Applications of aptamers for chemistry analysis, medicine and food security

Since aptamer and its in vitro selection process called SELEX were independently described by Ellington and Gold in 1990, extensive research has been undertaken and numerous isolated aptamers for various targets have been applied. Aptamers can bind to a wide range of targets that include small organic molecules, inorganic compounds, haptens and even whole cells with high binding affinity and specificity. Aptamers for a wide range of targets have been selected currently. In addition, aptamers are thermo stable and can also be regenerated easily within a few minutes denaturation, which makes them easy to store or handle. These advantages make aptamers extremely suitable for applications based on molecular recognition as analytical, diagnostic and therapeutic tools. In this review, the recent applications of aptamers for chemistry analysis, medicine and food security, along with the future trend will be discussed.

Computer Management of Quantitative Analysis Chemistry Experiment

The application of computer in the quantitative analysis chemistry experiment is a chemistry experiment teaching applications software, developed by Visual Basic （6.0）, based on the content of quantitative analysis chemistry experiment of chemistry major in higher institute. This software has the function of the automatic processing the experimental data, the automatic generation of test report copies, and the automatic evaluation of students＇ experimental results, which solve the reliability, objectivity and accuracy problems of the students＇ experiment data processing and evaluation, and avoid interference with human factors. The software has the characteristic of the easy installation, the easy operation, the strong practicability, pertinence, the systematicness and the running stability, so it provides a platform in the quantitative analysis chemistry experiment for the students＇ assessment system of automatic processing, and it has a high popularization value. The project＇s technical route design is reasonable, the research method is correct, and the experimental data processing results are reliable, which has reached the leading domestic level in the quantitative analysis chemistry experiment teaching field of computer data processing. And this project has been through the achievements appraisal of Gansu Provincial Sci. ＆ Tech. Department.

A Heavy Metal Analysis Device Based on Light-addressable Potentiometric Sensor

<正>A full automatic device to detect heavy metal Hg,Fe,Cr elements based on thin-film sensitive materials prepared on surface of light-addressable potentiometric sensors (LAPS) by means of pulsed laser deposition PLD) technique is developed. High-purity chemical compound AgI:Ag_2S:HgI synthesized were used as target of PLD,thin film sensitive to Hg~ (2+) ion was prepared on the surface of LAPS.All-solide-state chalcogenide glass ion-selective electrodes ISE) ,Fe-ISE and Cr-ISE,were also used as targets of PLD,and thin-film sensors on different LAPS sensitive to Fe~ (3+) and Cr~ (6+) ions were prepared.The heavy metal analysis device with characteristics of collect sample in-site,real-time determination,communication and multifunction software were designed.Hardware design of the device mainly includes control and measurement aspects.The detected limits of Hg,Fe,Cr ions are 3.44×10~ (-7) mol/L,6.31×10~ (-6) mol/L and 2.09×10~ (-7) mol/L,respectively.

Hydrogeochemical modelling of corrosive environment contributing to premature failure of anchor bolts in underground coal mines

Anchor bolts are commonly used throughout underground mining and tunnelling operations to improve roof stability.However,premature failures of anchor bolts are significant safety risks in underground excavations around the world due to susceptible bolt materials,a moist and corrosive environment and tensile stress.In this paper,laboratory experiments and hydrogeochemical models were combined to investigate anchor bolt corrosion and failure associated with aqueous environments in underground coal mines.Experimental data and collated mine water chemistry data were used to simulate bolt corrosion reactions with groundwater and rock materials with the PHREEQC code.A series of models quantified reactions involving iron and carbon under aerobic and anaerobic conditions in comparison with ion,pH and pE trends in experimental data.The models showed that corrosion processes are inhibited by some natural environmental factors,because dissolved oxygen would cause more iron from the bolts to oxidize into solution.These interdisciplinary insights into corrosion failure of underground anchor bolts confirm that environmental factors are important contributors to stress corrosion cracking.

4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-1,3,5-triazine modified carbon paste electrode for trace Cu(Ⅱ) determination by differential pulse volt-ammetry

A differential pulse voltammetric method was developed for the sensitive andselective determination of Cu(II) at 4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-l,3,5-triazine modifiedcarbon paste electrode in 0.05 mol/L KHC_8H_4O_4 solution (pH = 4.02). The oxidation peak of Cu(II)was observed at 0.065 V(vs Ag/AgCl) by scanning the potential in positive direction. The analysisprocedure consisted of an open circuit accumulation step in stirred sample solution. It was followedby medium exchange to a clean solution and subsequently an anodic potential scan was affected toobtain the voltammetric peak. The current was proportional to the concentration of the Cu(II) ion ina range of 1 X 10^(-7) -1 X 10^(-4) mol/L for 6 min accumulation; the most of metal ions did notinterfere with the determination. The developed method was applied to Cu (II) determination incoal-ash sample, the results agreed with that of atomic adsorption spectroscopy (AAS).

Methylated and thiolated arsenic species for environmental and health research——A review on synthesis and characterization

Hundreds of millions of people around the world are exposed to elevated concentrations of inorganic and organic arsenic compounds, increasing the risk of a wide range of health effects. Studies of the environmental fate and human health effects of arsenic require authentic arsenic compounds. We summarize here the synthesis and characterization of more than a dozen methylated and thiolated arsenic compounds that are not commercially available. We discuss the methods of synthesis for the following14 trivalent（Ⅲ） and pentavalent（） arsenic compounds： monomethylarsonous acid（MMA~Ⅲ）, dicysteinylmethyldithioarsenite（MMA~Ⅲ（Cys）_2）, monomethylarsonic acid（MMA~Ⅴ）,monomethylmonothioarsonic acid（MMMTAⅤ） or monothio-MMA~Ⅴ, monomethyldithioarsonic acid（MMDTA~Ⅴ） or dithio-MMA~Ⅴ, monomethyltrithioarsonate（MMTTA~Ⅴ） or trithio-MMA~Ⅴ,dimethylarsinous acid（DMA~Ⅲ）, dimethylarsino-glutathione（DMA~Ⅲ（SG））, dimethylarsinic acid（DMA~Ⅴ）, dimethylmonothioarsinic acid（DMMTA~Ⅴ） or monothio-DMAⅤ, dimethyldithioarsinic acid（DMDTA~Ⅴ） or dithio-DMA~Ⅴ, trimethylarsine oxide（TMAO~Ⅴ）, arsenobetaine（AsB）, and an arsenicin-A model compound. We have reviewed and compared the available methods,synthesized the arsenic compounds in our laboratories, and provided characterization information. On the basis of reaction yield, ease of synthesis and purification of product, safety considerations, and our experience, we recommend a method for the synthesis of each of these arsenic compounds.