Chemistry World blog (RSC)

Syndicate content
Updated: 11 hours 6 min ago

Fried eggs, frying pans and fluoropolymers

16 September, 2014 - 15:57

Guest post by Jen Dougan

Of all the components of a cooked breakfast, a perfectly fried egg is arguably the most important. It’s for that reason, despite the myriad of other factors to consider – size/weight/colour/celebrity chef endorsement – that a frying pan’s non-stick credentials are key.

Polytetrafluoroethylene (PTFE), the ‘big daddy’ of non-stick, was discovered by accident in 1938. While attempting to make a new CFC refrigerant, American industrial research chemist Roy J. Plunkett noticed that a cylinder of tetrafluoroethylene had stopped flowing but its weight suggested something still inside. In his own words, ‘more out of curiosity… than anything else,’ Plunkett and his assistant cut open the cylinder to discover it was packed at the bottom and sides with a white, waxy solid. Analysis showed that the material was chemically inert, thermally and electrically resistant, and had very low surface friction.

What they had discovered was PTFE, a linear fluoropolymer prepared by the free-radical polymerisation of tetrafluorethylene. The carbon–fluorine bond is the strongest single bond in organic chemistry and the fluorine substituents shield the carbon skeleton from attack, making it chemically inert. Because of its useful material properties (and far from thoughts of fried eggs) PTFE was branded as Teflon and found uses in the Manhattan project, aerospace industries and even gecko research (it is the only known material to which a gecko’s feet cannot stick). But how did Teflon make its way from nuclear research into our kitchens?

By the 1950s Teflon was being used in fishing lines and a French woman asked her husband, an engineer, to coat her aluminium cooking pans with the material. PTFE-coated non-stick cookware was created, and launched as TefAl (from Teflon Aluminium). By the 1960s PTFE–coated cookware was being used in kitchens on both sides of the Atlantic.

However, on searching recently for a new frying pan I found many instances of implied safety issues with PTFE, mostly from ‘eco pan’ manufacturers and advocates. Two main themes recurred in accusations against PTFE cookware: concerns over perfluorooctanoic acid (PFOA), a surfactant used in its production, and ‘polymer fume fever’ – symptoms caused by inhaling polymer decomposition products.

PFOA is an environmentally persistent chemical and, in the mid-2000s, was classified by the US Environmental Protection Agency (EPA) as ‘likely to be carcinogenic to humans’. DuPont, a major user and producer of PFOA, settled with the EPA in 2005 over its failure to report possible health risks associated with PFOA. While PFOA is not present in PTFE cookware itself (it is destroyed during the manufacturing process), it was an environmental concern and after EPA stewardship, PFOA is no longer manufactured nor used by the major global fluoropolymer manufacturers, including DuPont.

Aside from PFOA concerns, PTFE coatings do begin to degrade at 260 °C. The decomposition of the polymer coating produces fumes, which, if inhaled, can cause ‘polymer fume fever’ – temporary symptoms much like the flu virus (see Shusterman DJ, Occup Med. 1993 8(3) 519). But just how likely is this to occur? It is possible to rapidly heat a pan to >260 °C, but if you follow the manufacturer’s instructions and don’t heat an empty pan,you would likely avoid any instances. The most common fats used in cooking have a smoke point well below 260 °C, which should act as a sufficient indicator of pan temperature and kitchen safety. Obviously, heating the pan without fat as a temperature gauge is riskier and should be avoided.

Still not keen on PTFE? There are alternatives. Used for cookware since the Han Dynasty in China (206 BC – AD 260) and still popular with cooks today, cast iron pans have unquestionably stood the test of time. Cast iron frying pans come bare or with an enamelled coating. Bare cast iron pans are porous and to achieve a non-stick finish worthy of a fried egg, oil is polymerised to form a hydrophobic layer across the pan surface. This process, known as ‘seasoning,’ can be repeated as required (depending on treatment of the pan), though is usually recommended yearly.

I’m satisfied that with normal use, PTFE pans will produce perfectly fried eggs without adverse health effects (apart from a risk of increased cholesterol). The only remaining question is whether to have them over-easy or sunny side up?

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Meet our guest bloggers – Jen Dougan

16 September, 2014 - 13:53

My name is Jen Dougan and I am a Field Applications Scientist with an SME, developing diagnostic tools for clinical analysis. My job involves working with our R&D teams and customers in the field to drive and support product and applications development.

I recently moved into this position after a PhD and two post-docs (and a brief stint in science policy) in bio-nano-analytical chemistry. What I’ve loved about the transition into this role is the chance to ask questions and provide answers in a fast-paced, rigorous environment. It’s been fantastic to see some of the techniques used through my PhD and post-docs in action in a clinical setting.

Real world applications of chemical research are a central theme of this blog. I’ll be contributing regular posts here, to explore the chemistry in our every day lives. From the clothes we wear to the goods we use, it really is a chemical world.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Academic family: Sir Harold Kroto

11 September, 2014 - 17:35

Guest post by JessTheChemist

Scientists have a responsibility, or at least I feel I have a responsibility, to ensure that what I do is for the benefit of the human race’ – Harry Kroto

Thank you for your nominations for this month’s blog post. It was great to see so many of you getting involved in this series, highlighting interesting Nobel laureates for me to cover. However, I could only pick one winner, so I decided to write about Harry Kroto, inspired by this tweet from Bolton School:

@ChemistryWorld @JessTheChemist How about Bolton School Old Boy 'Sir Harry Kroto'?

— BoltonSchoolChem (@Chem_BoltonSch) August 20, 2014

Harry Kroto has a formidable CV. Not only is he a highly distinguished and talented chemist, but he does a great deal to improve the teaching of chemistry to future generations. This has included setting up the not-for-profit Vega Science Trust, which helps scientists communicate with the public at large, and even returning to his childhood school to build Buckyballs with students.

Kroto began his career at the University of Sheffield where he gained his PhD in high resolution electronic spectra of radicals. After time spent in Canada and the USA, he returned to the UK – to the University of Sussex – to begin his independent research career. His research concentrated on the identification of carbon chains in the interstellar medium, which included work at Rice University, where Kroto and colleagues, Richard Smalley and Robert Curl, discovered the existence of C60 or Buckminsterfullerene. The discovery itself has become a well known scientific story, recently retold by Rowena Fletcher-Wood here on the Chemistry World blog. After numerous publications on the subject, Curl, Kroto and Smalley were awarded the Nobel Prize in chemistry in 1996 ‘for their discovery of fullerenes’. As with many other Nobel laureates, there’s a detailed biography of Kroto published by the Nobel foundation here.

