Our chemical romance – how chemistry touches our lives

The International Year of Chemistry (IYC 2011) is an entire year devoted to the celebration of chemistry. Under the unifying theme “Chemistry – our life, our future,” IYC 2011 reaches across the globe to increase public appreciation of chemistry in meeting world needs, to encourage interest in chemistry among young people and to generate enthusiasm for the creative future of chemistry.

Many people may not realise it, but even while we sleep, our bodies carry out complex chemical reactions, breaking down food substances ingested during the day, to convert them into energy stores required to keep all 50 trillion cells in the body functioning. Chemistry affects almost every aspect of our daily lives, from the fuel in our cars, to the safety of our food and water, the quality of the air we breathe and the cosmetic products we use every day. A range of industries, from food to biotechnology, have grown up using chemistry – and analytical science generally – to provide us with these vital everyday commodities.

But how can we be sure that analytical science, often operating at the very limits of its capability, is deployed accurately and fairly? In the UK, the Government Chemist1 stands as the acknowledged independent guardian of the highest professional standards and the National Measurement Institutes maintain and develop measurement capability for traceable and accurate measurement for use in trade, industry, academia and government.

In a bid to not only raise the awareness of IYC 2011, but also to emphasise that developments in chemistry are essential for sustainability and improvements in every human being’s life, we highlight how chemistry and advances in chemical measurement impact our daily lives, in terms of food safety regulation, consumer product safety, environmental controls, national security and improved medical treatment.

In the UK we are lucky; our drinking water is among the best in the world with the highest safety standards and quality. UK drinking water legislation sets quality standards to ensure that when we turn on our taps, we can be certain of a safe, clean and refreshing water supply. The determination of many compounds including heavy metals in drinking water is imperative to ensure that both public health and legislative requirements are met. Certified reference materials are chemically formulated to be close in matrix composition to water test samples and, produced under a specific ISO Guide (34 for the production of reference materials), provide confidence in the quality of the results obtained, and support the validation of water monitoring procedures.

In the early 19th Century, the deliberate adulteration of food was common practice. Poison¬ous compounds containing lead, copper or mercury were added to sweets to enhance their colour, while it was common practice for bakers to add alum, chalk or powdered bones to bread to give it the desired white appearance. Today, food safety and quality is tightly controlled both by the agrifood industry and government regulation. Nevertheless, issues do still arise which are dealt with by regulators supported by cutting edge chemical analysis. The majority of food adulteration incidents are driven by economic motives, where key ingredients are substituted with a cheaper option, in some cases putting public health at risk. One significant recall incident in recent years involved Sudan I dye, a potentially carcinogenic red dye prohibited for use in food.

A product recall of pizza appeared to be triggered when a private laboratory, on behalf of the manufacturers, found pizza topping sauce to contain the banned Sudan I dye. However, subsequent analysis by local authority public analysts and the manufacturer yielded negative results – so was the carcinogen present or not? The Government Chemist was requested to act as an impartial referee to provide the confirmatory analysis. Based on a limit of detection of 0.02 mg/kg, Sudan I was demonstrated not to be present. Referee analysis, such as this, targeting the safety of food ingredients can help prevent the recall and destruction of satisfactory product, with significant cost savings and impacts on availability across the UK market.

Aflatoxins are a chemically related group of genotoxic carcinogens derived from Aspergillus moulds, which pose a high risk to the safety of imported food produce. They remain prominent in recent EU legislation, setting priorities for official controls, but are undetectable other than by chemical analysis. Many thousands of tonnes of contaminated consignments are rejected by UK Port Health Authorities each year, providing vital protection for consumers. In the overwhelming percentage of cases to date the regulator’s original decision to reject the consignment has been upheld by the Government Chemist.

In the UK, it is estimated that some 1.5 million people have food allergies. In order to improve quality of life, minimise allergy related deaths and reduce the financial impact on the NHS, there is a need for food producers and suppliers to be able to develop ‘allergen free’ product lines, accurately label food products and minimise cross contamination during manufacture.

Advancements in measurement capabilities play an important role in allergen management and the development of high throughput screening technologies. There is considerable analytical activity in this field, but relatively few published or validated methods, causing potentially divergent results and opinion. In a significant development, scientists have recently succeeded in demonstrating a novel reference method using the quantification of the protein allergen egg lysozyme in wine as a model system. The new method has a detection limit of lysozyme protein to below one part per million whilst maintaining an uncertainty of less than 10% but, more importantly, it is a pathfinder approach for international traceability in this complex field.

Although allergens are, almost without exception, proteins, DNA analysis can offer a valuable adjunctive tool when multi-screening several allergenic foods, or when seeking a confirmatory analysis to a protein-based detection technique. Developed during a recent collaborative research project, a DNA-based screening approach for the detection of allergenic nuts in food offers an alternative, reliable and sensitive method for the simultaneous detection of many important nut allergens. It will benefit consumers through improved assurance of food labelling and ultimately reduce adverse reactions to food products.

