Liquid chlorine

Specification: IS: 646-1986 (reaffirmed in 1996).

Description: The chemical is a clear yellow liquid and, when evaporated over a clean white tile, leaves no residue.

Composition: When tested to the method prescribed in appendix 'A' IS: 646-1986, the vapourised liquid contains not less than 99.8 per cent by volume of chlorine gas.

Properties and storage: Liquid chlorine is a clear amber-coloured mobile fluid and is about one-and-one-half times the weight of water. It evaporates extremely rapidly when spilled, one volume of liquid forming 460 volumes of gas. Thus, a liquid chlorine leak may be extremely hazardous, as the quantity of chlorine given out is many times greater than that from a gaseous leak.

Chlorine is slightly soluble in water; the maximum solubility being approximately 1 per cent at 10° C. Chlorine cylinders and containers should be stored in a dried ventilated place, protected from excessive heat and direct sunlight. It is preferable that the storage room be fire-proof. Storage near gangways or in sub-surface locations should be avoided.

Uses: Chlorine is used mainly as a bleaching agent and a disinfectant. It is also used in metallurgy and in the manufacture of organic and inorganic chlorinated products.

Safety precautions:
1. Even a minor leak must be attended to immediately. If the leak occurs in the containers in which the chlorine is being used, the container valve should be closed immediately.
2. Certified gas masks should be used whenever chlorine is present in significant quantities. The gas mask should be inspected frequently.
3. Follow routine first-aid procedures during a minor incident of gassing, but in an emergency call a physician immediately.
4. Water should not be spread on a chlorine leak.
5. Leak at valve steams can often be stopped by tightening the valve packing nuts and/or closing the valve.

Packing: 900-kg and 1,000-kg cylinders.

Liquid bromine

Specification: IS: 2142-1992 (reaffirmed in 1997).

Description: A dark reddish-brown fuming liquid with a highly irritating odour.

Properties and storage: Liquid bromine is a dark, reddish-brown, fuming, volatile liquid with a suffocating odour. Bromine attacks all metals and organic tissues. It vaporises at room temperature.

One litre of bromine weighs about 3.1 kg. One ml of bromine dissolves in about 30 ml of water. It is freely soluble in alcohol, chloroform, ether, carbon disulphide, carbon tetrachloride and concentrated hydrochloric acid. Liquid bromine should be stored in well-stoppered containers.

Normally, bromine is stored in amber-coloured glass containers or glass-lined steel tanks, but dry bromine can be stored in well-designed lead-lined or monel drums.

Uses: Bromine is used primarily in the manufacture of organic and inorganic bromides. It is an important reagent in the preparation of organic compounds involving a bromination step. It is also used in water treatment, shrink-proofing wool, as an intermediate for fumigants, as fire-extinguisher fluid and military poison gas.

Safety precautions: While handling bromine, always keep ammonia water within reach.

Packing: 3- and 3.5-kg glass bottles.

Hydrobromic acid

Specification: T C specification.

Description: A clear liquid, colourless to pale yellow when packed and may turn yellow to brown with time.

Properties and storage: Hydrobromic acid is a concentrated solution of hydrogen bromide gas in water. Solution with strengths higher than about 48 per cent fume freely when exposed to the atmosphere.

These fumes are extremely corrosive and an irritant to the mucous membrane. A solution of less than 48 per cent is usually easier to handle and store. Hydrobromic acid is sensitive to light, which slowly decomposes it and imparts to it a reddish-brown colour.

Uses: Concentrated hydrobromic acid is used principally in the preparation of certain organic chemicals and vitamin A.

Packing: 40- to 55-kg HDPE container.

Sodium bromide (photographic grade)

Specification: IS: 5380-1976 (reaffirmed in 1997).

Description: The material is in the form of small white crystals or crystalline powder, free from extraneous impurities. It absorbs moisture from the air but it is not deliquescent.

Appearance of solution: A freshly-prepared solution of 20g of the material in 100 ml of distilled water is clear, colourless and free from sediments.

Properties and storage: Sodium bromide absorbs moisture when exposed to the atmosphere. It should, therefore, be stored in a well-closed container in a cool, dry place.

Uses: The PQ grade is specially made for its use in photography.

