Development of a Novel Single Droplet Mass Spectrometry Approach to Investigate Interfacial Photochemistry in Aerosol Droplets

Applications are invited for a 4 year PhD studentship starting in Autumn 2023 as part of the EPSRC CDT in Aerosol Science 

Project description  

One unique aspect of aerosols is their high surface area-to-volume ratios. For instance, a litre of water contains only a few square centimetres of surface area. However, if that litre of water were aerosolised to form 1 µm diameter droplets, the total surface area increases by several orders of magnitude to a value similar to that of a football pitch. Consequently, the aerosol-air interface has emerged as key to driving aerosol chemistry. Recent studies showed that chemical reactions can be accelerated more than a million times in aerosols relative to macroscopic solutions. Reactivity at the aerosol-air interface is a potential explanation for these observations. 

However, vanishingly few approaches exist to measure chemical composition at the aerosol-air interface. Development of a completely novel approach to study this interface will open up opportunities to investigate the unique chemistry inherent in aerosols. The first objective is to develop a field-induced droplet ionisation approach for falling droplets generated from a microdroplet dispenser. As the droplets fall, a high electric field will be induced across two plates causing a distortion in droplet shape followed by droplet breakup. Initially, large (>80 μm diameter) uncharged droplets will be studied, gradually working towards smaller droplets with some net charge. The second objective will be to couple the FIDI approach with a charged droplet (5-30 μm) in an electrodynamic trap. We have already built electrodynamic traps that reproducibly levitate charged droplets in this size range. Then, the progeny droplets will be directed into a mass spectrometer using a variation on the experimental setup we have already constructed to perform droplet assisted ionisation on levitated droplets. The sensitivity and surface selectivity of the approach will be evaluated using droplets containing standards including surface active (e.g. sodium dodecyl sulfate, Triton) and non-surface active (angiotensin, cortisol, ammonium sulfate) test compounds. Lastly, the photochemistry of atmospherically relevant molecules like palmitic acid will be explored, with an aim to identify chemical pathways of interfacial photochemistry and how interfacial and bulk photochemistry may converge to drive secondary chemistry in droplets. These experimental results will help inform chemical models about the fates of surface-active atmospheric compounds and elucidate how chemical reactivity can be altered by the high surface area-to-volume ratios in microscopic systems. The experimental approach is expected to be useful for answering science questions well beyond the realm of atmospheric chemistry. 

Dr Bryan Bzdek would be pleased to discuss this project further with interested candidates:  [Email Address Removed] 

About the Centre for Doctoral training in Aerosol Science 

Aerosol science is crucial to disciplines as broad ranging as transmission of disease, drug delivery to the lungs, climate change, energy and combustion science, novel materials, and consumer and agricultural products. 

An aerosol is any collection of particles dispersed in a gas. The CDT brings together a multi-disciplinary team of 80 post-graduate students and academics from 7 UK universities spanning the physical, environmental and health sciences, and engineering. Our aim is to tackle the global challenges in which aerosol science is key. 

Further details are available from our website: https://www.aerosol-cdt.ac.uk/ 

Doctoral Training in Aerosol Science 

During your doctorate, you will learn to research in diverse multidisciplinary teams, gain an advanced understanding of the core physical science of aerosols, and collaborate with industrial and public sector partners, equipping you to undertake ground-breaking research in aerosol science.  

During the first 7 months of your PhD, you will join the CDT cohort based at the University of Bristol. Core training in aerosol science, research methods, professionalism and translation will be delivered by Team Based Learning. You will then undertake a short research project at your home or partner institution before starting your PhD research. You will gain experience outside academia in a placement with an industrial/public sector partner in Year 2 or 3. 

More Information and How to Apply 

Candidates who aspire to work in a multidisciplinary field, and hold or will achieve a minimum of an upper second-class undergraduate degree in any of these areas are encouraged to apply: chemistry, physics, biological sciences, life and medical sciences, mathematics and computer science, chemical and mechanical engineering, pharmaceutical and environmental sciences. 

Visit our website:                                              Contact us: 

https://www.aerosol-cdt.ac.uk/                     [Email Address Removed] 

Application Deadline: 

Shortlisting for interview will take place after the deadlines below. We encourage early application to ensure the greatest availability of studentships. 

Shortlisting deadlines: 

9am, Monday 12th December 2022 

9am, Monday 9th January 2023 

9am, Monday 30th January 2023 

9am, Monday 20th February 2023 

Shortlisted candidates will be invited to take part in the CDT Interview & recruitment process, where you will have the opportunity to meet with potential PhD supervisors and narrow your shortlist to your preferred three projects. You will also meet with members of the CDT to explore whether the CDT in Aerosol Science is a good fit for you, and ask questions. 

Diversity and Inclusion  

We are committed to furthering issues of equality, diversity and inclusion and are keen to attract the most highly talented individuals from diverse backgrounds. The needs of individuals will be accommodated during the recruitment process and while studying with the CDT. Further information on our commitment to equality and diversity can be found on our website.