Kroto is related to a number of influential scientists. He is distantly related to Roger Kornberg, who won the Nobel prize in chemistry in 2006 for his work on the molecular basis of eukaryotic transcription. Kornberg was lucky enough to work for the Nobel prize winner, Francis Crick, who famously contributed to the proposal that DNA had a double helical structure, along with James Watson.

Kroto’s academic partners and fellow Nobel prize winners, Curl and Smalley also have impressive scientific pedigree. Curl’s academic father was E. Bright Wilson, a pioneer in spectroscopy, and grandfather was Linus Pauling, who won both the Nobel prize in chemistry and the Nobel peace prize. Curl is also academic brother to Dudley Herschbach, winner of the Nobel prize in chemistry in 1986 for contributions towards the molecular dynamics of elementary chemical processes. Hershbach shared the prize with the Hungarian-Canadian chemist John Polanyi and Yuan T. Lee, the first person from Taiwan to be awarded a Nobel prize. Smalley is academically descended from William Lipscomb, who took the 1976 Nobel prize in chemistry for his contributions to borane chemistry. Not shown in our family tree are Thomas Steitz and Ada Yonath, who both went on to win Nobel prizes after time spent in Lipscomb’s lab. Lipscomb also demonstrated his sense of humour by regularly presenting at the Ig Nobel awards. Curl is also connected to Peter Atkins, author of undergraduate students’ favourite physical chemistry textbook!

Sir Harry Kroto's academic family tree

As you can see, Kroto has an eclectic lineage, and rich academic family history, from chemical biologists to physical chemists. Do you want to know what your academic genealogy is? If so, head to academictree.org, where you can add yourself to the website and start creating your very own tree.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Funding for fiction’s favourite poison

9 September, 2014 - 13:46

‘As for monkshood and wolfsbane, they are the same plant, which also goes by the name of aconite.’ – Severus Snape, Harry Potter and the Philosophers Stone by J. K. Rowling

In Harry Potter’s very first potions lesson he learnt about the magical properties of aconite. Muggle chemists, it seems, are only one step behind the magical world.

©istock

Aconitine – spelt slightly differently by scientists – has a highly complex structure that has never before been synthesised in the lab. But now, Duncan Gill from the University of Huddersfield, UK, has been awarded a £133,481 grant to develop a synthetic route to obtain this illusive molecule.

Attempts to make aconitine began after Czech chemist Karel Wiesner revealed its chemical structure in 1959. Weisner went on to publish several papers on the synthesis of alkaloids and terpenoids, an important initial step towards making the molecule. However, it wasn’t until last year that a major milestone was reached, when a team of researchers from the Memorial Sloan Kettering Cancer Institute, New York, announced the total synthesis of the related compound, neofinaconitine. Building on the work of his predecessors, Gill will have to develop new chemical methods to reach his target molecule.

If successful, Gill, who has previously worked as a process chemist at AstraZeneca, will need to be particularly careful when handling this compound. Aconitine is a potent neurotoxin and has been dubbed the ‘Queen of poisons’. One of the most notable references to aconitine comes from William Shakespeare’s Romeo and Juliet: it is the main ingredient in the toxic potion drunk by Romeo with fatal consequences.

The grant has been provided by the Leverhulme Trust and will be enough to employ a full-time post-doctoral advisor. Only time will tell if they can bring this fictional favourite to life in a laboratory setting.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

The ‘ooh, that’s interesting’ moment

4 September, 2014 - 16:29

Guest post by Heather Cassell

©Shutterstock

Sometimes it happens when I’m reading a research paper, sometimes when I’m doing an experiment, analysing data or learning a new technique; or more often when I’m reading Twitter. It’s that moment when you discover something new and interesting, or re-discover a fact that you used to know, and it makes you pause and think ‘ooh, that’s interesting’. For me the discovery usually leads to a massive detour into reading things other than those I was meant to be reading or working on, but I always learn something from it and sometimes it’s actually relevant to my work. Whether it directly affects research or not, the ‘ooh, that’s interesting’ moment is at the heart of scientific investigation.

It can be great when it happens during an experiment, but it can also be deeply frustrating. An unexpected result forces you to seriously consider what is happening and to plan more experiments to further examine the anomaly. This encourages you to combine techniques, make use of all of the resources at your disposal or even seek out new collaborators. If the anomalous result is reliably proved correct and reproducible, then you will need to do more research to explain it. At its best, this is a very exciting time as you will get to learn new skills, create new knowledge and develop partnerships. At its worst, it can shatter your previous assumptions or even show that your idea or product is not as good as you think.

Personally, I really enjoy the flurry of activity associated with learning something new, especially a new experimental technique. I was recently involved with some experiments using atomic force microscopy (AFM) – I had a vague idea of what it was but I had never used this technique before. The analysis produced some amazing pictures but I had no idea what they meant, so I spent an enjoyable afternoon learning all about how AFM works and comparing the results we produced with results already published. The next time we used the machine I could analyse the images as they were formed, which was really helpful for determining if it was showing what we wanted or not. The ‘ooh, that’s interesting’ moment had provided the push I needed to learn a new skill.

Outside the lab, I really love spending time on Twitter. With so many scientists (and non-scientists) from different fields providing links to articles and blogs, there’s always more than enough to read. Just 10 minutes reading tweets can leave me with countless browser tabs open and new favourites to read. It’s now easier than ever to share your ‘ooh, that’s interesting’ moments with the world, meaning a tweet from a researcher half way across the globe can inspire new ways to think about my own research.

It is this process of discovery and continuous learning that is one of the main things I love about science. Now, back to Twitter…

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Oranges and Lemons

28 August, 2014 - 16:33

Guest post by Rowena Fletcher-Wood

Scurvy plagued early sailors, and although many treatments were tried and promoted, a simple cure was masked for centuries behind a series of mistakes and misunderstandings.

This story begins at sea, long into a voyage after the fresh food stock had long run out and the sailors were left with only grains, hardtack and cured meats to eat. The sailors would become desperate as scurvy began to set in. Sailors were lost to scurvy in vast numbers, with estimates as high as two million lives lost between 1500–1800 AD.