Packing: 50-kg HM / HDPE drums with polythene liner.

Helping farmers reap bumper crops

Urea is an important nitrogenous fertiliser and Tata Chemicals is a major manufacturer of the product in India

Tata Chemicals makes urea at its fertiliser complex in Babrala. The complex has an installed capacity of 8,64,000 tonnes per year, which constitutes nearly 12 per cent of the total urea produced by India's private sector.

The Babrala facility, among the best of its kind in India and comparable to the best in the world, has set new standards in technology, energy conservation, productivity and safety. It is the only fertiliser plant in the country to use dual feedstock: natural gas or naphtha, or a combination of both.

The nature of the soil in many Indian regions is such that nitrogenous fertilisers are an important input for most crops. It is, thus, important that farmers have access to good urea at low cost.

Government aid

To make fertilisers available to farmers at affordable prices and to encourage balanced use, the Indian government regulates the sale price of fertilisers and provides a subsidy on urea and concessions on decontrolled phosphatic and potassic fertilisers. The government provides subsidy for the production and use of fertilisers under the retention price-cum-subsidy scheme (RPS), which was introduced in 1977.

The main objective of the scheme is to insulate farmers from fluctuations in fertiliser costs. It is also intended to ensure that fertiliser consumption does not suffer, as its growth was an essential ingredient of the Indian green revolution.

The RPS scheme is aimed at assuring a reasonable return on investment to indigenous manufacturers and to attract further investment in the fertiliser sector. The scheme has proved its worth in terms of stimulating higher production and use of fertilisers, thereby contributing to increased agricultural production in the country.

TCL's urea, a trusted farming companion

When farmers buy urea made by Tata Chemicals, they do so in the knowledge that they have in their hands a product that bears the Tata stamp of quality and reliability

By using Tata Chemicals' urea and taking advantage of the Tata Kisan Sansars (TKSs) run by the company, farmers can optimise the yield from their land.

Urea is an important nitrogenous fertiliser and Tata Chemicals is a major manufacturer of the product in India. The Babrala facility, among the best of its kind in India and comparable to the best in the world, has set new standards in technology, energy conservation, productivity and safety. It is the only fertiliser plant in the country to use dual feedstock: natural gas or naphtha, or a combination of both.

The nature of the soil in many Indian regions is such that nitrogenous fertilisers are an important input for most crops. It is, thus, important that farmers have access to good urea at low cost.

Millions of farmers in Uttar Pradesh, Haryana and Punjab, where the TKSs currently operate, utilise the basket of services offered by these farm centres, including advice on what crops to grow and which fertilisers to use.

TKSs stock seeds, pesticides and fertilisers for farmers to buy at affordable prices. They also lease out farm equipment and implements to farmers who cannot afford to buy expensive modern machinery.

The Information System on POP Termiticides and Alternatives

Termites are small, white to tan, sometimes black insects. They have an important role in recycling plant material and improving soils, but they also damage buildings and crops. To prevent or stop damage, chemicals including certain POPs (Persistent Organic Pollutants) have been used against termites (see POPtermiticides).

The Stockholm Convention aims at protecting health and the environment from POPs, starting with a list of twelve POPs. Five have been used against termites: aldrin, dieldrin, heptachlor, chlordane and mirex. Alternative termite management options are not always readily available, however, and Parties may request time-limited exemptions to use specific POPs against termites.

UNEP and FAO established the Global Termite Expert Group to assist countries in finding sustainable alternatives by providing guidance and information materials and technical support. This Information System on POP Termiticides and Alternatives aims to provide easy access to relevant information and guidance materials on termites and options for their management without POP termiticides.

About UNEP Chemicals Branch

UNEP Chemicals works to protect humans and the environment from adverse effects caused by chemicals throughout their lifecycle, and hazardous waste. It is the focal point of UNEP activities on chemicals issues and the main catalytic force in the UN system for concerted global action on the environmentally sound management of hazardous chemicals.

UNEP Chemicals’ program reflects global priorities identified by governments. It works directly with countries to build national capacity for the clean production, use and disposal of chemicals, and promotes and disseminates state-of-the-art information on chemical safety. In response to mandates from UNEP’s Governing Council, it facilitates global action, including the development of international policy frameworks, guidelines and programs, to reduce and/or eliminate risks from chemicals.

