石墨炉原子吸收法测定水样中的痕量锌

文章对锌含量在μg·mL~(-1)～mg·L~(-1)范围的水样品的石墨炉原子吸收法测定进行了研究。通常由于在石墨炉原子吸收法测定中,由于锌的灵敏度很高使制样过程易受到污染,而火焰原子吸收法测定需较繁杂的富集。通过在样品加入乙醇降低空白值和改进精密度,调节仪器条件的内气流为0.5L·min~(-1)以降低锌的灵敏度,使方法线性范围达到0～20μg·L~(-1)。本法相对标准偏差为0.5％～5.9％之间,检测限为0.098μg·L~(-1)。应用于天然河水、自来水及瓶装矿泉水中锌的测定,结果令人满意。     

催化动力学光度法测定痕量铁

论文研究和建立了催化动力学褪色光度法测定痕量Fe(Ⅲ)的新体系,反应介质为盐酸-邻苯二甲酸氢钾(pH2.2)缓冲溶液,催化体系为痕量Fe(Ⅲ)催化过硫酸铵氧化邻甲氧基酚的自聚反应。研究了此反应体系的最佳条件、动力学参数及反应机理,考察了21种干扰离子的影响,建立了一种新型催化动力学光度法测定痕量Fe(Ⅲ)的方法。本法的线性范围0.07～1.1μg·(25mL)~(-1)。方法灵敏度远远高于普通光度法,检出限为5.4×10~(-8)g·L~(-1)。方法应用于自来水、河水、城市污水、豆奶粉和茶叶中痕量Fe(Ⅲ)的测定,相对标准偏差为0.36％～3.4％,标准加入回收率为97.3％～102.7％,结果满意。     

茶叶中单宁的荧光动力学分析法研究

本文根据在Britton-Robinson缓冲溶液中单宁对Cu(Ⅱ)催化过氧化氢氧化吡咯红Y具有活化作用,使体系荧光狡灭,建立了一个高灵敏度荧光动力学测定痕量单宁的新方法。详细研究了体系的最佳实验条件,采用固定时间法测定体系的荧光强度。该方法的线性范围为0.06～0.96mg·L~(-1),检出限为0.032mg·L~(-1)。对含量为0.32mg·L~(-1)的单宁标准溶液进行11次平行测定,其相对标准偏差为2.3％。将方法用于茶叶中单宁含量的测定,并与Folin-Ciocalteu光度法作了对照,结果满意。     

甲磺酸培氟沙星-La(Ⅲ)络合物的荧光特性研究及应用

在pH 5 6的乙酸 乙酸钠缓冲溶液中 ,La3 与甲磺酸培氟沙星形成络合物。该络合物的荧光强度是甲磺酸培氟沙星的 1 5倍 ,最佳激发波长与最佳发射波长分别为 2 76和 4 4 0nm ,线性范围为 0 0 4～ 2 0mg·L-1,测定下限为 2 8μg·L-1。该体系的抗干扰能力与稳定性较好 ,成功地用于直接测定人血清中甲磺酸培氟沙星含量 ,测定结果为 :含量 4 79mg·L-1,RSD 6 3% ,回收率 95 %。本法亦用于测定胶囊中甲磺酸培氟沙星含量 ,测定结果与紫外 可见光度法一致     

高压消解-原子荧光光谱法同时测定豆科6种中药材中的砷和汞

采用HNO3+ HC1预消解、HNO3+ H2O2高压消解,硫脲-抗坏血酸预还原等手段,建立了高压消解-双道氢化物发生-原子荧光光谱同时测定豆科中药材中砷和汞含量的分析方法.讨论并优化了分析测定条件,结果表明:砷和汞的线性范围分别为0-150、0-90.0ng·mL-1,相关系数分别为0.9992、0.9981,检出限分别是0.0879ng ·mL-1和0.012ng·mL-1;相对标准偏差(n=6)砷不大于5.17％,汞不大于5.14％.应用于豆科6种中药材砷和汞含量的测定,该方法操作性强、用时短、灵敏度高.     