©Shutterstock

Scurvy is an unpleasant disease in every way. Although symptoms take weeks or months to develop, they get very nasty. First you become lethargic, anaemic and pale, and all of your joints and muscles ache. You lose your appetite and begin to develop spots on your thighs and legs. Soon you become feverish, sick, and weak; gums soften and bleed, legs swell, old wounds reopen. Depression sets in. Eventually, scurvy takes hold completely: your teeth fall out and gums turn blue, you bleed beneath your skin and from the follicles of hairs. You suffer cardiac arrest and die.

Scurvy is caused by a deficiency in vitamin C (ascorbic acid), which is present in many foods – including tomatoes, sweet peppers, strawberries and spinach – but in particular citrus fruits. Several pathways in the body rely on vitamin C; it is vital for building collagen in tissues. We also use it for lipid metabolism, neurotransmission and strengthening bone and blood vessels. Although many species are capable of synthesising their own vitamin C, humans and a few other animals cannot – it is an essential nutrient that must come from our diet. But until 1927, we didn’t even know it existed.

The ancient Greek physician Hippocrates knew that fresh fruit, especially citrus, had an antiscorbutic effect – it could prevented and cure scurvy. In 1747, James Lind systematically proved that the addition of citrus fruit to the diet both treated and prevented the disease, in a candidate for the first ever clinical trial. But the medical establishment were not convinced, and continued to promote other approaches, including good hygiene, exercise, avoiding tinned meat and improving morale. Some of these approaches were successful, including prescribing the peppery herb scurvy-grass, which is related to horseradish. Unknown at the time, scurvy-grass leaves are rich in vitamin C.

A common belief was that the acidic principle treated scurvy: doctors believed any acid would do and that citric acid in fresh fruits was merely the best. Accidental destruction of ascorbic acid in treatments that would otherwise have been effective was common. Although vitamin C is present in milk, this was destroyed by the new process of pasteurisation, leaving bottle-fed babies susceptible to scurvy. James Lind himself was guilty too, bottling and selling lime juice that promptly oxidised and became useless.

When the 1867 Merchant Shipping Act insisted that all ships carry citrus fruits, fresh lemons were substituted for cheap, abundant West Indian limes which were more acidic but had only a quarter of lemons’ ascorbic acid content. These fruits were juiced, stored in air and piped through copper tubing, oxidising the vitamin C. Later tests in 1918 showed the juice to be almost useless, but at the time this was masked by simultaneous advances in diet and marine travel that reduced the prevalence of scurvy.

We owe the discovery of vitamin C to guinea pigs. Two Norwegian physicians, Axel Holst and Theodor Frølich, decided in 1907 to induce in guinea pigs a disease called beriberi, now known to be cause by a deficiency of vitamin B1. They used the same dietary restrictions they had used to induce the disease in pigeons, but the guinea pigs developed scurvy instead. Pigeons produce their own vitamin C, but like us, guinea pigs cannot. This was an exciting moment in medical history: the diseased guinea pigs were the first examples of non-human scurvy sufferers.

In 1932, the Hungarian biochemist Albert Szent-Györgyi posted a sample of hexuronic acid – which he had isolated in 1927 – to the University of Pittsburgh, asking them to test it on guinea pigs with scurvy. The results would gain him the Nobel prize for medicine five years later, and hexuronic acid was renamed ascorbic acid to celebrate its antiscorbutic effect.

Decades of nutritional experiments and almost–correct hypotheses had seen scurvy become increasingly rare, but it took almost 200 years – from Lind’s nutritional trials to Szent-Györgyi’s experiments – to identify the secret in citrus fruits.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

A professional makeover for the old reaction scheme

21 August, 2014 - 17:50

Guest post from Tom Branson

A bright new reaction scheme has found its way to the cover of Inorganic Chemistry. Not content with old standard representations, this journal has been given the professional touch.

Framing metal complexes

The image puts a well needed shine on the conventional reaction scheme and perhaps suggests that we should now be teaching undergrads to paint as well as honing their ChemDraw skills. Two states of a porphyrin derivative complexed with zinc are shown here framed in audacious, golden swirls. And why not? If you’re proud of your work then go ahead and put a huge golden frame around it.

Let’s take a look at that zinc phthalocyanine complex, expertly drawn binding to HS. Then give it a proton, follow the two giant arrows and you reach liberated hydrogen sulfide and the original zinc phthalocyanine. In case you hadn’t got it yet, the artwork explains for us that this process is all about protonation. The background is also a nice touch. A fantastic network of neurons is on show, blasting off new thoughts of possible bioinorganic applications. Hydrogen sulfide is known to play a role in neurotransmission and its reactivity with metal complexes may find practical applications in that field.

This journal cover art was created by artist Shanna Zentner. She was recommended to the authors of the article by colleagues at the University of Oregon, after she had previously produced artwork for other faculty members.

Zentner’s foray into the scientific literature started when her husband needed a cover for a chemistry journal. They thought a painting of the research would do nicely and so Zentner’s chemistry art career took off. Since then her painting skills have been commissioned for a number of other journal covers, with the artist and scientists often meeting to discuss the work and how to develop the imagery. Zentner champions science communication and believes that this type of work is ‘invaluable to the advancement of scientific literacy in the general public.’

Hydrogen sulfide reactivity

The actual research probes more deeply into the mechanism of H2S binding to both zinc and cobalt phthalocyanine complexes. The team, led by Michael Pluth, show that whilst the zinc variety reversibly binds HS, the cobalt complex is instead reduced by HS and can be oxidised back when exposed to air. This redox activity results in a colour change that could be used in colorimetric HS detection.

Head over to Inorganic Chemistry for the full article and more bright results with metal phthalocyanine complexes.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Academic family: Sir William Ramsay

14 August, 2014 - 16:46

Guest post by JessTheChemist

‘The noblest exercise of the mind within doors, and most befitting a person of quality, is study’ – Ramsay

A few years ago I had the pleasure of meeting Jack Dunitz at the Swiss Federal Institute of Technology (ETH) in Zurich. Little did I know that he was the academic great-great-grandson of the UK’s first chemistry Nobel Laureate, Sir William Ramsay. After discovering this connection, I decided to delve deeper to see which other chemistry legends Ramsay is connected to.

Ramsay began his career as an organic chemist, but his prominent discoveries were in the field of inorganic chemistry. At the meeting of the British Association in August 1894, Ramsay and Lord Rayleigh both announced the discovery of argon, after independent research. Ramsay then discovered helium in 1895 and systematically researched the missing links in this new group of elements to find neon, krypton, and xenon1. These findings led to Ramsay winning his Nobel prize in 1904 in ‘recognition of his services in the discovery of the inert gaseous elements in air, and his determination of their place in the periodic system’.

