Sustainability and Environmental Awareness in the World of Separation Science

In this written interview with Dwight Stoll, LCGC Columnist and Professor of Chemistry at Gustavus Adolphus College in St. Peter, Minnesota to address the pressing issues of sustainability and environmental awareness in separation science. We refer to sustainability in the context of the development and utilization of analytical methods and instrumentation that minimize environmental impact, conserve resources, and promote long-term ecological balance while achieving efficient separation and purification of sample molecules. Sustainability encompasses the optimization of processes, materials, and energy usage to ensure minimal waste generation, reduced energy consumption, and increased reusability of separation chemical agents, instrument components, and instrument platforms.

Dwight R. Stoll is the editor of “LC Troubleshooting.” Stoll is a professor and the co-chair of chemistry at Gustavus Adolphus College in St. Peter, Minnesota. His primary research focus is on the development of 2D-LC for both targeted and untargeted analyses. He has authored or coauthored more than 99 peer-reviewed publications and four book chapters in separation science and more than 150 conference presentations. He is also a member of LCGC’s editorial advisory board.

What are some technical developments that are facilitating green analytical chemistry technologies?

I am bullish on the development of closed-loop automation and smart algorithms to streamline method development for LC and 2D-LC. I think there is tremendous potential to reduce the material and energy intensiveness by reducing the amount of trial-and-error experimentation that is done in the method development process. I think we (as a community) have the know-how and component parts to really bring this into the mainstream, but it will take a concerted effort among industry and academic scientists and instrument manufacturers to make it a reality for the next generation of LC practitioners. Some recent papers in this vein are references (1,2).

Can you discuss some successful sustainability initiatives or projects you have studied or implemented?

We are gradually increasing the share of research in my group that involves automation tools and approaches for method development. We have also invested a great deal of time (and money) into an approach to high throughput retention measurement. I believe that widespread availability of high quality retention data will ultimately be a key to unlocking the potential of automation in everyday use of LC. Some recent papers along these lines are references (3,4).

In what ways does sustainability influence decision-making processes for you in particular and for separation scientists in general?

My laboratory is not a very high volume operation, so it does not influence our thinking too much. However, just in the past couple of years I feel there has been a noticeable change in how industry leaders talk about sustainability. At conferences they are talking about “Net Zero by 2050” and the “circular economy”, and I think this is really driving changes in the way folks approach research topics.

What role does innovation play in advancing sustainability practices in separation science?

I think innovation will play the most important role. At the HPLC 2023 meeting in Germany last summer, an industry leader made the statement that the key to reaching net zero emissions and the circular economy is to accelerate the pace of innovation. And I think the same is true when it comes to practicing analytical chemistry (and specifically LC) in more sustainable ways. The same old ways we’ve been doing things won’t cut it going forward. We need new ideas.

Can you discuss any specific challenges or barriers you've encountered in implementing sustainability initiatives, and how have you addressed them?

I am not an expert on sustainability, so I’ve been reaching out to industry for direction on what we, as researchers, should prioritize. Unfortunately I have not heard clear answers on direction and priorities. So, I think this is currently a challenge (barrier). The clearer are the objectives for what we are trying to achieve, the faster we can identify opportunities, and start down the path toward those goals.

What are some emerging trends or technologies that you believe will have a significant impact on sustainability in the future?

The miniaturization of LC instrumentation is a really interesting trend. Over the last few years several groups have shown that good LC separations can be done with equipment that has a really small physical and energy footprint. It seems to me the big question now is how much of a share of all applications can be converted to this lower cost (material, capital, equipment) approach.

Looking ahead, what do you see as the biggest opportunities and priorities for advancing sustainability for chromatography in the next decade?

It seems like there are some real opportunities to implement mobile phase solvents as alternatives to acetonitrile. These will not work for all methods right away, but I think some methods could be converted with relatively little effort, and with great benefit to the environment.

References (5–8) are provided for supplementary reading.

References and Further Reading

(1) Bos, T. S.; Boelrijk, J.; Molenaar, S. R.; van’t Veer, B.; Niezen, L. E.; Van Herwerden, D.; Samanipour, S.; Stoll, D. R.; Forré, P.; Ensing, B.; Somsen, G. W.; Pirok, B. W. J. Chemometric Strategies for Fully Automated Interpretive Method Development in Liquid Chromatography. Anal. Chem. 2022, 94 (46), 16060–16068. DOI: 10.1021/acs.analchem.2c03160. 

(2) Aldine, F. N.; Singh, A. N.; Wang, H.; Makey, D. M.; Barrientos, R. C.; Wong, M.; Aggarwal, P.; Regalado, E. L; Ahmad, I. A. H. Improved Assay Development of Pharmaceutical Modalities Using Feedback-Controlled Liquid Chromatography Optimization, J. Chromatogr. A 2024, 464830. DOI: 10.1016/j.chroma.2024.464830.

(3) Kempen, T.; Dahlseid, T.; Lauer, T.; Florea, A. C.; Aase, I.; Cole-Dai, N.; Kaur, S.; Southworth, C.; Grube, K.; Bhandari, J.; Sylvester, M.; Schimek, R.; Pirok, B.; Rutan, S.; Stoll, D. Characterization of a High Throughput Approach for Large Scale Retention Measurement in Liquid Chromatography, J. Chromatogr. A 2023, 464182. DOI: 10.1016/j.chroma.2023.464182.

(4) Stoll, D. R.; Kainz, G.; Dahlseid, T. A.; Kempen, T. J.; Brau, T.; Pirok, B. W.; An Approach to High Throughput Measurement of Accurate Retention Data in Liquid Chromatography, J. Chromatogr. A 2022, 463350. DOI:10.1016/j.chroma.2022.463350.

(5) Kannaiah, K. P. et al. Integrative AQbD, Up-to-date Greenness, and Whiteness Tools for Evaluation of a Sustainable RP-HPLC Method Used for Simultaneous Separation of Triple Antihypertensive Combination Therapy as a Model. Sustain. Chem. Pharm. 2023, 36, 101288. DOI: 10.1016/j.scp.2023.101288 

(6) Yenduri, S.; Sulthana, H.; Koppuravuri, N. P. Sustainablity Evaluation of Existed HPLC Based Analytical Methods for Quantification of Amlodipine Besylate and Telmisartan Using RGB Model: A Whiteness Approach. Green Anal. Chem. 2023, 100074. DOI: 10.1016/j.greeac.2023.100074 

(7) Michael, A. M.; Lotfy, H. M.; Nessim, C. K. Greenness Profile and Whiteness Assessment of the Stability-indicating HPLC Method for the Assay of Levetiracetam. Microchem. J. 2023, 190, 108669. DOI: 10.1016/j.microc.2023.108669 

(8) Imam, M. S.; Abdelrahman, M. M. How Environmentally Friendly is the Analytical Process? A Paradigm Overview of Ten Greenness Assessment Metric Approaches for Analytical Methods. Trends Environ. Anal. Chem. 2023, e00202. DOI: 10.1016/j.teac.2023.e00202