In delivering policy and technical assistance for the sound management of chemicals, UNEP Chemicals builds and strengthens partnerships with governments, organisations like the OECD, and non-governmental organisations. It also works closely with agencies within the UN family, including WHO, FAO, UNIDO, ILO, UNITAR, UNDP and the World Bank, and with the secretariats of the Basel, Rotterdam and Stockholm conventions on chemicals and wastes.

Illustrated Handbook of Physical-chemical Properties and Environmental

This volume, pesticides, completes the unique five-volume set of information-packed handbooks on environmental fate. The handbook contains fate calculations for a variety of pesticides of environmental interest today. No other volume offers current data in this convenient format.

The complete Illustrated Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals comprises an essential reference set. With detailed data on the properties and environmental fate of 500 chemicals of environmental interest, this unique set will be a standard reference for all environmental professionals.
-- Provides quick, convenient access to data on a wide variety of pesticides
-- Contains data sheets for 170 compounds to allow readers speedy access to precise data
-- Includes all known data sources

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Illustrated Handbook of Physical-chemical Properties and Environmental Fate for Organic Chemicals: Pesticide Chemicals
By Kuo Ching Ma, Wan Ying Shiu
Edition: illustrated
Published by CRC Press, 1997
ISBN 1566702550, 9781566702553
812 pages

Chemical property estimation

Our world is widely contaminated with damaging chemicals, and companies create thousands of new, potentially dangerous chemicals each year. Due to the difficulty and expense of obtaining accurate measurements and the unreliability of reported values, we know surprisingly little about the properties of these contaminants. Determining the properties of chemicals is critical to judging their impact on environmental quality and in making decisions about emission rates, clean-up, and other important public health issues. Chemical Property Estimation describes modern methods of estimating chemical properties, methods which cost much less than traditional laboratory techniques and are sufficiently accurate for most environmental applications. Estimation methods are used to screen chemicals for testing, design monitoring and analysis methods, design clean-up procedures, and verify experimental measurements. The book discusses key methods for estimating chemical properties and considers their relative strengths and weaknesses. Several chapters are devoted to the partitioning of chemicals between air, water, soil, and biota; and properties such as solubility, vapor pressure, and chemical transport. Each chapter begins with a review of relevant theory and background information explaining the applications and limitations of each method. Sample calculations and practical advice on how and when to use each method are included as well. Each method is evaluated for accuracy and reliability. Computer software, databases, and internet resources are evaluated, as well as other supplementary material, such as fundamental constants, units of measure, and more.

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Chemical property estimation: theory and application
By Edward J. Baum
Edition: illustrated
Published by CRC Press, 1997
ISBN 0873719387, 9780873719384
386 pages

Endocrine disrupting chemicals

Long-term environmental effects of chemical exposure have long been of concern and, more recently, chemicals which cause changes to the sexual development of exposed organisms have been identified. It is thought that low-level exposure to a wide range of chemicals may be affecting endocrine function, leading to a reduction in fertility and an increase in reproductive cancers. Endocrine Disrupting Chemicals reviews the scientific evidence and attempts to put the subject into context. Along with an overview of the issue, there is discussion of the specialised aspects in relation to wildlife; environmental oestrogens and male reproduction; and naturally occurring oestrogenic substances. With contributions from representatives of the Medical Research Council's Institute for Environment and Health and the US Environmental Protection Agency, the articles provide a comprehensive and detailed review of current issues. This book will be of interest to a wide readership, including industrial and environmental scientists, managers and policy makers.

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Endocrine disrupting chemicals
By Roy M. Harrison, R E Hester, Royal Society of Chemistry (Great Britain)
Edition: illustrated
Published by Royal Society of Chemistry, 1999
ISBN 0854042555, 9780854042555
151 pages

Chemistry of heterocyclic compounds: a series of monographs By Arnold

Key words and phrases

Phthalazine, cinnoline, synthon, reflux, Chem, substrate, hydrolysis, pyridine, dioxane, Heterocyclic Compounds, 2H)-phthalazinone, EtOH, Tetrahedron Lett, Melting Point, tautomeric, methylhydrazine, alkyl, aminolysis, pyridazine, tautomer