Ramsay worked with a wide range of chemists before winning his Nobel prize. At the start of his career Ramsay worked with Rudolf Fittig in Tübingen, Germany. Fittig, a successful organic chemist, is particularly known for discovering the pinacol coupling reaction. Ramsay’s noteworthy academic brothers via Fittig are Ira Remsen and Theodor Zincke. Remsen is recognised for contributing to the discovery of the first artificial sweetener: his co-worker, Constantin Fahlberg, accidentally discovered Saccharin by failing lab etiquette 101 – not washing his hands after a day working in the laboratory.2 On the other hand, Zincke is most famous for supervising the father of nuclear chemistry, Otto Hahn, who claimed the Nobel prize in chemistry (1944) ‘for his discovery of the fission of heavy nuclei’.3 This makes Ramsay the academic uncle of Hahn.

As well as academic brothers and nephews, Ramsay’s direct academic descendants have also achieved greatness. Frederick Soddy, Ramsay’s academic son, carried out research into radioactivity and proved the existence of isotopes, for which he won the 1921 Nobel Prize in chemistry.4 Unfortunately for the chemistry community, Soddy’s interests diverted to economics and politics, so he has no prominent academic offspring to speak of. Interestingly, he also has a lunar crater named after him! Other chemistry Nobel prize-winning descendants of Ramsay include the two-time winner, Frederick Sanger (1958, 1980), and Barry Sharpless (2001), who are both his academic great-great-grandsons. Ramsay also has more diverse Nobel prize winners in his family tree, with two winners for physiology or medicine: Har Gobind Khorana (1968) and Konrad Bloch (1964).

This summary of Ramsay’s academic family is by no means the complete list, but this does demonstrate that one great chemist can have an enormous effect on the generations of chemists to come. As you can see, Nobel prize winners seem to have excellent academic dynasties, but perhaps it isn’t the fact that their mentor won a Nobel prize that inspired them to greatness but their work ethic and abstract way of thinking.

In future posts we will look at other Nobel prize winners and the effect that they may have had on their academic offspring. If there is a particular winner that you would like to see featured, you can contact me on Twitter (@Jessthechemist).

 

References

1: Sir William Ramsay – BiographicalNobelprize.org. Nobel Media AB 2013. Web. 6 Jan 2014.

2: Chemical Heritage Magazine ‘the persuit of sweet:a history of saccharin’

3: Otto Hahn – Biographical. Nobelprize.org. Nobel Media AB 2013. Web. 6 Jan 2014.

4: Frederick Soddy – Biographical. Nobelprize.org. Nobel Media AB 2013. Web. 7 Jan 2014.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Meet our guest bloggers – Jessica Breen

14 August, 2014 - 16:24

I am a postdoctoral fellow at the Institute of Process Research and Development (iPRD) at the University of Leeds. My research is on the synthesis of chiral amines relevant to the pharmaceutical industry but I have a general interest in organic chemistry, catalysis and sustainable methodologies. When I am not in the lab, I blog at The Organic Solution on a range of topics including chemical research, postdoc life and outreach experiences. Recently, I have become interested in the connection between chemists across the globe which has led me to create an academic twitter tree.

To continue this academic tree theme, this blog will explore certain strands of the chemistry Nobel Laureate family tree using the Royal Society of Chemistry’s Chemical Connections. The blog will delve into the life and heritage of different chemistry Nobel Laureates and, amongst other things, we shall find out if having a Nobel winner in your lineage could have an effect on your career, for example, does having a Nobel winner in your ancestry mean you are more likely to achieve academic greatness? If there is a Nobel winner that you would like to see featured, please get in touch.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Tales of the abandoned glassware

7 August, 2014 - 12:21

Guest post by Heather Cassell

Mysteriously abandoned?
©iStock

I love working in the lab. I’m happiest when I’m pottering about among the bottles and the beakers getting on with my work. Most of my experience has been in multi-group labs of varying sizes; all have generally been good fun to work in, with lots of people to talk to who each have different skills and experiences. This can be very useful when you need any help, especially when you are learning new techniques.

One thing you can rely on happening in the lab at some point, especially a large lab used by many groups, is the appearance of Mysteriously Abandoned Glassware. Usually the bottle, beaker, or flask is unlabelled. If you’re lucky enough to have a label, it’s guaranteed to be so faded you can’t read it. Sometimes the glassware contains a colourless liquid; other times a crystalline material, evidence of the previous presence of now long lost liquid. A common variation of the Mysteriously Abandoned Glassware is the flask/beaker of something that has had Virkon (a pink disinfectant) added to it and left in the sink, again with no label in sight to point us to the perpetrator. Over time, the pink Virkon discolours, but the glassware remains Mysteriously Abandoned.

Over the years, I have realised I have a fairly low mess tolerance (compared to the other people I work with), at least in the lab; my office desk is another matter! I like a clean and tidy bench to work on and the same goes for communal areas, so while others are happy to ignore the things that have been left, I find myself doing something about it. I’m always the one tidying up as I am waiting for the centrifuge to run, or doing other lab jobs (filling up hand towels, checking stock levels, emptying disposal bins…). In the case of Mysteriously Abandoned Glassware, I end up trying to find the owner (often a mystery) then trying to work out what it is.

More often than not, the solution is something fairly innocuous like a buffer (Tris or PBS), which we dilute from concentrated stocks, or an alcohol (ethanol or methanol). After I’ve worked out what it is and how to dispose of it, I’ll send the glassware to be washed or do it myself. Within hours, you can guarantee that someone will come and say, ‘have you seen my [insert common solvent here]? I left it somewhere…’ The lab will stay reasonably tidy for a few days or maybe even a few blissful weeks, before another piece of Mysteriously Abandoned Glassware materialises and the cycle continues.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Meet our guest bloggers – Heather Cassell

7 August, 2014 - 12:09

I’m Heather Cassell (née Stubley). I did a BSc in biochemistry and genetics at the University of Leeds, then I moved to the University of York where I did an MRes in biomolecular sciences followed by a PhD investigating enzyme activity in non-aqueous solvents. I am currently finishing my first postdoc position working as a research fellow in molecular and cell biology at the University of Surrey. The project involves cloning proteins of interest and attaching them to polymers or other nanoparticles then assessing their toxicity and cellular location in liver related cell lines.

