Synthesis and characterisation of the Fe(II–III) hydroxy-formate green rust

A new methodology was envisioned in order to prepare green rust compounds build on organic anions that could intervene in microbiologically influenced corrosion processes of iron and steel. The formate ion was chosen as an example. The formation of rust was simulated by the oxidation of aqueous suspensions of Fe(OH)₂ precipitated from Fe(II) lactate and sodium hydroxide, in the presence of sodium formate to promote the formation of the corresponding green rust. The evolution of the precipitate with time was followed by transmission Mössbauer spectroscopy at 15 K. It was observed that the initial hydroxide was transformed into a new GR compound. Its spectrum is composed of three quadrupole doublets, D ₁ (δ?=?1.28 mm s^?1, Δ?=?2.75 mm s^?1) and D ₂ (δ?=?1.28 mm s^?1, Δ?=?2.48 mm s^?1) that correspond to Fe(II) and D ₃ (δ?=?0.49 mm s^?1, Δ?=?0.37 mm s^?1) that corresponds to Fe(III). The relative area of D ₃, close to the proportion of Fe(III) in the GR, was found at 28.5?±?1.5% (～2/7). Raman spectroscopy confirmed that the intermediate compound was a Fe(II–III) hydroxy-formate, GR(HCOO^?).     

Simultaneous determination of ethyl carbamate and 4‐(5‐)methylimidazole in yellow rice wine and soy sauce by gas chromatography with mass spectrometry

We developed a new method, based on alkaline diatomite solid‐phase extraction followed by gas chromatography with mass spectrometry, for the simultaneous determination of the toxic contaminants ethyl carbamate (EC) and 4‐(5‐)methylimidazole (4‐MEI) in yellow rice wine and soy sauce. The optimal extraction conditions were defined. With the application of alkaline diatomite solid‐phase extraction, damage to the capillary column by organic acids was greatly reduced. With deuterated EC used as the internal standard, the linearity of the calibration curves for EC and 4‐MEI was good with correlation coefficient above 0.99. In a spiked experiment with EC and 4‐MEI in yellow rice wine and soy sauce, recovery of the added EC was 80.5–102.5% and that of 4‐MEI was 78.3–92.8%. The limit of quantification and limit of detection for EC were 6.0 and 2.0 μg/kg, respectively, and for 4‐MEI were 15.0 and 5.0 μg/kg, respectively. The validation results demonstrate that the method is fast, simple, and selective, and therefore is suitable for simultaneously determining the presence of EC and 4‐MEI in fermented food.     

Chromonic liquid crystals formed by CI Acid Red 266 and related structures

Chromonic liquid crystals are currently receiving increased attention because they have applications in a wide range of products. In this study, we have compared the chromonic mesophase behaviour of four azo dyes with similar chemical structures. Our objective is to determine if there is an obvious link between mesophase formation and dye chemical structure. Orange G does not form mesophases over the concentration range examined (saturated solution > ~20–30 wt%). The other three compounds all form nematic (N) and hexagonal (H) mesophases, but over very different concentration ranges. X-ray diffraction shows that the ordered Edicol Sunset Yellow (ESY) aggregates present in the mesophases have a single molecule cross section, while those of CI Acid Red have a cross section equivalent to six to eight molecules, probably organised in a ‘water-filled pipes’ structure. NMR quadrupole splittings of ²H₂O demonstrate that water binding to the aggregates is similar to that found for surfactant lyotropic mesophases. The sodium (²³Na) quadrupole splittings for Orange II and CI Acid Red are similar to the values found for surfactant hexagonal phases, suggesting that most sodium ions are ‘bound’ to the aggregates. This is unlike the behaviour of ESY where only one of the two sodium ions is bound.     

胶州湾表层沉积物重金属分布特征及污染评价

为评价胶州湾跨海大桥的建设对其沉积物中重金属分布的影响,于2009年7月采集了黄海胶州湾11个站位的表层沉积物,测定了沉积物中的重金属含量.结果显示,胶州湾沉积物重金属污染程度较低,Hg、Cu、Pb、Zn、Cd、Ni、Co、Mn 8种重金属的平均含量分别为0.031、19.05、12.7、51.14、0.055、17....     

