧光猝灭法检测水中微量苯胺类化合物的新方法.方法的激发波长为353 nm,发射波长为418 nm.在所选定的实验条件下,测定苯胺、对硝基苯胺、邻硝基苯胺的线性范围分别为:0～640 μg/L,0～720 μg/L和0～740 μg/L,检出限分别为0.017 9、0.020 5、0.026 5 mg/L.方法用于环境水样中的苯胺类化合物的测定,回收率为98%～103%.     

高效液相色谱荧光法测定全棉织物中微量苯胺和二苯胺

建立了全棉织物中苯胺、二苯胺的高效液相色谱荧光分析方法。全棉织物采用乙腈/甲苯(3/1,V/V)为提取剂,以Carb/PSA固相萃取小柱进行净化,在Kromasil C18柱(250 mm×4.6 mm i.d.,5μm)上以水/乙腈(25/75,V/V)为流动相进行分离,采用荧光法进行检测,荧光检测波长λex为280 nm,λem为340 nm。结果表明,苯胺、二苯胺的低、中、高3个加标水平下的平均回收率分别为97.3%~103.5%和98.0%~103.4%,相对标准偏差分别为1.4%~4.2%和0.98%~4.7%,方法的检出限分别为0.3μg/kg和0.2μg/kg,定量限分别为1.0μg/kg和0.5μg/kg。采用该方法对购自市场的30份全棉织物进行检测,其中1份检出苯胺,2份同时检出苯胺和二苯胺。     

在线液膜萃取富集流动注射荧光光度法测定水中痕量苯胺

设计并制造了用作苯胺在线富集的夹板式液膜(SSLM)萃取的流动注射分析装置。磷酸三丁酯用作流动载体,煤油为膜溶剂,试样中苯胺在SSLM萃取单元中得到分离和富集。SSLM萃取体系中pH 3盐酸溶液用作内相,pH 11氢氧化钠溶液用作外相。TBP溶液的适宜浓度为12%,富集时间为10 min,对经富集后pH 11碱性溶液中苯胺所产生荧光的强度进行测定。激发波长eλx为282 nm,发射波长eλm为345 nm,方法的检出限为0.2μg.L-1,苯胺浓度在1~150μg.L-1之间保持线性关系。将此方法用于测定河水中苯胺,根据分析结果算得RSD值均小于5%,回收率在97.6%至100.6%之间。     

支持向量回归-分光光度法对苯酚、苯胺和苯甲酸的同时测定

用支持向量回归(SVR)结合分光光度法对苯酚、苯胺、苯甲酸进行了同时测定.在230～300 nm的波长范围内,用SVR方法建立校正模型,用留一交叉验证的方法优化SVR方法建模,并对苯酚、苯胺、苯甲酸的模拟样品进行了测定.苯酚、苯胺、苯甲酸的预测结果的回收率在98.1%～101.1%之间.     

同步荧光法测定功能饮料中维生素B2和B6的研究

研究了测定功能饮料中维生素B2和B6的同步荧光分析法。确定了最佳实验条件:波长差Δλ为70 nm,扫描速度为150 nm/min,入射和出射狭缝宽度均为10 nm,测定波长:B2为448 nm,B6为323 nm。标准曲线在0.01~0.15μg/mL线性良好,维生素B6和B2的平均回收率分别为96.4%~98.5%和98.3%~100.0%。方法可用于功能饮料中维生素B2和B6的测定。     

苯胲电解液的高效液相色谱分析

利用高效液相色谱，采用以苯甲酸为内标，分析了苯胲电解液中的对氨基苯酚、苯胺、苯胲及硝基苯的含量。紫外检测器检测波长为254nm，色谱柱为μ-Bondapak C18柱，采用0．05mol/L磷酸二氢钾缓冲液(pH3．5) 甲醇(70 30)为流动相，其流速为1．0mL/min，柱温为室温，对样品进行分析。求出待测组分对氨基苯酚，苯胺，苯胲及硝基苯的回归方程分别为，y=12．75x 0．60，y=2．84x-1．38,y=10．14x 4．33，y=37．46x 3．71，其相应的相关系数依次为0．9995，0．9992，0．9980，0．9981。上述待测组分对内标的相对校正因子分别为2．416，2．176，0．5453，0．1624。     

双波长分光光度-K系数法同时测定荷花玉兰花叶中三种黄酮成分

应用双波长分光光度K系数法测定了荷花玉兰花叶中主要黄酮类成分芦丁、槲皮素和山萘酚.选择297 nm/293 nm,381 nm/397 am,428 nm/451 mn为分析波长对,三种组分的线性范围分别为0.635～12.7,0.576～11.5,0.456～9.12 mg·L-1;样品测定结果的相对标准偏差(n=5)分别为0.1%,0.9%,2.1%;样品加标回收率分别为103.0%,98.4%,97.7%.     

