Complex samples cyanide detection with immobilized corrinoids

Colorimetric solid phase with spatially separated extraction and detection zones as a rapid, effective and economic method for the optical detection of cyanide in complex samples is described. The system is seven times more sensitive for the optical detection of cyanide than the same class of chemical sensors used under homogeneous conditions. The application of the method in the detection of (i) endogenous cyanide in colored plant samples and of (ii) hydrogen cyanide in tobacco smoke is shown. The optical detection of multiple anions within a single sample has been demonstrated in principle for the detection of both CN(-) and SCN(-). Immobilized aquacyano-corrinoids and immobilized vitamin B12 are applied as chemical sensors, and cyanide is qualitatively identified by the violet color (λ(max) = 583 nm) of the corresponding dicyano-complex. Quantitative determinations with diffuse reflectance spectroscopy (DRUV-vis) are possible in the linear range up to 0.2 mg/L with a LOD of 1 μg/L. Alkyl-modified silica particles are employed for immobilization of the indicator on the surface of the solid phase (detection zone), and for removal of colored hydrophobic interferents (extraction zone).     

Subnanomolar cyanide detection at polyphenol oxidase/clay biosensors

A novel, inexpensive, and simple amperometric biosensor based on immobilization of polyphenol oxidase (PPO) into Zn-Al layered double hydroxides, also called anionic clays, is applied for determination of cyanide. The detection of cyanide was performed via its inhibiting action on the PPO electrode. Measurement was carried out with 3,4-dihydroxyphenylacetic acid as enzyme substrate, the enzymatically generated quinoid products being electroreduced at -0.2 V. An extremely sensitive detection limit (0.1 nM) was obtained for cyanide. Enzyme immobilization into an anionic exchanger clay seems to cause an increase in cyanide inhibition effects because of anion accumulation in the clay matrix.     

Thermoresponsive copolymer containing a coumarin-spiropyran conjugate: reusable fluorescent sensor for cyanide anion detection in water

A simple copolymer consisting of N-isopropylacrylamide and coumarin-conjugated spiropyran (CS) units, poly(NIPAM-co-CS), has been synthesized. This polymer enables selective fluorometric detection of cyanide anion (CN(-)) in water at room temperature. The polymer itself shows almost no fluorescence, but shows a strong blue fluorescence in the presence of CN(-) under irradiation of UV light. The fluorescence enhancement occurs via a nucleophilic interaction between CN(-) and the photoformed merocyanine form of the CS unit, leading to a localization of π-electrons on the coumarin moiety. The polymer enables accurate determination of very low levels of CN(-) (>0.5 μM). The polymer can be recovered from water by simple centrifugation at high temperature (>40 °C), due to the heat-induced aggregation of the polymer. In addition, the polymer is regenerated by simple acid treatment, and the resulting polymer is successfully reused for further CN(-) sensing without loss of sensitivity.     

氰化氢脱除方法

氰化氢(HCN)作为聚丙烯腈基炭纤维(PANCF)及其他产业中产生的一种有害气体,其脱除日益受到人们的重视。通过介绍目前用于脱除HCN的几种主要方法(吸收法、吸附法、直接燃烧法和催化燃烧法)的原理、操作条件及适用对象,比较了各种方法的优缺点。结果表明:催化燃烧法由于具有安全性能好,净化效率高,起燃温度低,节省能源,无二次污染,工艺简单,操作方便等优点,对处理PANCF高温炭化与煤高温裂解产生的HCN具有较大的优势。     

Electrochemical preparation of potassium gold cyanide

The essential requirements for the industrial preparation of potassium gold cyanide (pgc) are: (a) high rate of dissolution and (b) smooth and uniform dissolution. Employing galvanostatic and potentiostatic polarisation data and observations on the surface topography of anodes dissolved by both the techniques, it is shown that potentiostatic dissolution of gold in potassium cyanide at +0·345 V satisfies the above requirements.     

False Interpretations of Point-Recorded Diagrams

A formula is developed giving the exact mathematical expression of the simplest and usual interpretation of a point-recorded diagram, as is obtained by connecting the successive points with straight-line segments. The formula clearly indicates the spectrum of frequencies existing in such a straight-line interpretation. The most significant aspect of this analysis is represented by some low-frequency terms not existing in the recorded signal.     

