What will you be doing?
Passive sampling is a promising technique for both air quality monitoring and for determining personal exposure to (semi) volatile organic components ((s)VOCs). The samplers are inexpensive, easy to use, do not need electricity and maintenance and make no noise. Recently, new sampling media, such as PDMS (silicone rubber), have entered the market, which means (1) the samplers are smaller and can therefore be used on a large scale and (2) the use of advanced 'direct' analysis techniques (without sample preparation), such as Direct Thermo Desorption GCMS (DTD-GCMS) becomes possible. At present, the PDMS samplers in air are mainly used as a qualitative screening method, while in water these samplers are already included as a fully-fledged quantitative technique.
A quantitative calculation model is already available in water; for air this has yet to be developed, whereby the building blocks of the "water model" can be used as a basis. In principle, all (s)VOCs can be measured including the more polar substances, but this will have to be tested for each substance (group). The method has recently been validated for the substance groups: PAH, PCB, OPE, phthalates, OCP, several pesticides, musk and BFR. The extent to which other substances of very high concern (SVHC) can also be measured will still have to be investigated.
The uptake rate of substances depend on the temperature and air speed along the sampler. Recently, the correlation between uptake rate and air speed was determined by means of a laboratory study, and the temperature dependence is already well described in the literature. However, the exact determination of the air speed along a sampler remains a critical point. Two methods are available to solve this problem: (1) applying a housing to dampen the fluctuations in the air speed along the sampler and (2) spiking of labeled components on the sampler at the start of the sampling period. Namely, the decrease of the concentration of labeled components in the sampler is equal to the uptake of substances.
In this internship the passive sampling technique with PDMS will be explored as a quantitative method for the determination of (s)VOCs. One or more of the following activities are foreseen:
- Development of a quantitative mechanistic calculation model for air, (1) based on uptake rate and partitioning coefficients and (2) based on the decrease of spiked labeled standards
- Testing of several mini-sampler housings by field experiments
- Exploration of the passive sampling technique for ZZS substances based on chemical and physical properties, such as molecular weight, hydrophobicity, partitioning (Kow, Koa), vapor pressure, solubility, density
- Exploring the "direct" DTD-GCMS technique for PDMS and determining performance characteristics
What do we require of you?
Our ideal candidate is a last year bachelor (HBO) or master student with a (analytical)chemical, environmental or closely related background, a multidisciplinary and scientific interest and preferably with an affinity for analytical method development and not afraid of large amounts of data and calculations.
- The internship start date will be determined in consultation with the candidate
- The internship has a minimum duration of 5 months and a maximum duration of 9 months
What can you expect of your work situation?
TNO is an independent research organisation whose expertise and research make an important contribution to the competitiveness of companies and organisations, to the economy and to the quality of society as a whole. Innovation with purpose is what TNO stands for. With 3000 people we develop knowledge not for its own sake but for practical application. To create new products that make life more pleasant and valuable and help companies innovate. To find creative answers to the questions posed by society. We work for a variety of customers: governments, companies, service providers and non-governmental organisations. Working together on new knowledge, better products and clear recommendations for policy and processes. In everything we do, impact is the key. Our product and process innovations and recommendations are only worth something if our customers can use them to boost their competitiveness.
In the unit of Circular Economy & Environment, applied research is carried out in creating a healthy and sustainable living environment and climate. Within the department of Environmental Modelling, Sensing & Analysis (EMSA) we study complex questions about the presence, mitigation and effects of (potentially) harmful substances. Our well-equipped laboratories are able to determine the precise composition and amounts of substances in the air and in water, soil, blood and (consumer) products.
to read more about EMSA.
What can TNO offer you?
You want to work on the precursor of your career; a work placement gives you an opportunity to take a good look at your prospective future employer. TNO goes a step further. It’s not just looking that interests us; you and your knowledge are essential to our innovation. That’s why we attach a great deal of value to your personal and professional development. You will, of course, be properly supervised during your work placement and be given the scope for you to get the best out of yourself. Naturally, we provide suitable work placement compensation.
Has this vacancy sparked your interest?
Then please feel free to apply on this vacancy! For further questions don’t hesitate to contact us.
Note that applications via email and third party applications are not taken into consideration.
Contact: Sieger Henke
Phone number: +31 (0)6-114 32731