I decided to write a ‘life in the lab’ blog strand because I love working as a scientist, especially the time spent in the lab itself – despite the many challenges. It gives me a chance to share my enthusiasm for working as a researcher and all things science-related. I plan to give an early career scientist’s view of life in the lab, balancing work and childcare, procrastination and productivity, research and recreation.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

The discovery of Buckyballs

31 July, 2014 - 16:31

Guest post by Rowena Fletcher-Wood

Among the many accidental discoveries through the ages is an experiment designed to probe carbon molecules in space, which unearthed a new terrestrial molecule.

Harry Kroto with buckyballs
© Science Photo Library

It all happened in an 11-day whirl, between 1 September 1985, when Harry Kroto first arrived at Rice University, US, and 12 September, when he, along with Richard Smalley and Robert Curl, submitted a paper to Nature: C60 Buckminsterfullerene’. Eleven years later, in 1996, the three were awarded the Nobel prize for chemistry.


Indeed, a Nobel prize may have been some consolation to Smalley and Curl, who were initially reluctant to delay their research on silicon and germanium semiconductors to let Kroto play with carbon. Kroto was exploring a completely different area of research: cyanopolyynes, alternating C–N chains detected in interstellar space using radiotelescopes. Although the evidence for their existence was good, the origin of these compounds was still unknown. Kroto postulated that they may form in the vicinity of red giants, and wanted to use Smalley’s laser-generated supersonic cluster beam to recreate this high-heat atmosphere and uncover mechanisms for their formation.

After agreeing to let Kroto use the apparatus, the three scientists, helped by graduate students James Heath, Sean O’Brien and Yuan Liu, loaded a graphite disk onto the beamline in a helium chamber and vaporised it into a plasma at temperatures exceeding the surface temperatures of most stars. Under high pressure helium, the vapour cooled and condensed, forming new interatomic bonds and aligning into different-sized clusters, which were immediately pulse ionised and swept into a mass spectrometer for analysis.

First, the students found Kroto’s expected carbon snakes, but then they noticed a distinct peak at C = 60 and a smaller one at C = 70. The abundance of C60, and increasing yield under higher pressure conditions suggested a very stable, closed-shell macromolecule. Unlike Kekulé’s benzene ring, buckminsterfullerene was not identified through dreaming, but through the resourceful application of sticky tape and cardboard cut outs. The model was proposed: a truncated icosahedron, consisting of twenty hexagons and twelve pentagons, like a carbon football. The name, buckminsterfullerene, was inspired by the architect famous for his similar-looking geodesic domes.

Since then, enthusiastic exploration into other fullerene allotropes has revealed that we could have accidentally discovered buckyballs long ago using much lower-tech equipment: a burning candle produces buckyballs in its soot by vaporising wax molecules. Not only that, but buckyballs occur in geological formations on Earth and, since 2010, have been detected in cosmic dust clouds. The ball-like carbon molecule wasn’t even a new idea: between 1970 and 1973, three independent research groups led by Eiji Osawa of Toyohashi University of Technology, R W Henson of the Atomic Energy Research Establishment, and D A Bochvar of the USSR, predicted the existence of the C60 molecule and calculated its stability. However, their work was purely theoretical, and didn’t get the attention it deserved. Buckyballs were discovered, rather than made, so perhaps it’s not surprising that they were found by accident: more surprising is that that weren’t found before.

 

References:

The Chemical Heritage Foundation – Richard E. Smalley, Robert F. Curl, Jr., and Harold W. Kroto

Press release – The Nobel Prize in Chemistry 1996: Robert F. Curl Jr., Sir Harold Kroto, Richard E. Smalley

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Meet our guest bloggers – Rowena Fletcher-Wood

31 July, 2014 - 16:11

I am a keen science communicator, a doctoral researcher in materials chemistry at the University of Birmingham and a climbing instructor.

Most of all, I like telling stories.

When I climb, I learn to fall. When I do chemistry, I learn to look for the unexpected. I have to agree with Einstein: researchers don’t know what they’re doing, that’s what makes it research – we’re fumbling around in the dark waiting for accidents to happen, and hopefully yield good results. Some of the things we see and use every day were discovered purely by accident – some of the things I will be writing about here.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Journal cover art that will brighten your day

24 July, 2014 - 16:22

Guest post from Tom Branson

After browsing the recent chemical literature, I have finally found enlightenment. I have quite simply been left in a trance after witnessing a recent cover from Chemical Society Reviews.

A colour explosion

There’s so much colour in this image I just don’t know where to begin. So let’s start by taking a look at that green globe. Surely a prophecy of a future world when green chemistry has finally paid off and this development also seems to have led to a plethora of plant life sprouting from the Earth. Holding that planet aloft are two pairs of caring hands. An adult gently holds a child’s tiny hands and together they embrace this new future. Peace and love and chemistry, what more could you ask for?

And what about that background? Wow, they didn’t hold back with the colour palette. With some journals still charging for colour figures I bet these guys always get their money’s worth.

So there are adult hands, clasping a child’s hands, supporting the world, sprouting a bouquet of flowers, in front of a mega-rainbow, oh it’s almost enough to make me quit science and run off to join a cult.

Seriously though, the cover is a wonderful attempt to highlight sustainability and forward thinking, something that is sadly all too often lacking in modern society. The author of the paper, Jinlong Gong of Tianjin University, China, tells me of his hope that ‘this cover can call up the attention of people to consider more about the future of our world’. Nicely said.

There are not really many clues in the image as to what the published science is about but the keen eyed among you may have spotted a few water droplets on the plant leaves. Was the printer simply too close to the water cooler at Chem. Soc. Rev. headquarters, or is this paper all about solar water splitting? Aha, the latter of course.

Photocatalysis

The cover art is for a review article about a really promising solution for solar energy; tantalum-based semiconductors. Visible light can be absorbed by these semiconductors and used in solar water splitting, converting solar energy into chemical energy. The team from China highlight that while this type of photocatalyst is still far away from use in practical applications, improvements in the efficiency and stability of these systems give hope to the tantalum-based community.

Those wanting to know more about this tantal(um)ising hope for the future can access the article over at Chem. Soc. Rev.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Meet our guest bloggers – Tom Branson

24 July, 2014 - 16:00

I recently completed my PhD at The University of Leeds where I was investigating protein-carbohydrate interactions and protein assembly. I’m a synthetic biologist now working on biomolecular interactions, based in The Netherlands. I also blog about science communication issues and chemistry trivia over at Chemically Cultured.