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Chemistry of heterocyclic compounds: a series of monographs
By Arnold Weissberger, Edward C. Taylor, Peter Wipf
Published by John Wiley and Sons
ISBN 047148587X, 9780471485872

Groundwater Chemicals Desk Reference By John Harold Montgomery

The third edition of the bestselling Groundwater Chemicals Desk Reference has been thoroughly updated and expanded. It provides information on environmental fate and transport in various media, organic priority pollutants, and chemicals commonly found in the workplace and the environment. New areas include bioconcentration factors, aquatic toxicity values, environmental degradation rates and corresponding half-lives, ionization potentials, aqueous solubility of miscellaneous compounds, three new data fields (sources of contamination, entropy of fusion, and Merck reference citations), 10 additional tables, and 2,600 references.


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Groundwater Chemicals Desk Reference: Desk Reference
By John Harold Montgomery
Edition: 3, illustrated
Published by CRC Press, 2000
ISBN 1566704987, 9781566704984
1345 pages

Acid-Base Interactions: Relevance to Adhesion Science and Technology, Volume 2

pt 1. Fundamental aspects of acid-base interactions -- pt. 2. Characterization of the acid-base properties of materials -- pt. 3. Applications of acid-base interactions.

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Acid-Base Interactions: Relevance to Adhesion Science and Technology, Volume 2




By K. L. Mittal
Edition: illustrated
Published by VSP, 2000
Original from the University of Michigan
Digitized 17 Dec 2007
ISBN 9067643254, 9789067643252
624 pages

Trends in organometallic chemistry research

Organometallic chemistry is based on the reactions and use of a class of compounds (R-M) that contain a covalent bond between carbon and metal. They are prepared either by direct reaction of the metal with an organic compound or by replacement of a metal from another organometallic substance. Research in organometallic chemistry is also conducted in the areas of cluster synthesis, main-group derivatives in unusual oxidation states, organometallic polymers, unstable organometallic compounds and intermediates in matrices, structure determination of organometallic compounds in the solid state [X-ray diffraction] and gaseous states [electron diffraction], and mechanisms of reactions of transient silylenes and related species. . In addition to the traditional metals and semimetals, elements such as selenium, lithium and magnesium are considered to form organometallic compounds, e.g. organomagnesium compounds MeMgI, iodo(methyl)magnesium and diethylmagnesium which are Grignard reagents an organo-lithium compound BuLi butyllithium; Organometallic compounds often find practical use as catalysts, the processing of petroleum products and the production of organic polymers.

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Trends in organometallic chemistry research
By Marin A. Cato
Edition: illustrated
Published by Nova Publishers, 2005
ISBN 1594544948, 9781594544941
214 pages

Purification of laboratory chemicals

Now in its fifth edition, the book has been updated to include more detailed descriptions of new or more commonly used techniques since the last edition as well as remove those that are no longer used, procedures which have been developed recently, ionization constants (pKa values) and also more detail about the trivial names of compounds. In addition to having two general chapters on purification procedures, this book provides details of the physical properties and purification procedures, taken from literature, of a very extensive number of organic, inorganic and biochemical compounds which are commercially available. This is the only complete source that covers the purification of laboratory chemicals that are commercially available in this manner and format. * Complete update of this valuable, well-known reference * Provides purification procedures of commercially available chemicals and biochemicals * Includes an extremely useful compilation of ionisation constants.

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Purification of laboratory chemicals
By W. L. F. Armarego, Christina Li Lin Chai
Edition: 5, revised
Published by Butterworth-Heinemann, 2003
ISBN 0750675713, 9780750675710
609 pages

SIRAL AND SIRALOX - SILICA DOPED ALUMINAS

Sasol markets a wide range of doped materials. Silica doped materials are sold worldwide under the trade names SIRAL and SIRALOX for their silica-alumina hydrates and oxides respectively.
The know-how gained from the production of high purity alumina products has been carried over to our range of doped materials so that the quality of the products is uncompromised and manufactured to the same high standards. The use of dopants affects the physical properties of alumina in many ways. SIRAL and SIRALOX is not only more thermal stable than the high purity aluminas but they are also more acidic materials.