萃取动力学光度法测定活化剂1,10-菲咯啉

研究了在pH值为6.5的NaH_2PO_4-Na_2HPO_4缓冲介质中,利用1,10-菲咯啉活化铜(Ⅱ)催化过氧化氢氧化邻氨基酚显色的指示反应,用萃取平衡控制反应时间和水相中邻氨基酚的浓度及反应程度,通过测量424nm下有机相的吸光度,建立了萃取动力学光度法测定活化剂1,10-菲咯啉的新方法,方法的线性范围为2.00×10~(-8)～6.00×10~(-6)mol·L~(-1)和6.00×10~(-6)～1.25×10~(-5)mol·L~(-1),检出限为6.2×10~(-9)mol·L~(-1)。用于水中1,10-菲咯啉稳定性的测定,结果满意。     

以酚藏花红为指示剂催化荧光法测定痕量钒的研究

基于在硫酸介质中,柠檬酸能活化痕量钒催化溴酸钾氧化酚藏花红的反应,使其荧光减弱,建立了催化荧光法测定痕量钒的新方法。催化反应在沸水浴中进行10min,为假一级反应,该方法的检出限为0.26μg·L~(-1),测钒的线性范围为0.6～3.2μg·L~(-1),研究了共存离子的影响。该方法用于水样及人发中痕量钒的测定,结果满意。     

流动注射化学发光法测定诺氟沙星

在酸性条件下,Ce(Ⅳ)与诺氟沙星(NFLX)能产生弱的化学发光反应,十二烷基硫酸钠(SDS)对其有较强的增敏作用。据此建立了一种简单、快速、可连续测定诺氟沙星的流动注射化学发光新方法。该法线性范围7.78×10-8～5.82×10-6 g·mL-1 ,检测限(3σ)为1.57×10-8 g·mL-1,对1.94×10-6 g·mL-1 的NFLX标准溶液平行测定10次,相对标准偏差为1.7%。该法成功应用于诺氟沙星胶囊的测定, 还对其机理进行了初步探讨。     

培氟沙星胶束包合物的荧光特性及应用

提出一种基于胶束增敏测定培氟沙星的荧光分光光度法 ,研究了培氟沙星与十二烷基硫酸钠 (SDS)形成胶束包合物的荧光性质 ,对影响荧光的不同变量和参数进行了研究和优选。试验结果表明 ,在pH 5的BrittonRobinson(BR)缓冲溶液中 ,SDS胶束对培氟沙星有强的增敏作用 ,培氟沙星胶束包合物的激发和发射波长分别为 λex =2 78nm和λem =4 32nm 。其线性范围为 0 0 6～ 1 2 0 μg·mL- 1 ,方法检出限为 0 0 6 μg·mL- 1 ,回收率为 98 5 %～ 10 0 8% ,相对标准偏差为 1 4 %～ 2 3%。该方法已成功用于片剂和血浆中培氟沙星含量的测定 ,其结果令人满意。本文采用同步导数荧光光谱法测定了血浆中的培氟沙星 ,其选择性好 ,灵敏度高 ,可有效地消除血浆中荧光背景的干扰 ,降低了检测限。     

偏最小二乘-同步荧光光谱法同时测定鳗鱼组织中三种喹诺酮药物残留量

应用偏最小二乘(PLS)算法对同步荧光光谱严重重叠的诺氟沙星、盐酸洛美沙星和乳酸左氧氟沙星药物三组分混合体系进行波谱解析,建立了该混合体系含量同时测定的新方法。在pH 2.87 B-R缓冲溶液中,波长差Δλ=190 nm 时,诺氟沙星、盐酸洛美沙星和乳酸左氧氟沙星的测量线性范围分别为0.016～0.40 μg·mL-1,0.01～0.336 μg·mL-1和0.01～0.336 μg·mL-1;检出限分别为0.012 6,0.006和0.007 2 μg·mL-1。采用PLS法结合同步荧光法对鳗鱼样品进行测定,结果令人满意。     

喹诺酮类药物的质子化作用及互变异构现象与荧光特性的相关性研揪

研究了不同酸碱条件下8种喹诺酮类药物的荧光特性.发现了在不同pH介质中喹诺酮类药物的荧光波长和荧光强度的变化规律,并对喹诺酮类药物质子化作用及互变异构现象与荧光性质的相关性进行了考察.确定了不同酸碱条件下的两种发光形体,进而对相应的变化机理进行了探讨.     

喹诺酮类药物的质子化作用及互变异构现象与荧光特性的相关性研究

研究了不同酸碱条件下8种喹诺酮类药物的荧光特性,发现了在不同PH介质中喹诺酮类药物的荧光波长和荧光强度的变化规律,并对喹诺酮类药物质子化作用及互变异构现象与荧光性质的相关性进行了考察,确定了不同酸碱条件下的两种发光形体,进而对相应的变化机理进行了探讨。     

Characterization and pH stability of insoluble products of the reaction between cyanide and ferrous sulphate

X-ray diffraction (XRD), infrared (IR) spectroscopy and⁵⁷Fe Mössbauer effect spectroscopy were used to characterize and monitor the pH stability of cyanide and ferrous sulphate reaction mixtures. Limited information was obtained from the XRD and IR measurements because of the amorphous nature of the samples. The Mössbauer studies show that considerable changes occur when there is an increase in pH at which the sample is prepared. Prussian-blue type compounds and iron oxide in the form of small particles crystallize out at low and high pH values, while additional complexes are formed at intermediate pH values of 6 to 9.⁵⁷Fe Mössbauer effect spectroscopy is thus a powerful technique for monitoring the environmental stability of cyanide waste streams that result when modern methods of extractive metallurgy of gold are employed on mineral ores.     

