Benchtop NMR spectroscopy can accurately analyse pyrolysis oils
A team of researchers at Aston University has demonstrated that benchtop spectrometers are capable of analysing pyrolysis bio-oils just as well as far more expensive, high-field spectrometers.
Bio-oils resulting from the intense heating (pyrolysis) of industrial or agricultural by-products, are increasingly seen as potential alternatives to fossil fuels. But the stability and consequent treatment of these bio-oils depends entirely on their composition; and since they are often mixtures of many dozens, or hundreds, of different compounds, analysing such complex mixtures is not simple – or cheap.
Dr Robert Evans, Senior Lecturer in Physical Chemistry at Aston University, explains: “The composition of any pyrolysis bio-oil is absolutely key to future use. For example if there are oxygen-containing chemicals in the oil, that will make the oil more corrosive and it will be more unstable. So in particular we need to know if carbonyl groups are present – where oxygen and carbon atoms are bonded together – as these can have a major impact.”
A leading method of analysis is high-field nuclear magnetic resonance (NMR) spectroscopy, which gives a detailed breakdown of the identity and concentration of chemical species present in any sample. However these large high-field NMR spectrometry machines cost in the range of £600,000-£10million and require a supply of expensive cryogens and solvents, so are generally only found in the very biggest research facilities.
The team at Aston, led by Dr Evans, set out to see if ‘low-field’, or benchtop, NMR spectrometers, could analyse pyrolysis oils well enough to produce the necessary detailed information. Benchtop NMR spectrometers use permanent magnets, which don’t require cryogenic cooling, so cost much less to purchase and maintain. However, using lower strength magnets comes at the cost of lower sensitivity and poorer resolution. While they can find some use as research instruments, they are also commonly found in teaching laboratories.
The study, carried out with collaborators at the University of Tennessee, tested pyrolysis oils produced from a number of different plants, and compared the results from benchtop spectrometers to both high-field spectrometers and other methods of analysis. They found that the benchtop machine estimates compared favourably with titration analysis for overall carbonyl content, as well as matching high-field spectrometry for the specific identification of carbonyl groups such as ketones, aldehydes and quinones.
Dr Evans said: “Despite the known limitations of benchtop spectrometers, a very similar quality of NMR data could be obtained for these samples, enough to accurately estimate concentrations of different classes of carbonyl-containing species. Using benchtop spectrometers will make NMR analysis of pyrolysis oils much simpler, cheaper, and more accessible to a wider range of different users.”
Quantitative Low-Field 19F NMR Analysis of Carbonyl Groups in Pyrolysis Oils is published online today in ChemSusChem, a journal of Chemistry Europe.
Multiple factors delay timely endometriosis diagnosis, study shows
New research from Aston University has uncovered reasons why endometriosis, one of the most common and debilitating gynaecological conditions, takes an average of 8 years to be diagnosed by medical professionals.
Reviewing qualitative studies from the past 20 years, the researchers found a range of contributing factors including: a continuing stigma around periods; society’s normalisation of menstrual pain; and a lack of medical training about the condition.
Endometriosis, which affects 10% of women globally and 1.5 million women in the UK alone, is caused by endometrial (womb) tissue growing outside the womb. It’s extremely painful, exhausting, interferes with daily life and can lead to infertility if untreated.
The researchers found that women in the studies often weren’t sure if their pain was unusual or severe enough to seek treatment. When they did, some found that their GP was doubtful, or even dismissive of their symptoms. GPs in two of the studies themselves admitted that they found it difficult to differentiate problematic pain from ordinary menstrual symptoms.
Dr Sophie Davenport, who led the research and is now working as a doctor in the NHS, says: “Society has traditionally normalised period pain, so we need to rethink what constitutes ‘non-normal’ periods. If symptoms are affecting daily life, where the woman is not going to work or school, or unable to carry on a social life, that’s a clear sign that medical intervention is needed”.
Many GPs in the studies reviewed mentioned a lack of knowledge about endometriosis, with some saying they’d had scant training in medical school about it. Endometriosis symptoms can vary widely and overlap with other common conditions, so the signs can be difficult to spot.
Dr Davenport says: “Given the numbers of women affected, we think there should be additional, mandatory training about menstrual conditions during medical school. At present, as little as 4 weeks out of 5 years of medical training may be spent on gynaecology; and during that time, endometriosis may barely be mentioned. Given that 1.5 million women in the UK are affected, we think it’s time to prioritise this.”
Even if suspected, the definitive method of diagnosis has been by laparoscopy under general anaesthetic, so some practitioners have been reluctant to order such an invasive procedure. However recent ESHRE guidelines now recommend a two-step approach in which treatment is started more quickly, based on clinical suspicion and MRI/ultrasound imaging, rather than waiting for laparoscopic findings. Supervising author Dr Dan Green, Senior Teaching Fellow at Aston University’s College of Health and Life Sciences, adds: “It will be interesting to see if these new ESHRE guidelines affect the existing time to diagnosis, and can improve patients’ experiences in future.”
Emma Cox, CEO of Endometriosis UK, comments: “We hear many stories at Endometriosis UK evidencing the points this research highlights. The study underlines once more that those with suspected and diagnosed endometriosis are being consistently let down. I urge Government to use these findings to drive forward real action towards ensuring greater, faster and easier access to medical professionals with a specialist interest in endometriosis across England, Scotland, Wales and Northern Ireland.”
She continues: “It’s important that women experiencing chronic pelvic pain or other symptoms of endometriosis speak to their GP, and when they do they should expect to be listened to, believed and understood. We have heard many stories of such symptoms being shrugged off as ‘normal’, ‘not serious’ or ‘just part of being a woman’. These attitudes are changing, but sadly we still have some way to go.”
‘Barriers to a Timely Diagnosis of Endometriosis: A Systematic Review and Qualitative Synthesis’ will be published in ‘Obstetrics & Gynaecology’ on July 6 2023.