NTS: an Analytical Goldmine
Non-targeted screening takes us outside of the box to present numerous opportunities – and offer untold rewards. Here’s how we’re increasing access to the challenging hardware and software workflows required.
Stefan Bieber | | Longer Read
My interest in non-targeted screening (NTS) began very early in my academic career. I completed my undergraduate thesis as part of Thomas Letzel’s research group at the Technical University of Munich; they had been using NTS for some years before, and had considerable experience in the field. It was there I saw the potential to apply NTS in many different research projects, such as red wine (1), beer or waste- and surface waters (2) – and also realized how much I enjoyed sharing my analytical expertise with others. Combining a passion for NTS with the joy of teaching seemed – to me – the perfect opportunity.
A holistic solution
At the time, many labs and institutions wanted to implement NTS, but they did not have the time or resources to establish their own workflows. Together, Thomas and I created a comprehensive business concept, covering knowledge transfer and support for advanced analytical topics, including polarity-extended separations like supercritical fluid chromatography (SFC), as well as education in basic analytic topics (GC- and LC-MS, for example) for non-academic employees in analytical labs.
Several years later, we cofounded AFIN-TS, which provides services to numerous organizations: instrument vendors, separation phase vendors, analytical companies, software engineers, and educational facilities in numerous fields. Our philosophy is simple – to provide a comprehensive and holistic solution to consumer needs, not only restricted to NTS.
To achieve this, we combine broad and efficient analytical techniques with robust and reproducible data evaluation workflows. We use polarity-extended separation techniques to isolate non-polar to very polar compounds in one run, and couple these with different ionization techniques and sensitive MS – all optimized through chemometrics. The subsequent data evaluation is then expressed in a tailored workflow – which is important, because data evaluation is both time-consuming and a significant source of potential error.
Many tools are available for data evaluation, but none can solve every problem – not yet, at least. We like the idea of combining existing tools to create a comprehensive data evaluation system that is fit for purpose; the online NTS platform FOR-IDENT represents significant movement towards the realization of this concept, and we are now extending it further. Initially, FOR-IDENT was just applicable to LC- and SFC-MS-derived data, but – thanks to our partners – we have been able to eliminate this restriction. We’ve adjusted our data evaluation workflows and strategies accordingly, and launched last year our ready-to-use GC-Soft-Ionization-MS NTS system with comprehensive data evaluation support, which we continue marketing now.
What makes a business tick?
Of course, there are many important things to consider when evaluating what makes a business successful. In addition to a well-thought-out business concept and competent partners, you must also be willing to learn a lot of new things. We offered a broad range of services from the start, because we would never have been able to pay our bills with NTS alone. However, the combination of NTS consulting, seminars, training and LC or SFC method development services – as well as the support we offered in general analytics and molecule identification – has allowed us to move forward.
When starting any business, the most important consideration is funding. As a consulting company, we do not fit the description of a typical start-up; we were not marketing scalable products with mappable growth potential. Thus, financing our business by venture capital or business angels was almost impossible. We were fortunate to find some extraordinary partners who supported our ideas and concepts from the beginning, giving us the freedom to grow in a sustainable way and building our business step-by-step. And still, remain open to new potential partners wanting to collaborate and help evolve NTS further.
NTS for all
Our mission? To increase the applicability and use of NTS, and to transfer the required analytical knowledge in an effective and sustainable way. We see ourselves as a professional consulting, education, and research institute – and that doesn’t apply only to NTS, but to a wide array of advanced analytical techniques. As a PhD student, I worked a lot with SFC – a technique that is not widely established but can be extremely powerful in NTS. To increase its usage, knowledge of the technique must be shared. There’s a clear lack of skilled and trained staff in many institutions; we offer a portfolio of seminars and advanced training that we hope will go some way to countering this current lack of know-how. Demand for training is one of our success metrics – if there is no more demand for education on a particular topic, then it will have become a widely applied strategy. Our goal will have been met.
I’m very optimistic about the future of NTS generally, and our business in particular. In 2020, we are creating a framework with our partners to further extend what we offer in terms of teaching. Within the next three years, our main topics will be tailor-made NTS solutions, the programming of analytical platforms, and sustainable knowledge transfer. Long-term, our own research interests will shift towards holistic concepts, with increased integration of advanced data evaluation, such as machine learning and neural networks. There’s much potential and demand for automation in data evaluation, while the need for NTS is increasingly obvious in many analytical areas, including metabolomics (3), environmental analysis, and pharma. In the next few years, however, I believe food analysis will lie at the forefront of NTS development – the community using NTS to detect food fraud and to identify food contaminants (such as non-intentionally added substances) only grows as time goes on.
Of course, there are plenty of challenges to overcome. We will need to find ways to simplify data evaluation; combined with different tools and platforms, we must develop robust workflows. To truly master this, we need NTS users from various fields talking with MS vendors. We need to collaborate to address the challenges and develop clever solutions. So, I end with a simple message to all NTS users: let’s get together!
Mass Spectrometric Non-Targeted Screening 101
NTS is an unfocused but comprehensive analytical strategy based on MS. It requires the separation of a sample and subsequent detection of separated compounds by high-resolution and accurate tandem-MS to record fragment spectra signals.
All analytical steps are adjusted to detect as many compounds as possible. Special attention must be paid to the choice and optimization of individual analytical techniques, and data evaluation is conducted using specific software tools for peak finding and feature alignment. Ideally, these tools combine all the signals produced by a compound, including isotopes and adducts. These features consist of the accurate mass of the detected compound, its retention time, and – if available – the fragment spectrum. Using representative background measurements, one can then identify sample-relevant features.
NTS has applications in nearly every analytical field: investigating the origin of red wine; identifying trace organic compounds in surface water; finding the cause of product alterations, and many more. The procedure is the same – the difference is the subsequent data evaluation strategy. NTS allows you to learn so much more about samples and their background, and to work – as they say – “outside of the box.”
FOR-IDENT (water.for-ident.org) is an online software platform for MS NTS applications that was created as part of a research project funded by the German Ministry of Education and Research. It combines compound databases and data evaluation tools in powerful NTS workflows. The databases contain anthropogenic (water relevant) compounds (STOFF-IDENT) or biogenic compounds originating from plants (PLANT-IDENT). Users can upload their NTS data to FOR-IDENT and apply the integrated workflows, using MS, MS/MS and retention time information for the identification of candidate molecules. This open-access approach ensures that companies, authorities and scientific institutions can access reproducible and reliable NTS workflows free of charge and without any barriers.
- G Greco et al., “Serial coupling of reversed-phase and zwitterionic hydrophilic interaction LC/MS for the analysis of polar and nonpolar phenols in wine”, 36, 1379 (2013). DOI: 10.1002/jssc.201200920
- S Bieber et al., “RPLC-HILIC and SFC with Mass Spectrometry: Polarity-Extended Organic Molecule Screening in Environmental (Water) Samples”, 89, 7907 (2017). DOI: 10.1021/acs.analchem.7b00859
- R. Wahman, J. Grassmann, P. Schroeder and T. Letzel: Plant Metabolomics via RPLC-HILIC-TOF-MS. LCGC N. America and Spectroscopy supplement: Current Trends in Mass Spectrometry (2019).