Correlation between photophysical properties and lasing performances of Rhodamine-19 in three types of sol–gel glass hosts

Rhodamine-19 (Rh-19) incorporated three types of sol–gel samples (mentioned as dope route-I, dope route-II and dip method) were prepared by using two different methods of dye impregnation. The photophysical properties of all the three types of Rh-19 incorporated sol–gel solids were studied by using the UV–Visible absorption and the fluorescence spectroscopy. A single photon counting technique was used to estimate the lifetime of fluorescent species. From the study of fluorescence spectra, the coexistence of dimers (fluorescent and non-fluorescent both) and monomer of Rh-19 was observed. The photophysical properties of Rh-19 were found to be the best in dip sample, medium in dope route-II sample and low in dope route-I sample. After studying photophysical properties, the samples were subjected to laser study under nitrogen laser pumping at 337.1 nm at the rate of 1.5 Hz in transverse dye laser cavity. The highest laser efficiency and photostability of the dye were observed in dip sample, medium in dope route-II sample and small in dope route-I sample. A comparison between photophysical properties and laser performance of these materials showed a very good correlation.     

Thermo-Sensitivity of poly-N-isopropylacrylamide with Statistically Introduced D,L-Allylglycine Betainic Units

Abstract

Statistical copolymers of N-isopropylacrylamide containing 2.2 – 2.7?mol % D,L-allylglycine were synthesized. The sample with 2.2?mol % allylglycine and molar mass 320000?g/mol was studied using light scattering and turbidimetry while heated in water and water–salt solutions. Temperature dependencies of light scattering intensity and optical transmission as well as hydrodynamic size and composition of the scattering entities were obtained in a wide range of pH. The onset temperatures of phase separation were independent of pH; however, in the basic pH region the phase transition was widened as compared to the neutral and acid media. It was shown that a small content of allylglycine results in a different thermoresponsive behavior of the copolymer as compared with N-isopropylacrylamide homopolymer. The addition of a physiological amount of NaCl shifts the copolymer thermo-sensitivity toward lower temperatures.     

螯合棉纤维预富集流动注射在线测定痕量铅

将自制的性能优越、成本低廉的新型吡咯烷二硫代甲酸铵螯合棉纤维(CC-APDC)作为固相富集材料,经稀硝酸洗脱液的流动注射预富集, 用石墨炉原子吸收光谱测定了痕量铅。流动注射预富集分六步完成。用稀硝酸作洗脱液,完全洗脱需0.15 mL,大大超过石墨管进样体积。实验将洗脱的前40 μL定量弃去,采用定体积取样法,将浓度最高的40 μL洗脱液加入GFAAS中,提高了测定的准确度。另外在石墨炉灰化阶段高记忆效应的消除中,将惯用的停气方式改为小流量(30 mL·min-1,富集1 min)气体原子化,使拖尾现象得到了明显的改善,且空白值低而稳定。考察了实验参数,如酸度,洗脱液浓度,洗脱速度及采样速率等)对分析性能的影响。采用螯合棉纤维作分离富集材料,选择性好,方法灵敏度高,可以在线分离干扰,采样速度50次·h-1。富集倍数15倍,检测下限0.2 μg·L-1,相对标准偏差1.4%(n=10),回收率95%～105%,样品测定结果令人满意。     

Induction heating studies of magnetite nanospheres synthesized at room temperature for magnetic hyperthermia

An investigation of the synthesis of Fe₃O₄ nanopowders by the co-precipitation method is reported from aqueous and ethanol mediums. X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer are utilized to study the effect of variation of synthesis conditions on the crystal structure, crystallite size, microstructure and magnetic properties of the formed powders. The XRD analysis showed that the crystalline Fe₃O₄ phase was formed at Fe³⁺/Fe²⁺ molar ratio 2.0 prepared at room temperature for 1 h at pH 10. The crystallite size was in the range between 8 and 11 nm. TEM micrographs showed that the particles appeared as nanospheres. Superparamagnetic nanoparticles with low coercivity and remanence magnetization were achieved. Heating properties of the nanosphere samples in an alternating magnetic field at 160 KHz were evaluated. An excellent heating efficiency for the sample prepared in ethanol medium is a result of more relaxation losses occurring due to its small particle size.     