PURALOX AND CATALOX - HIGH THERMAL STABLE AND LOW ATTRITION LOSS

PURALOX and CATALOX are the trademarks for the aluminium oxides (Al2O3 - gamma alumina, delta alumina and theta alumina) derived from the controlled activation of high purity aluminas.
The proprietary processes used in the preparation of these high purity aluminium oxides allow us to control many important physical properties and hence "tailor-made" a product for your process. Due to the tightly controlled processing conditions during and after manufacturing these aluminium oxides, PURALOX and CATALOX provide excellent specific catalytic activities, high surface area stability and low attrition loss.
PURALOX and CATALOX are arguably the best starting materials for the catalyst industry where consistency and an unobtrusive nature of the support are highly desired. These characteristics are of great importance for fluid and slurry bed reactions.
Due to their high thermal stability, PURALOX and CATALOX are widely used raw materials for wash coat formulations in emission control catalysts.

PURAL AND CATAPAL - HIGH PURITY BOEHMITE AND BAYERITE ALUMINAS

This family of aluminas (Boehmite, aluminum oxide monohydrate, AlOOH, and Bayerite, aluminum trihydrate Al(OH)3) has historically been used as supports or binders for catalysts in refinery and chemical processes. Due to the ability that these kinds of aluminas peptize in the presence of organic/inorganic acids they are widely used as shaped catalyst support materials.
Recent developments in many other applications have indicated these aluminas have applications in areas far beyond catalysis.

DISPERAL / DISPAL - COLLOIDAL BOEHMITE ALUMINA POWDERS

DISPERAL and DISPAL are the trade names for the high purity, highly dispersible, colloidal boehmite alumina powders manufactured by Sasol.
These aluminas, which are nano-sized in the dispersed phase, exhibit a unique combination of purity, consistency, and dispersibility that make them excellent materials for use in demanding colloidal applications. Traditionally our range of dispersible boehmites is used in applications such as sol-gel ceramics, binder for catalysis, refractory materials, rheology control, surface frictionising and paint detackification.
Other more recently developed uses include surface coating as well as polymer additives.

DISPERAL / DISPAL – dispersions of highly dispersible boehmite aluminas.

The main focus of Sasol's business unit 'Inorganic Specialty Chemicals', which belonged until 2001 to CONDEA Chemie, is on the production of synthetic aluminas derived from aluminium alkoxides. Our aluminas have high chemical purity and dispersibility. Important properties such as pore volume, particle size and specific surface area can be adjusted. Due to their variability of properties, these products over more than 30 years have found their way into a broad range of different applications, including catalyst supports, coatings, polymer additives, paint detackifier, sol-gel abrasives and ceramics, and many more.

We are a producer of:

1 High purity alumina
2 Dispersible alumina
3 Precipitated alumina
4 Hydrotalcite
5 Silica alumina
6 Alumina spheres, beads, and extrudates

Ichihara,Hexene and Aniline production

Ichihara changes

With the changing market for chemical feed stocks and products MCI announced in January 2009 that it was changing the face of production at its Ishihara works.
MCI will also reorganise its corporate structure by April 2009 to replace a current product portfolio which competes with Middle East products to an added-value product portfolio employing differentiated technology and which does not compete with Middle Eastern suppliers.
The first step will be the termination of the Ichihara EOG (ethylene oxide and ethylene glycol) plant due to large amounts of ethylene glycol being produced in Asia and the Middle East making the market uncompetitive (used to produce polyester fibre and antifreeze).

Market conditions for domestic ethylene glycol are expected to become extremely dull due to large supplies of EG coming from numerous plants newly established in the Middle East and Asia. The Ichihara EOG plant will be shut down in November 2009. The 80,000 tons of ethylene used at the Ichihara Works for EOG production will then be diverted to production of value-added products.
MCI intends to construct a new 1-hexene plant that will use 40,000tpa of the ethylene surplus producing 30,000tpa by ethylene trimerisation using a new 600-fold chromium catalyst. The plant, which will require an investment of 7.5bn yen, will begin construction in November 2009 and is expected to be completed by October 2010 with commercial operation starting in December 2010.