Segmented flow injection,UV digestion,and amperometric detection for the determination of total cyanide in wastewater treatment plant effluents

The currently approved method for the analysis of total cyanide (TCN) in wastewaters has remained virtually unchanged in the 25 years since its initial use; this despite its subjection to a number of interferences, many of which provide a positive bias in cyanide measurements, including the formation of TCN during sample processing and some of which remain undocumented to this day. In particular, many municipal wastewater treatment plant chlorinated effluents throughout North America have often been cited for permit violations on the levels of total cyanide in their effluents measured using this methodology. A recently developed procedure for the analysis of TCN in various matrixes that utilizes segmented flow injection for sample transport and reaction, on-line acidic UV digestion for conversion of complexed cyanide to HCN, and amperometric detection achieved within 4 min of sample injection is demonstrated on chlorinated effluents discharged from municipal wastewater treatment plants. Through a systematic evaluation of the chemistry of the processes involved in this method and an understanding of the complexity of the wastewater matrix, an application was developed that showed consistent reproducibility in measuring TCN in a variety of effluents. The method was employed initially on synthetic solutions containing controlled levels of constituents identified in the literature as interfering with the measurement of TCN through the traditional distillation/colorimetric approach. In its application to the analysis of TCN in chlorinated wastewaters, an approach was evolved that ensured that dechlorination carried out during sample processing did not bias the results of analysis.     

如何识别变造假币

变造假币即拼凑币，票面一部分是真币，一部分是假币，这类假币比其它假币具有更强的欺骗性。专家提醒人们在收付大面额人民币时，防止误收误付变造假币，要格外注意以下几点：     

谈检验报告的防伪打假

如今，随着全社会质量意识的不断提高，法定检验检测机构出具的检验报告因其具有的公正性、科学性以及具有法律效力日益受到人们的重视。比如，商家在进货时会找厂家索要产品的检验报告，不少有心的顾客在购买产品时也会找商家查验一下产品的检验报告。     

假冒商品横行比利时

每年的1月和7月,是很多欧洲国家的商品打折季节.一些名牌商品纷纷跳水甩卖,甚至以低至五折、四折的价格出售,看得人不禁心动.这两个月成为很多人到欧洲旅游的首选时间,除了气候舒适之外,购物也是一大因素.买到便宜的名牌货品后自然会觉得很开心,但如果有人告诉你这些名牌都是假的,你还高兴得起来吗?这不是在开玩笑,是完全有可能遇到的事情.     

制备氰化亚铜治理高浓度含氰废水

本文研究了制备氰化亚铜法处理高浓度含氰废水工艺及反应机理,并对氰化亚铜法处理高浓度含氰废水的处理方法、处理条件、处理效果进行探讨,得出该处理方法具有设备简单、无需加热、处理能耗低、资源重复利用、消除二次污染等特点。     

Biodegradation of cyanide containing effluents by Scenedesmus obliquus

Biological degradation of cyanide has been shown a viable and robust process for degrading cyanide in mining process wastewaters. Several algal cultures can effectively degrade cyanide as carbon and/or nitrogen source for their growth. In this study, cyanide effluent degradation by Scenedesmus obliquus was examined. Gold mill effluents containing WAD cyanide concentration of 77.9mg/L was fed to batch unit to examine the ability of S. obliquus for degrading cyanide. Cyanide was reduced down to 6mg/L in 77h. Microbial growth and metal uptake of Zn, Fe and Cu was examined during cyanide degradation. The cells well adapted to high pH and the effluent contained cyanide and the metals. It is important that Zn level reduced down 50%, of the starting concentration. pH was kept at 10.3 to prevent loss of cyanide as HCN, due its volatile nature. The bio treatment process was considered to be successful in degrading cyanide in the mine process water.     

Formation of TiN whiskers from oxide-containing cyanide melts

It has been found that the formation of TiN whiskers by reaction of molten alkali metal (sodium, potassium) cyanide with TiN powder or with TiO₂ is effected by the presence of alkali metal oxides. This has led to the successful use of reactions of molten cyanide with several sodium and potassium titanates for the formation of TiN whiskers.     

WTO直视下的虚假包装研究

虚假包装是目前市场流通中不正当竞争的行为。特别是在经济全球化的情况下,市场竞争越来越激烈,很多不法经营者为了获取最大的利润,利用虚假包装成为他们的重要手段。1.虚假包装是一种“包装污染”(1) 虚假包装的目标任何假冒产品都是去假冒那些知名度、信誉度高并且有广阔市场,在消费者心目中有很好形象的名牌产品。例如,著名的湘潭龙牌酱油已有100多年