Tacrolimus is an immunosuppressant drug given to patients after an organ transplant. Due to its narrow therapeutic range, routine therapeutic drug monitoring of tacrolimus concentrations in patient’s blood is essential. Liquid chromatography-mass spectrometry (LC-MS) is being increasingly used in hospital laboratories, although many still use immunoassay techniques. Due to the lack of internationally recognised tacrolimus reference materials and reference methods, these analytical platforms are not standardised and can produce disparate measurement results. In severe cases, this can lead to a patient either receiving an insufficient dosage and rejecting the organ, or receiving a high or toxic dose. The first matrix reference material for tacrolimus in whole blood, certified by high accuracy isotope dilution mass spectrometry (IDMS), is now being developed and will improve confidence in measurement, independent of the analytical platform used. This will ensure optimal patient dosage to the benefit of both patients and healthcare providers.

Selenium occurs in different chemical species which, depending on concentration and structural composition, vary in toxicity and nutritional value. In vitro studies on lymphoma cell lines have shown that low, non-toxic concentrations of particular selenium species can increase the efficacy of chemotherapeutic agents. In order to understand the mechanisms by which this occurs, a combination of data provided by mass spectrometry and biological measurements is required. As some selenium species are very volatile, researchers have developed novel methods to identify and quantify very low levels of selenium species within cells treated with selenium and in the ‘headspace’ above cells in culture. The ability to measure small cellular samples and understand how cells react in the presence of selenium is an important scientific advancement. Translation of the developed methods into the clinic is the next challenge and, if successful, the simple addition of selenium to standard chemotherapy could have a major impact on improving the treatment of cancer.

Throughout our lives, our hair and fingernails accumulate trace elements due to our bodies’ exposure to its environment, diet and lifestyle. Some of these trace elements have isotopic profiles which are unique to their source of origin. Therefore, the variation of the proportion of different isotopes present on a hair sample can be used as a tool to provide information about the geographical movements of an individual. The coupling of a laser ablation (LA) system to a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) enables the detection of subtle changes in isotope ratios so that a chronological record of isotopic variations up to the time of sample collection can be obtained. If proved successful, this method may be used, in combination with other approaches (e.g. DNA analysis), by forensic scientists to map geographical variations for a wider population, offering the potential ability to track the movements of individuals, including international crime suspects and crime victims.

Current immunoassay analysis of steroidal hormone markers in saliva and serum of athletes is being extended to include cytokine analysis through the use of next generation electrochemiluminescence detection platforms. This will enable the optimisation of an approach for correlating stress indicators with muscle tissue physiology and function to assess athlete performance and provide a basis for wider health and well-being indicators. Working with instrument manufacturers, scientists are also developing a portable, trackside detection platform that could provide real time data to enable trainers to tailor athlete’s training regimes, thereby ensuring maximum performance and improving injury recovery time.

Food supplements are regularly used by elite athletes in the build up to a sporting event to improve fitness and performance. However, to ensure they do not inadvertently consume supplements which may contain substances banned by the World Anti-Doping Agency, athletes rely on the Informed-Sport testing programme. The Informed-Sport logo which can be found on the packaging of many energy drinks and food supplements, assures athletes that the products have undergone rigorous checks and testing to ensure that they are not contaminated with banned substances and are safe to use.

The European Union’s commitment to a cleaner environment requires low level sulphur content for road transport fuels. Detecting sulphur at low levels has required the development of more sensitive methods of analysis. An important issue for the oil industry has been the lack of certified reference materials able to provide reference values of sufficiently small uncertainty for reliable verification of results at low levels. The development of certified reference materials to determine sulphur in fuel allows laboratories to develop and validate methods to accurately measure low level concentrations of sulphur. This enables oil companies to optimise their sulphur extraction processes and demonstrate compliance with increasingly stringent legislative requirements.

Competition for land use of biofuel versus food and feed production highlights the need for sustainable raw materials. EU policies on sustainable development, climate protection and food production require detailed information on the origin of marketed biofuels. First generation biofuels are typically vegetable oil, biodiesel and bioethanol produced from raw materials such as rapeseed, sunflower, sugar cane, animal fat and bio-waste. The determination of the geographical and biological origin of biofuels will help ensure that they come from a sustainable source. Research is being undertaken to discriminate between biofuels of different origin by using isotope ratio mass spectrometry. Building on previous research to demonstrate the origin of food using carbon, hydrogen and oxygen isotope ratio measurements, methods are being adapted to determine the origin of raw materials in biodiesel.

The UK has clear strengths in industrial sectors heavily reliant on chemistry and chemical measurement such as the pharmaceutical and biotechnology sectors. LGC, as the UK’s designated National Measurement Institute for chemical and bioanalytical measurement, sustains such sectors by upgrading the measurement and standards framework to meet emerging needs, enabling the results of emerging measurement techniques to be exploited by industry, and accepted by regulators and markets worldwide.

World-class measurement science supports the global economy by providing accurate, traceable and comparable measurement results. The Government Chemist at LGC applies sound analytical science in the public interest, providing independent expert evidence and advice to Government and industry.

References: 1 Government Chemist Review 2010

Author: Louise Dean

Contact: e: louise.dean@lgcgroup.com w: www.lgcgroup.com w: www.chemistry2011.org