Hexene

1-hexene is used as co-monomer of HAO-LLDPE (high-alpha olefin-linear low-density polyethylene) and HDPE (high-density polyethylene). The global consumption of the chemical is around 650,000tpa with an expected growth rate of 6% to 7% per annum.

MCI in a joint venture with Idemitsu Kosan Company Ltd, as Prime Polymer Co Ltd, uses 1-Hexene to produce a metallocene linear low-density polyethylene called Evolue using gas-phase polymerisation (for this production 1-hexene has previously been purchased from external suppliers).

The output of Evolue will increase from 240,000tpa to 300,000tpa. Evolue has superior strength, transparency, and sealing properties than other linear low density polyethylenes produced with Ziegler-Natta catalysts. MCI will now produce specialist polyethylene and polypropylene for the markets using its unique patented technology.

Aniline production

In January 2009 MCI announced its decision to withdraw from aniline sales by September 2009 and terminate its 66,000tpa production plant at Ichihara by March 2009. The decision is due to the increased production of aniline by methane diisocyanate (MDI) related manufacturers resulting in a decline in market demand.
Mitsui Chemicals Polyurethanes Inc's Ohmuta Works at Fukuoka uses aniline produced at its own plant in MDI production. Only 1% of the phenol produced at the plant is needed for aniline production and the remainder of the phenol production is supported by increased demand for bisphenol.

The Ichihara Chemical Plant in Japan has been run by Mitsui Chemicals since 1967

The Ichihara Chemical Plant in Chiba, Japan has been run by Mitsui Chemicals Inc (MCI) since it first went into operation in 1967.
The main work of the petrochemical plant in the past has been based around its central ethylene production facility which supplied feedstock materials to produce polymer resins and derivatives for the world market (612,000tpa of ethylene).

The 1,390,000m² plant produces petrochemicals such as olefins, aromatic hydrocarbons, polyethylene, polypropylene, and TBA and basic chemicals such as phenol, BPA, acetone, epoxy resin, ethylene oxide, ethylene glycol, and aniline.

Bottles Holding Hot Liquids Leach Chemicals

Outdoor adventurers take note: Those hard plastic water bottles may leach hormone-mimicking chemicals if you fill them with piping hot water. (Mothers take note, too: Some baby bottles may be made of the same plastics, and could be subject to similar leaching.)

New research by University of Cincinnati scientists shows that Bisphenol A in polycarbonate plastic bottles used by rock climbers is more likely to leach out into the liquid when that liquid is hot. The temperature of the water is more important than the age of the bottle; some had speculated that deteriorating bottles would leach more of the chemical. The research is published in the journal Toxicology Letters.

Bisphenol A is among a class of chemicals, known as endocrine disruptors, that is causing growing concern among some scientists. Though legal to use and defended vigorously by manufacturers, these chemicals can mimic sex hormones at low levels, and that has raised fears they could cause subtle but lasting effects, particularly on developing fetuses and young children. The brain and reproductive system are most often affected in laboratory animal studies, but tests so far on humans have not been conclusive.

Lab on ice

Experimental apparatus made from ice can be used as detecting systems for solvent extraction and chromatography, claim Japanese scientists. The apparatus is cheaper, more readily available and more environmentally friendly than current equipment, they say.
Tetsuo Okada and colleagues at the Tokyo Institute of Technology used ice to make a liquid-core waveguide, a device for guiding light through liquid-filled channels. Guiding light through liquids is difficult because they have low refractive indices, meaning that they slow down the speed of light. But if the liquid is surrounded by cladding with a lower refractive index, the cladding reflects the light back into the liquid, keeping it on course through the channel without significant loss of intensity.
'Most current liquid-core waveguides are fabricated with Teflon AF-2400 [a fluoropolymer plastic] but it adsorbs various substances on its surface and is damaged even by weak mechanical contact. It also has a high cost,' explains Okada. 'Water-ice is much less expensive and, of course, is environmentally friendly.'