Influence of synthesis conditions on structural,optical and magnetic properties of iron oxide nanoparticles prepared by hydrothermal method

The iron oxide nanoparticles were synthesized by a simple hydrothermal method at different heating temperatures and pH conditions. The synthesized materials were characterized by X-ray diffractometer, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, UV–visible spectrometer and vibrating sample magnetometer. With increment in pH of the synthesized materials were resulted in orthorhombic (goethite) and cubic (magnetite) structures at pH 6 and 12, respectively. The banding nature of synthesized materials was analyzed by infrared spectra. The synthesized powders at 130?°C showed higher percent of nanorods (length = 90–120 nm) in addition to lower percentage of nanoparticles. The material at pH 12 consisted of maximum nanoparticles with size = 10–60 nm with small agglomerations. Band gap energy of synthesized materials was 2.2–2.8 eV. Herein, the reaction conditions tuned the saturation magnetization (M_S). The maximum M_S (59.38 emu/g) was obtained at pH 12 and lower M_S (0.65 emu/g) was observed at pH 6 due to intrinsic property of goethite phase.     

铁皮石斛品质影响因素快速无损检测及光谱特性分析

随着人民生活水平的提高,中草药的保健功能越来越得到大家的重视,铁皮石斛是我国名贵中药材,素有“救命仙草”之称。尝试用叶绿素、糖度和pH值作为铁皮石斛的品质指标,选择安徽霍山、浙江雁荡山和云南3个不同产地的铁皮石斛作为研究对象,提取不同铁皮石斛的光谱数据和理化参数,然后进行各品质指标的反演,最终建立品质指标与光谱之间的相关模型,并对模型的有效性进行分析。实验中的研究对象是铁皮石斛的茎,用ASD光谱仪得到三种铁皮石斛茎的光谱数据,再把同一批样本研磨碎,放入离心管中加入甲醇溶液密封,并用锡箔纸包装处理制成相应的溶液,采用分光光度计、糖度计和pH计测量叶绿素含量、糖度和pH值,每个样本分别选取离心试管中的上层,中层,下层溶液检测糖度,测量3次并取平均值,以此结果作为对照组。原始光谱数据通过小波变换去除噪声和降维,将得到的能量系数（包括波段与尺度）,与铁皮石斛对照组的理化参数进行相关性分析,选取决定系数中较高的能量系数作为小波特征,用最小化二乘法对小波特征拟合。用全部实验样本作为测试集,随机选取70%作为验证集,对于浙江雁荡山、安徽霍山和云南三种不同品种铁皮石斛：叶绿素含量反演模型的决定系数（R2）分别为0.819,0.820和0.865,均方根误差（RMSE）分别为为0.035,0.013和0.017;糖度反演模型的决定系数（R2）分别为0.756,0.764和0.823,均方根误差（RMSE）分别为0.025,0.030和0.0368;pH值的反演模型决定系数（R2）分别为0.819,0.820和0.865,均方根误差（RMSE）分别为0.0345,0.013和0.017。从中可以发现,三种不同铁皮石斛的品质反演模型和决定系数（R2）均大于0.80,均方根误差（RMSE）小于0.10。实验证明了铁皮石斛中叶绿素、糖度和pH值的光谱特性对其进行品质评估的可行性。     

Contribution of electrolyte pH and deposition potentials to the magnetic anisotropy of electrodeposited nickel films

The influence of electrolyte pH and cathode potential on the magnetic properties of single layer Nickel films electrodeposited on polycrystalline titanium substrates was studied. The films were deposited at the electrolyte pH=3.5±0.1, 2.5±0.1 and 2.1±0.1 by varying the deposition potentials (?1.2, ?1.5 and ?1.8 V vs saturated calomel electrode, SCE) applied in continuous waveform. The structural analysis by X-ray diffraction revealed that the films have face-centred cubic structure. Results of the magnetic measurements obtained by vibrating sample magnetometer (VSM) indicated that the magnetic properties were affected by the electrolyte pH and the cathode potentials in terms of magnetic anisotropy. At the highest pH the films deposited at the lowest potential had in-plane magnetic anisotropy. As the electrolyte pH decreased from the high (pH=3.5±0.1) to low (pH=2.5±0.1), which is aided by increasing the potentials, resulted in an almost magnetic isotropy in the films. However, isotropic magnetic behaviour was observed for the film deposited at the low pH combined with the high potential (?1.8 V vs SCE). Magnetic thickness profile of the samples obtained by VSM revealed that the isotropic films have a smoother magnetic variation across the film from one edge than the anisotropic ones. This is also verified with a microscopic observation by an optical microscope and the surface of the isotropic films is observed to be smoother than that of the anisotropic ones. Furthermore, all films were found to have planar magnetic anisotropy irrespective of the pH’s and the potentials.