Here at Chemistry World, I will be writing a regular blog series to highlight some of the best academic journal covers – the images that grace the front of those magazines we all paw through. Many of you might think that academic journals are a place where only serious facts and tables of data find their home, but, at the very start of many journals lies an artistic outburst.

These journal covers are a great place for researchers to highlight their work and at the same time, show off their artistic skills. Many covers have caught my eye over the years and they deserve to be promoted for the talent and, more than often, eccentricities that show in these designs. Imagination, creativity and communication are core principles in the world of science and all this comes to the fore on the front cover of our favourite periodicals.

 

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

YMS winners

10 July, 2014 - 14:50

The Royal Society of Chemistry’s 3rd Younger Members Symposium (YMS2014) was held towards the end of June at the University of Birmingham. Kicking off the day was Lesley Yellowlees who gave an inspirational plenary lecture covering her research and career path, in one of her final acts as RSC president. ‘Aspire to be the president of the Royal Society of Chemistry – it’s the best job ever,’ she told the audience. She also shared lessons she had learned over the years including: develop your own style, grasp opportunities and find ways of dealing with difficult colleagues.

Jamie Gallagher, the University of Glasgow’s public engagement officer, energised everyone after lunch by talking about his work and why public engagement makes you a better academic. Public engagement doesn’t necessarily have to involve standing on a stage like Jamie does on a regular basis. He gave some fantastic advice on the many schemes and organisations to get involved with such as Cafe Scientifique and your local RSC section.

Both excellent talks but the real meat of the day was comprised of poster sessions and seminars where attendees shared and quizzed each other on their research. Chemistry World was delighted to sponsor its first ever poster prizes in the inorganic and materials category. And the winners were…

First prize went to Giulia Bignami from the University of St Andrews.

Giulia Bignami: ‘The research work described in my poster focuses on the synthesis, according to the assembly-disassembly-organisation-reassembly (ADOR) method, of 17O-enriched UTL-derived zeolitic frameworks and their subsequent characterisation through 17O and 29Si solid-state NMR, involving both 1D and 2D spectral techniques, in magnetic fields ranging from 9.4T to 20.0T. We showed how 17O and 29Si NMR-based structural investigation proves extremely helpful to gain insights into the synthetic process employed, thus shedding light on the way new and targeted zeolitic structures could be achieved.’

Second prize went to Gurpreet Singh from the University of Central Lancashire.

Gurpreet Singh: ‘The aim of the research is to find new ion exchange materials for use in the nuclear industry. The problem with some of the current ion-exchange materials is that they are not stable to the conditions found in the waste pools at nuclear sites. Zirconium phosphates have been proposed to be more stable and by doping other metals into the structure in place of zirconium it might be possible to create new materials which have increase selectivity for the cations of interest (strontium and caesium). The work presented shows that yttrium can be successfully introduced into the structure of alpha-zirconium phosphate and the ion-exchange experiments are on-going.’

Third prize went to Daniel Lester for a poster about work he did at the University of Sussex.

Daniel Lester: ‘In the field of VOC (volatile organic compound) degradation by photocatalysis, P25 (powdered TiO2 of 75% anatase 25% rutile composition) is often seen as a benchmark material. However, in the continuous flow reactors used in industry, a powdered catalyst is impractical to use. I therefore aimed to create several supports for TiO2, which not only improved the physical durability of the catalyst but also improved the photocatalytic efficiency. Glass wool acted as a wave guide, TiO2 nanofibres served as photoactive supports and zeolites provided an electron sink to decrease hole-pair recombination and to increase contact time between the active species (TiO2) and the target VOC.’

Congratulations to all of our poster winners and to the organisers for an enjoyable symposium.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Open notebook science – memorial symposium for Jean-Claude Bradley

3 July, 2014 - 16:49

Guest post by Antony Williams, chemconnector.com

Jean-Claude Bradley was a chemist, an evangelist for open science and the father of a scientific movement called Open Notebook Science (ONS). JC, as he was commonly known in scientific circles, was a motivational speaker and in his gentle manner encouraged us to consider that science would benefit from more openness. Extending the practice of open access publishing to open data, JC emphasized the practice of making the entire primary record of a research project publicly available online, primarily using wiki-type environments, and in so doing set the direction for what will likely become an increasingly common path to releasing data and scientific progress to the world.

I first met JC as a PhD student at Ottawa University, Canada, when I was the NMR facility manager and was responsible for scientists and students in their research. JC entered my lab one day to ask for support in elucidating the chemical structure for one of his samples and what began that day was a scientific relationship and friendship spanning over two decades. As one of the founders of the ChemSpider platform now hosted by the Royal Society of Chemistry, JC and I reinvigorated our friendship around a drive to increase openness of chemistry data, access to tools and systems to support chemistry, and simply to make a difference.

From too many conversations I know that some of the basic tenets of his views were shunned by many scientists in the early days of his shift towards ONS. Despite people being interested in his approach only a fractional minority of scientists fully supported ONS by being active participants. Through his activities in curating and validating scientific data, engaging chemical vendors in opening some of their datasets, and his demand that everything he did in science be open, he has produced a legacy that will continue to have influence for years to come. Right now, data he released to the public domain is being worked up into open models for release to the community. The Spectral Game that he dedicated efforts to will be supported and enhanced to assist in teaching spectroscopy. In recognition of his work and to celebrate JC’s contribution to science, a memorial symposium will be held in his honour at Cambridge University on 14 July and, of course, is OPEN to everyone.

Jean-Claude Bradley was a scientific leader, an evangelist for open science and a wonderful man. He will be missed but his legacy will survive and flourish.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Making sense of chemical stories

9 June, 2014 - 16:56

Guest post from Lauren Tedaldi, Sense About Science

Have you noticed plastic products labelled as ‘BPA-free’*, heard that Coca-Cola recently removed a specific vegetable oil from its US products** or do you remember the time when there were no blue smarties***? When companies change the way they produce common, long-standing products, we reasonably assume that they have good reasons for doing so: we all know the adage ‘If it ain’t broke, don’t fix it’ right? In reality, companies can be forced to act on the modified version: ‘If enough people think it’s broken— even if there is no evidence that it is—then you’d better fix it if you want to keep selling it.’