Chip mimics metabolism

Drug metabolism studies can be conducted on smaller samples than before thanks to an on-chip electrochemical cell designed by European scientists.
Electrochemical cells can mimic the oxidative metabolism of drugs within the body. By coupling them to mass spectrometers or liquid chromatographs, scientists can detect and identify the metabolites.
Mathieu Odijk, at the University of Twente, Enschede, the Netherlands, and colleagues made a glass chip containing the usual three electrodes found in an electrochemical cell - the working, reference and counter electrodes - plus an extra sensing electrode to detect generated species. They connected the chip to a liquid chromatography-mass spectrometry (LC-MS) system. When they injected a solution of amodiaquine, an antimalarial drug, through the chip, they showed that the cell oxidised the drug, forming all its major metabolites, which were detected by LC-MS.

Other electrochemical cells are commercially available but Odijk says his uses much smaller sample volumes. 'With this chip, new drugs can be studied faster and with more ease,' he says. He adds that the counter electrode is located in a separate side-channel from the other electrodes, which prevents unwanted side products appearing in the measured spectrograms.

'This chip is used in combination with tools like LC and electrospray-MS. A very logical but technically challenging next step is to combine these three tools onto a single lab-on-chip, while keeping the fabrication costs within acceptable limits,' says Odijk.

Magnetic beads clean up phage display

Microfluidic washing can improve drug candidate identification, according to US scientists.
Tom Soh at the University of California, Santa Barbara, and colleagues used micro-magnetic separation (MMS) to standardise the washing step in phage display, a method used to find proteins that interact strongly with disease-causing molecules, such as certain enzymes.
A bacteriophage (phage) is a virus that infects only bacteria. In phage display, scientists insert a new gene into a phage's genetic material. When bacteria process the new gene, they make a new protein, which is exposed on the phage's surface. Using a collection of around a billion phages each with a different inserted gene, scientists can create a library of phages, each displaying a different protein. They then expose the library to the immobilised target molecule. Some of the proteins bind to the target while the unbound phages are washed away. The bound proteins are potential drug candidates and are studied further.

The process requires a lot of the target molecule, explains Soh, which is problematic when it is in limited supply. It also yields false positives when proteins bind to the target's solid support rather than the target itself. 'It is also challenging to control accurately the stringency of washing in a reproducible way,' Soh adds - using a faster or longer wash flow can strip off bound phages from the target.
Soh's MMS device consists of a glass channel with nickel patterns on its surface. Soh coated magnetic beads with a target molecule then mixed the beads with a phage library in the channel. He left the mixture for 30 minutes, during which time some of the phages bound to the beads. When he applied a magnetic field to the channel, the beads stuck to the nickel and were held firmly in place while the unbound phages were washed away. He then removed the magnetic field, eluting the phage-carrying beads. Soh explains that he can alter the flow rate through the channel to maximise the quantity and diversity of the protein yield.
'MMS readily lends itself to incorporation into an automated system and provides a foundation for rapid and directed phage display,' Soh concludes.

Issue 4 of Chemical Technology now published

Issue 4 2009 of Chemical Technology is now available online. The complete issue can also be downloaded in pdf format.

Instant insight: Bone repair breakthrough
Thomas Webster and colleagues at Brown University, Providence, US, explain why today's bone implants are so much more than your grandparent's hip replacement thanks to nanotechnology.

Interview: Molecular logic
A Prasanna de Silva tells Nicola Wise about sensors, supramolecular chemistry and how Sri Lankan percussion can play a part in Irish music.

This issue's Application highlights include UV-sensitive indicators that change colour when there is a danger of sunburn.
Chemical Technology is free to view online and news items link directly to the original research articles, which are free to access for a limited period of time.


Downloadable Files
Chemical Technology issue 4 2009 PDF (1264k)
PDF files require Adobe Acrobat Reader

Lasers blow cells over microwalls

Scientists have used the unusual curving properties of laser beams to hurl microparticles and cells over walls.
Jörg Baumgartl at the University of St Andrews, UK, and colleagues used non-diffracting laser beams to transport particles between microwells. Baumgartl likens the laser beams to micrometre-sized snowblowers. The microparticles and cells are attracted to the bottom of the chip and then 'blown' upwards in an arc by the laser , he says.
Normal laser beams travel in a straight line and their light spreads out over distances. 'For instance, the beam emitted by a laser pointer would have the size of several hundred kilometres were it to reach the Moon,' explains Baumgartl. However, the non-diffracting laser beams he used travel in a curve without spreading out.