固相萃取液相色谱编程荧光法测定水质中的4-氟苯胺和联苯胺

建立了固相萃取-液相色谱编程荧光法同时测定水中4-氟苯胺和联苯胺的分析方法。采用Cleanert-PCX阳离子交换固相萃取柱富集水中的4-氟苯胺和联苯胺,用5%氨水-甲醇洗脱,以乙腈-水(内含10 mmol/L的乙酸铵溶液)(20/80,V/V)为流动相,采用液相色谱荧光检测器(4-氟苯胺λex/λem=286 nm/354 nm,联苯胺λex/λem=292 nm/395 nm)分析。4-氟苯胺和联苯胺在2.0~200μg/L和1.0~100μg/L范围内,相关系数均大于0.999,方法检出限分别为0.02μg/L和0.01μg/L。在3个浓度水平加标的平均回收率为75.2%~104%,相对标准偏差在2.1%~7.6%之间。     

胶束增敏荷移分光光度法测定水中苯胺

用分光光度法研究了苯胺作为电子给体与电子受体茜素红的荷移反应。在pH 5.0乙酸介质中,苯胺与茜素红可形成1∶1的稳定荷移络合物,加入适量的十二烷基硫酸钠,可引起该络合物的吸光度显著增加,最大吸收波长为525 nm,表观摩尔吸光率为3.25×103L.mol-1.cm-1,苯胺的质量浓度在2.0～56.0 mg.L-1范围内呈线性关系。应用此法测定废水样中微量苯胺,并以此水样为基体作回收试验,测得平均回收率在100.3%。     

高效液相色谱-荧光检测法测定环境水中的苯胺和苯酚

建立了用高效液相色谱荧光检测法同时测定环境水中苯胺和苯酚的分析方法。色谱柱为EclipseXDB C8(4.6mmi.d.×150mm,5μm),流动相为甲醇 磷酸盐缓冲液(0.1mol/L磷酸二氢钾 0 1mol/L磷酸氢二钠,pH6.87)V(甲醇)∶V(磷酸盐缓冲液)=50∶50,流速1 0mL/min,柱温25℃,检测波长0minλex/λem=230/340nm(测定苯胺),3.5minλex/λem=215/300nm(测定苯酚)。测定苯胺的线性范围0.2～120ng,r=0.9999,检出限0.01ng;测定苯酚的线性范围0.4～500ng,r=0.9998,检出限0.02ng,回收率98.1%～101.2%。该方法已用于对环境水中苯胺和苯酚的测定。     

Solvent shift of the ionization potential of the aniline-argon system

The resonant two-photon two-color ionization technique has been used to ionize the Aniline molecule and its Van der Waals complexes with rare gases formed in a supersonic free jet. By scanning the ionizing photon energy, ionization threshold have been determined for Aniline and its first two Van der Waals complexes with Argon. The Ar₁ complex has an ionization energy 96 cm^?1 lower than bare Aniline and the Ar₂ complex has an ionization energy 98 cm^?1 lower than the Ar₁ complex (194 cm^?1 lower than bare Aniline). An interesting correlation has been found between the first Ar-complex solvent shift of the IP for a series of aromatic-argon Van der Waals complexes and the IP of the bare molecule. A simple theoretical model is proposed to discuss the observed correlation.     

A glassy carbon electrode modified with a polyaniline doped with silicotungstic acid and carbon nanotubes for the sensitive amperometric determination of ascorbic acid

We report on an electrochemical sensor for the sensitive amperometric determination of ascorbic acid (AA). Aniline containing suspended silicotungstic acid and carbon nanotubes was electropolymerized on the surface of a glassy carbon electrode in a single step which provides a simple and controllable method and greatly improves the electrocatalytic oxidation of AA. The effects of scan rate, solution pH and working potential were studied. A linear relationship exists between the current measured and the concentration of AA in the range from 1 μM to 10 μM and 0.01 mM to 9 mM, with a limit of detection as low as 0.51 μM (S/N?=?3). The sensor is selective, stable and satisfyingly reliable in real sample experiments. In our eyes, it has a large potential for practical applications.

Liquid chromatographic determination of aniline in table-top sweeteners based on pre-column derivatization with 1,2-naphthoquinone-4-sulfonate

A liquid chromatographic method for the determination of aniline in cyclamate sweeteners based on a pre-column derivatization with 1,2-naphthoquinone-4-sulfonate (NQS) is proposed. Aniline traces were extracted from the cyclamate samples using dichloromethane. After solvent evaporation, the dry residue was derivatized with NQS at pH 9.5 and 85 degrees C for 1 min. The aniline derivative, which was extracted from the reacting mixture, was redissolved in the eluent solution and injected into the chromatographic system. The separation of aniline derivative from other amine impurities was carried out in a C18 column using a 2% acetic acid-methanol (40:60, v/v) mobile phase. Results from the analysis of aniline in the sweetener samples with the proposed method were compared with those from the standard method. A good concordance between the two methods was observed.     

Electrochemical amination of benzene in aqueous-acetic solutions of sulfuric acid

Indirect cathodic amination of benzene with hydroxylamine in the presence of Ti(IV)/Ti(III) mediator system in aqueous media containing 4–11 mol/L H₂SO₄ and 13–5.5 mol/L AcOH has been studied. Aniline, diphenyl, and isomeric phenylenediamines are the electrolysis products at 25–60°C. The increase in temperature favors the formation of the monoamino compound. Aniline yield with respect to hydroxylamine at complete conversion of the latter has reached 78.7%, mass fraction of aniline being 97.1%.     