Consumer pressure is a force to be reckoned with. Owing in large part to the internet, consumers now have more access to information than ever before. People can search almost every online discussion ever had about a particular product or additive before making a decision. While this has the potential benefit of making people better informed, the flip-side is that the internet and media are littered with misconceptions, myths and pure fallacies, which come up time and time again. For example, the idea that you can live a ‘chemical-free’ life is used by many food-producers; and ‘natural ingredients’ is used as a synonym for ‘good’ in cosmetics and toiletries. But every single thing you come into contact with is made from chemicals: your book, your iPad, yourself! What’s more, not all naturally occurring substances are good for you: the pesticide strychnine, the highly toxic poison for which there is no antidote, is entirely natural – it’s isolated from the strychnine tree.

At Sense About Science, we spend more of our time responding to chemical scare stories, helping journalists pre-empt this narrative, than almost any other single issue. We regularly work with scientists frustrated at the hype around their research. This has changed relatively little over the 10-plus years we’ve been working to tackle chemical myths (Making sense of chemical stories was first launched in 2006). There has been some change: beauty journalists are now more aware and seek advice from a toxicologist or cosmetics scientist more often; and we regularly see detox diets and products debunked across national press and magazines. But we continue to see high profile chemical scares hitting the headlines.

When we see recurring misinformation we respond with our public guides. Teachers and midwives and others who are helping people cut through the noise, as well as journalists and policy makers – who the original guide was written for – have been requesting copies of the guide. So on 19 May 2014 we launched a new edition of Making sense of chemical stories. By capturing insights from the chemists and dieticians who developed the guide, we address six common chemical myths. Armed with these six points, anyone can critique the chemical stories they see:

  1. You can’t lead a chemical-free life
  2. Natural isn’t always good for you and man-made chemicals are not inherently dangerous
  3. Synthetic chemicals are not causing many cancers and other diseases
  4. “Detox” is a marketing myth
  5. We need man-made chemicals
  6. We are not just subjects in an unregulated, uncontrolled environment, there are checks in place

In the guide, we look at common consumer issues to debunk widespread myths. Why are labels such as ‘no artificial ingredients’ or ‘additive free’ seen as good things on our products? Dr Paul Illing, a toxicologist, talks about why additives in food are useful in some cases:

‘Additives have been around for centuries. Many agents that are essential for commercial food preparation and storage have their analogues in the kitchen. Caramel (E150a), a colouring agent, can be made at home by heating sugar. Some additives are clearly beneficial: in 1941 calcium was added to flour to prevent rickets; and antioxidants (necessary to prevent the fats in all prepared foods involving meat or pastry from going rancid) include ascorbic acid (vitamin C, E300) and the tocopherols (vitamin E, E306-309).’

 The guide highlights to consumers that products are not inherently better just because they don’t contain additives.

Professor Danka Tamburic, a specialist in cosmetic science, goes on to explain that we also need certain additives in cosmetics:

‘Most cosmetics and toiletries contain water, hence make a good substrate for growing microbes (eg bacteria or fungi). Proper preservation of cosmetics and toiletries is a necessity, not a choice. Bacterial cells are too small for the naked eye to detect, but if there are enough of them in the product, they may cause skin infections and other problems, especially if the skin is already damaged (cut, bruised or sore). Contaminated products could cause ye infections and, in extreme cases, blindness.’

We urge people, next time you are thinking about paying more for something simply because it’s ‘additive-free’, ‘100% natural’, or ‘detoxifying’, you might want to stop and think whether it’s worth paying a premium for a chemical misconception.

 

The full version of the guide can be found here or visit Sense About Science to see more of our public guides that can help you make evidence-based decisions about the products you choose to buy.

*Bis-phenol A (BPA) is a chemical that is used in manufacturing clear rigid plastic, like water bottles, and there is no compelling evidence that the level of exposure from plastic bottles and packaging is damaging to health

**Coca-Cola has removed brominated vegetable oil (BVO) from its US products (it is not in their European products) owing to consumer pressure. BVO is often incorrectly linked to the toxicity and accumulation data from brominated flame retardants

***Nestlé removed the colouring Brilliant Blue (E133) and replaced it with a natural colourant called spirulina after consumer pressure to go ‘artificial additive-free’. There is no strong evidence for a link between E133 and hyperactivity, and spirulina itself has adverse effects at high concentrations. However, it is often preferred as the natural choice

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

The music of molecules

4 June, 2014 - 15:36

What do molecules sound like? In chemistry, we rarely take advantage of the full panoply of senses available to most humans. Although, as Phillip Ball wrote in January this year that ‘chemistry is the most sensuous science … vision, taste and smell have always been among the chemist’s key analytical tools’, we now sensibly avoid using one of these (molecular gastronomists aside, I’m not aware of a lab that encourages tasting of samples) and rarely, if ever, take advantage of our other senses: touch and hearing.

For researcher David Watts, the idea of listening to organic molecules had been ‘languishing in a notebook’ since he first visualised compounds as tiny stringed instruments. As each molecule has a vibrational signature, it should be possible to convert them to characteristic musical tones. David realised that data from Fourier transform infrared spectroscopy (FTIR) should provide all the necessary information, ‘the frequency and amplitude of absorption in the bonds’, albeit in the wrong format for direct conversion to sound. He designed a second step to create audible sound waves from those vibrations. ‘If an inverse Fourier transform is performed then the FTIR spectrum can be converted into the time/amplitude domain and the vibrations of the molecules heard.’

You can hear his results online at The sounds of chemical molecules. The sounds themselves vary between a telephone tone and the sort of discordant sounds used to create tension in budget science fiction, but making beautiful music was never the aim. This was part curiosity and part proof of principle, but Watts can already see a number of applications.

‘Having the sound of a molecule allows you to perceive it using our auditory sense,’ he told Chemistry World. ‘This alone in my view justifies the experiment.’ Most people, except perhaps those with perfect pitch, would not be able to discern structural/functional information from a static tone, but Watts argues that this isn’t the point – sound adds an additional element to a researcher’s relationship with molecules. ‘Maybe this auditory chemical perception ability can be learnt with practice and be useful for organic chemists as an additional way for them to connect or understand their molecules. A particularly interesting idea is in the auditory monitoring of a chemical reaction, maybe an online FTIR monitoring system could provide reaction progress feedback or offer insight into reactions and their intermediate states. The use of the extra sense of hearing allows you to watch and perform an experiment whilst listening to its progress.’