In most microfluidic studies, scientists move particles between chambers using a liquid flow. 'Our method opens an alternative route to transport, mix or sort microparticles and cells within the same microfluidic chip,' says Baumgartl.
'This is an important step forward in increasing the functionality of microfluidic environments by allowing particles to be transferred between different media,' says Ewan Wright, an expert in optical sciences and physics at the University of Arizona, Tucson, US. 'It is a wonderful example of how, over time, fundamental research, here on novel laser fields, can bring about highly innovative results in applied science.'
Baumgartl anticipates the method will lead to high-throughput, automated chips that will mix and sort microparticles and cells or mediate chemical reactions. It could be used to study cell processes and selectively expose cancer cells to drugs, he adds.

Magnets control drug release

A smart tissue-like biomaterial that can release drugs in response to a magnetic trigger has been created by UK scientists.
Simon Webb and colleagues from the University of Manchester used magnetic nanoparticles to glue together dye-containing vesicles then embedded them in a hydrogel. Webb positioned the vesicles within the hydrogel using magnetism and showed he could release the dye using an alternating magnetic field as a trigger. Webb says this indicates that the tissue-like gel could be used to store drugs and deliver them to the site of disease without affecting the surrounding tissue.
Although the group have previously used vesicles to mimic cells sticking together, Webb says the magnetic particles and hydrogel matrix strengthen the assemblies and make them easier to control. 'Gratifyingly, this combination has provided robust materials that can be patterned and release biochemicals in response to a magnetic trigger,' he says.
'The clever part of all this is the way in which the authors interface their magnetic triggers with vesicles using precisely controlled non-covalent interactions,' says David Smith, who investigates nanoscale gel-phase materials at the University of York, UK. 'Embedding the resulting triggered-release system within a hydrogel then generates the kind of material which could be used for drug delivery.' He adds that an alternating magnetic field is ideal for clinical use as it does not adversely affect healthy tissue.
Webb says they are working to create smaller patterns in the hydrogel matrix, and to magnetically trigger the release of cell messenger molecules such as growth factors, to enable use of this technology for biomedical applications.

A new twist on actuator architecture

Scientists have built a novel type of actuator - a device that converts energy into motion - with an artificial opal embedded within it.
To make the actuator, Kwang-Un Jeong at Chonbuk National Unversity, Jeonju, South Korea, and colleagues put colloidal silica in water, where it formed a strip of single crystalline opal one tenth of a millimetre thick. They embedded the strip in a layer of poly(dimethylsiloxane) polymer then added a layer of polyurethane (PU)/2-hydroxyethyl methacrylate polymer on top. Finally, they sealed the bi-layer strip inside a layer of glass.

The team placed the strip in different solvents and found that it responded differently depending on the solvent's hydrophobicity. The strip curled up to form a right handed spiral in hydrophilic solvents, such as acetic acid, and a left handed spiral in hydrophobic solvents, such as hexane. The curling effect is due to the difference in swelling ratios between the two polymer layers, explains Jeong. He showed that the right-handed spirals display different colours depending on the angle they are viewed from but the left-handed ones do not.
'Using a bilayer polymer photonic system to create colour-tunable spiral photonic actuators is a simple and elegant idea,' says Christopher Li, an expert in soft matter and hybrid materials at Drexel University, Philadelphia, US. 'Being able to control the macroscopic handedness of the spiral is fascinating. Slightly changing the sample architecture could lead to profound shapes, such as a helix.'
According to Jeong, the actuators even respond to gaseous solvents. He says that the device may have varied applications: 'These colour-tunable, reversible spiral photonic switches can be useful as mechanical actuators and electrical devices, as well as optical components. Our ultimate goal is to construct complicated 3D objects from programmed 2D structures.'

Process technology

Haldor Topsoe, is providing its process technology for the ammonia production plants. The contract was awarded in May 2008. Haldor Topsoe commented that it saw the contract award as an "important milestone for the coming increased requirement for fertilisers worldwide".
Based in Denmark, Haldor Topsoe is a specialist in the development and use of catalysts. The company says that its ammonia synthesis catalysts are installed in more than half of the world's ammonia converters.
Urea process technology is being supplied by Italy's Snamprogetti, while Germany's Uhde Fertiliser Technology is supplying its urea granulation process technology.