Formation rates and protonation constants of azo dyes in a sodium dodecylsulphate micellar solution

The effects of a sodium dodecylsulphate micellar solution on the coupling rates of several diazotizated arylamines with N-(1-naphthyl)-ethylenediamine and the shifts in the protonation constants of the corresponding azo dyes are quantitatively studied. Aniline, o-, m- and p-aminobenzoic acids, ethyl p-aminobenzoate and several sulphadrugs are used, and the relationships among the intensity of the effects and the molecular structure of the diazonium ions and the dyes are discussed. A single simplified procedure for the determination of all the substances at pH = 1.3 +/- 0.3, where coupling is quickly completed to directly produce the protonated form of the dyes, is established and applied to the analysis of several pharmaceutical preparations.     

Radiation‐induced conductance in the blends of poly(aniline‐base) with poly(vinyl chloride) and poly[(vinylidene chloride)‐co‐(vinyl acetate)]

In this study blends of Poly(Aniline‐Base)/Poly(Vinylidene Chloride) co‐(Vinyl Acetate) were exposed to radiation to increase the conductance of Poly(Aniline‐Base). Aniline was polymerized by following the procedure of Focke's chemical oxidation method and Poly(vinyl acetate/poly(vinylidene chloride), (PVAc/PVnCl), copolymer was synthesized by solution polymerization Various Poly(Aniline‐Base)/Poly(Vinylidene Chloride) co‐(Vinyl Acetate) films were prepared which were then exposed to gamma rays. The change in the structure was investigated by FT‐IR and UV‐visible spectorphotometer.     

The Phosporylation of Aniline Derivatives in Biphase Systems

Aniline derivatives were phosphorylated in biphase systems using three methods. A comparative study was performed. The best results were obtained when a solid–liquid system was used. This method is the easiest and lead to higher yields (54–81%).     

Validation of a real-time monitoring method for aniline in freshwater by high-performance liquid chromatography on porous graphitic carbon/electrospray ionization tandem mass spectrometry

Aniline is an anthropogenic organic compound widely used in polymer, rubber, pharmaceutical and dye industries but also used in biodegradability assays of chemical compounds as a positive biodegradation standard. By the two approaches, the rapid determination of aniline is necessary because of the high toxicity of aniline on hemoglobin. A high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) method for the determination of aniline in water is described here. This method, using benzylamine as internal standard, was validated. No time-consuming sample preparation was needed. A rapid separation (7 min between two chromatographic runs) of aniline and benzylamine was performed on a Hypercarb porous graphitic carbon column using a gradient of methanol and 100 mM formic acid. The obtained limits of detection and quantification were 10 and 1 ng/mL, respectively. The response for aniline was quadratic. We show that this problem could be circumvented by showing that the [calculated concentration = f(introduced concentration)] function was linear. The linearity range was 10-1000 ng/mL. An example of an application consisting of an aniline 42-day degradation kinetic in water was demonstrated.     

Development of an optode membrane for high pH values

The development of an optical pH sensor for high pH values is described based on the immobilization of Aniline Blue on an optically transparent triacetylcellulose membrane. The membrane is useful for repetitive and reversible pH measurements in the pH range of 8.8-13. The relative standard deviation is about 1.6% and 2% for seven measurements of the maximum change at 579 nm from pH 9 to 10.8 and from pH 11.1 to 12.8, respectively. Other advantages of the sensor include rapid equilibration time, long term stability, reversibility, high sensitivity, freedom from interference of other cations and ease of fabrication.     

液相色谱-串联质谱法快速测定水及鱼肉中的苯胺

为快速准确测定水及鱼肉中的苯胺,采用乙腈提取、高效液相色谱-串联质谱测定,建立了水及鱼肉中苯胺的快速测定方法。水样与乙腈以4：1的体积比混合,1.00 g鱼肉中加入2.00 mL乙腈,涡旋提取1 min,水样和鱼肉样品的提取液离心5 min后取上清液测定。以C₁₈柱为分离柱,乙腈-0.5%（v/v）甲酸水溶液（85：15,v/v）为流动相,目标物质在3 min内分离。在0.5~500 μg/L范围内,苯胺峰面积与内标峰面积之比与质量浓度的线性关系良好（R²>0.999）。基质加标试验结果表明,苯胺在水中的回收率分别为93.7%（加标水平为40 ng）和86.7% （加标水平为400 ng）,苯胺在鱼肉中的回收率分别为96.8%、 92.6%和81.8%（加标水平分别为5、50和500 ng）,相对标准偏差在1.5%~9.2%之间。水样和鱼肉样品中苯胺的检出限分别为0.50 μg/L和1.00 μg/kg,定量限分别为1.00 μg/L和2.00 μg/kg。应用该方法测定了从受苯胺污染的水库中采集的13份水样和12份鱼肉样品,结果表明,水和鱼肉中苯胺的最大含量分别为1943.6 μg/L和60.8 μg/kg。本方法快速、准确,适用于水和鱼肉中苯胺的快速测定。