Giving a voice to a molecule is fairly straightforward. ‘Sounds can be created for any molecule providing a digital spectrum is available,’ says Watts. Although the exact applications are still unclear, it may be wise to start compiling the music of the molecules now, so that we’re ready when those uses do become apparent. ‘In my opinion, the auditory representation of the molecule should be obtained for all molecules and included in online databases as extra information for familiarization purposes and potential future uses,’ says Watts.

As a proof of concept, Watts’ demo proves that accessing an additional sense is well within the realms of possibility. The sine waves he generates may be somewhat grating, and I’m not sure I could bring myself to listen to them throughout the process of a reaction, but they’re just a first step. Next would be to find a waveform that is more pleasing to the ear, or modulate it with additional data. Perhaps temperature could set a rhythm, syncopated by pressure. Soon, we could all be dancing to a molecular melody.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

Schrödinger’s water for the perfect cup of coffee

30 May, 2014 - 11:33

How a computational chemist and an understanding of water helped a coffee shop owner to become the 2014 UK Barista Champion, set to take on the world. Guest post by Chris Hendon.

Christopher Hendon and Maxwell Colonna-Dashwood at Colonna and Smalls, Bath
© tomsmith photography

Brewing coffee might be the most practiced chemical extraction in the world. But within this process there are many variables, all of which dictate the flavour of the resulting coffee. I’ve summarised just a few of them here:

Variable Effect
Bean origin Not all beans have the same chemical composition.
Bean roast The chemical composition of the coffee bean changes throughout the roasting process.
Size of coffee grindings A consistent particle size is important as the higher the surface area, the faster the extraction.
Dry mass of coffee grindings A different extraction composition.
Temperature of extraction The temperature dictates both the rate and composition of the extraction.
Pressure of extraction Has a similar effect as temperature.
Time of extraction Increasing extraction time allows for a greater extraction.
The water This variable is less obvious, but it is clear that the chemical composition of water (i.e. dissolved ions) play a very important role.

 

Analysis of extracted coffee by gas chromatography–mass spectrometry (GC-MS) suggests that the average coffee bean contains upwards of 500 chemical compounds, excluding all of the heavy cellular material. Of this complex array, the bean is primarily a mixture of weakly acidic molecules, and the weaker acids are more desirable. A ‘bad coffee’ can be the result of any combination of the aforementioned variables going awry.

Maxwell Colonna-Dashwood, 2014 UK Barista Champion and co-owner of the specialty coffee shop Colonna and Small’s, in Bath, UK, carefully controls most of these variables. He grinds beans to a consistent particle size, weighs the dry mass, uses a constant temperature and pressure for extraction (which  he dials in for each bean on the day), and defines the extraction by the mass of the extracted coffee. However, it’s almost impossible for him to control the chemical composition of the incident water. Water’s ionic content fluctuates dramatically depending on region and quantity of rain – and it rains a lot in England. The coffee industry has designed some ways to deal with this problem, with filtration units and vague guidelines on what chemical composition to aim for.

The coffee industry has concluded that an ionic concentration of 150–300 parts per million (ppm) is ideal for coffee extraction. But that is inherently flawed; water could contain 150ppm of HCl and would certainly not taste very nice. Conversely, water could contain 150ppm of NaHCO3, which might make you burp as the acid/base reaction in your stomach rapidly releases gaseous CO2. So in search of the perfect coffee, it would be wrong to accept these guidelines without some thought as to the impact of different chemical compositions. Unfortunately, not every local barista has access to an atomic absorption spectrometer (we do). Instead this measurement is often collected (if at all) using an ionic conductivity probe, which makes two absolutely fatal assumptions:

  1. The ratio between dissolved ions (Ca2+, Mg2+, Na+, H+, HCO3-, CO32- etc) is approximately constant
  2. The ionic conductivity of all ions is approximately the same

Both of these statements are incorrect. For instance, in Bath there is much more Ca2+ present than Mg2+ (approximately 300ppm:5ppm, respectively); but in Melbourne the Ca2+:Mg2+ ratio is approximately 20ppm:20ppm. Secondly, the conductivity of an ion is dependent on, among other things, the size and charge of the ion.

Colonna-Dashwood is certainly right in challenging this accepted guideline, but what interaction do these molecules have with coffee particulates and more importantly, does it even matter?

Yes. It matters, a lot.

Christopher Hendon and Maxwell Colonna-Dashwood at Colonna and Smalls, Bath
© tomsmith photography

As is often the case in science, it was an element of serendipidy that brought me into the picture. I’m a computational chemist at the University of Bath, and overheard this discussion while waiting for my coffee. I thought I might be able to contribute to the problem, at very least help to rationalize this in terms of quantum mechanics. I had learned from fundamental chemistry that electron-rich motifs interact with electron deficient motifs. Essentially all molecules in coffee feature a heteroatom (an electron-rich motif), which should interact strongly with dissolved cations in water. Dissolved anions may act as bases, but are not expected to interact with coffee particulates. Thus, water with a high cationic concentration should facilitate a greater extraction of flavorsome notes in coffee. Along with Maxwell and his partner Lesley, we’ve recently published our results.

The world of coffee is an unusual place. As mentioned earlier, Maxwell is the 2014 UK Barista Champion. To be crowned this, you must submit an espresso, a cappuccino and a signature drink to a panel of four judges. You have 15 minutes to do so, and are judged on knowledge of the coffee, your overall presentation and cleanliness, flavour, technical ability and so on. Armed with the knowledge gleaned from our research into the interactions of ions in solutions, I designed different waters for different extractions, to bring out different flavours. This was particularly intriguing for the signature drink which featured an espresso shot mixed with two grape extracts brewed in different water – one with high cation content, one with high base content – to extract different flavours from the grapes. With this victory (for science, I like to think), we are now headed to the world barista championships in Rimini, Italy, June 8–12. I hope that our artillery of scientific knowledge will see Maxwell becoming the 2014 World Barista Champion.

If you find yourself in Bath and fancy a coffee, I would highly recommend you head down to Colonna and Small’s to see and taste the result in person, you’ll be pleasantly surprised. At very least, you can use this story to prove that work really does get done in the coffee shop.

Digg This  Reddit This  Stumble Now!  Share on Facebook  Bookmark this on Delicious  Share on LinkedIn  Bookmark this on Technorati  Post on Twitter  Google Buzz (aka. Google Reader)  
Categories: Education

WebElements: the periodic table on the WWW [http://www.webelements.com/]

Copyright 1993-2011 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.