Application of Glassy Carbon Electrode Modified with a Bilayer of Multiwalled Carbon Nanotube and Polypyrrole Doped with Nitrazine Yellow for Voltammetric Determination of Naltrexone

A new sensitive electrochemical sensor was fabricated based on a layer by layer process. In this process the glassy carbon electrode (GCE) is first coated by a thin film of multiwalled carbon nanotubes (MWCNTs). In the next step, the electropolymerization of pyrrole in the presence of Nitrazine Yellow (NY) as a dopant anion is performed on the surface of the MWCNTs precoated electrode. The electrochemical response characteristics of the modified electrode toward naltrexone (NTX) were studied by means of linear sweep voltammetry (LSV). A remarkable increase (～19 times) was observed in the anodic peak current of NTX on the surface of the modified electrode relative to the bare GCE. The effects of experimental parameters on the electrode response such as, drop size of the cast MWCNTs suspension, pH of the supporting electrolyte, accumulation conditions and the number of cycles in the electropolymerization process were investigated. Under the optimum conditions, the modified electrode showed a wide linear response to the concentration of NTX in the range of 4.0×10^?8–1×10^?5 mol L^?1 with a detection limit of 12 nmol L^?1. The prepared sensor exhibited high sensitivity, stability and good reproducibility for the determination of NTX. This sensor was successfully applied for the accurate determination of trace amounts of NTX in pharmaceutical and clinical preparations.     

微波消解-ICP-OES测定青海野生黄蘑菇中的矿质元素

经湿法微波消解制样,利用全谱直读电感耦合等离子体-发射光谱法（ICP-OES）对青海野生黄蘑菇中的矿质元素进行全面详细的分析测定。测定结果表明,野生黄蘑菇中含有K、P、S、Mg、Ca、Fe、Al、Na、Zn、Cu、Mn、Cd、Ti、B、Ba、Cr、Sr 17种矿质元素,常量矿质元素中K、P、S的含量较高,微量元素中,Fe、Zn和Cu含量丰富,同时含有一定量的Cd元素,未检出Se元素。分析方法回收率在92.2%—108.8%之间,RSD为0.79%—9.05%。该方法简单、快速、可靠、灵敏度高,且多元素可同时测定,能满足实际样品分析要求。分析结果可为青海野生黄蘑菇的开发利用研究提供参考。     

吖啶黄催化动力学光度法测定纺织品中的微量甲醛

在硫酸介质中,甲醛能灵敏地催化溴酸钾氧化吖啶黄褪色,据此建立了一种测定甲醛的催化动力学光度法.在5.0-150.0μg/L范围内,△A与甲醛的浓度呈良好的线性关系,线性方程为△A=0.0292+0.0084C(μg/L),检出限为0.57μg/L.用于纺织品中甲醛的测定,相对标准偏差小于4.50%,加标回收率为96.6...     

纳米TiO2光催化氧化活性嫩黄废水

以TiCl4为原料,采用可控水解法制备了TiO2光催化剂。以活性嫩黄为模拟污染源,紫外灯为光源,考察了溶液pH值、催化剂用量、反应时间和催化剂循环次数等对纳米二氧化钛光催化降解活性嫩黄的影响。实验结果表明,pH 5.5,催化剂投加量为2.0g/L,光催化反应时间为60min时,色度及化学需氧量（COD）去除率均较高。TiO2光催化剂重复使用在5次以内,其催化活性基本不变。     

基于近红外光谱技术的小麦条锈病菌潜伏侵染的检测

为实现对受到小麦条锈病菌侵染而尚未表现明显症状的小麦叶片进行早期检测,利用近红外光谱技术结合定性偏最小二乘法建立了小麦条锈病潜育期叶片定性识别模型。获取健康叶片30片、条锈病潜育期叶片330片(每天取30片,共11天)和发病叶片30片,扫描获得其近红外光谱曲线。采用内部交叉验证法建模,研究了不同谱区、建模比(建模集∶检验集)、光谱预处理方法和主成分数对建模识别效果的影响。在5 400~6 600和7 600~8 900cm-1组合谱区内,建模比为4∶1、预处理方法为"散射校正"和主成分数为14时,所建模型识别效果较理想,建模集的识别准确率、错误率和混淆率分别为95.51%,1.28%和3.21%;检验集的识别准确率、错误率和混淆率分别为100.00%,0.00%和0.00%。结果表明,利用近红外光谱技术可在接种1天后(即提前11天)识别出健康小麦叶片和受到条锈病菌侵染的小麦叶片,并且可以识别不同潜育期天数的叶片。因此,利用近红外光谱技术对条锈病菌潜伏侵染检测是可行的,为该病早期诊断提供了一种新途径。     

分光光度法测定3种颜色桑葚中的总多酚

桑葚含有丰富的多酚类化合物(含量因部位不同而有差异),这类化合物具有抗动脉硬化、降低胆固醇、抗氧化和抗辐射等作用,可用来有效地评价桑葚的活性.采用Folin-Ciocalteu法对桑葚中的总多酚进行检测.以没食子酸为对照品,校准曲线的回归方程为y=99.65x+0.02990(r=0.9997);对稳定性、精密度,重现...