Earth Day 2026: The Balancing Act of ”Greenness” and Analytical Performance

How do you currently balance “greenness” with analytical performance in your chromatographic methods?

I must admit that this is not an easy task. As an analytical chemist, I feel that I should prioritize analytical performance. Speed in both analysis and sample preparation increase productivity in the lab. High recovery rates, lower limits of detection, robustness, high precision and accuracy etc are among the main figures of merit to assess the performance of the analytical method. Legislation criteria and validation requirements must be met. But all these not at any cost. As human beings, we should also think about the future of the planet. The planet that our children and grandchildren are going to inherit and already suffers from the negative effects of many bad practices in the past. So, with this in mind, I try to adjust the method so that it is as green(er) as possible, while the performance characteristics lay within the acceptable/required ranges.

Which sustainability or greenness metrics do you actually use in practice—and why those specifically?

Τhere are plenty of greenness metric tools available, and as happens in any case, each one possesses its own characteristics, advantages and drawbacks.

In the early years after the introduction of the Green Chemistry concept¹, NEMI² and Analytical Eco-Scale³ were the first tools to be applied to evaluate the potential negative environmental impact of the method.NEMI is a qualitative metric, while Analytical Eco-Scale provides a numerical score without a visual presentation.Over the years more greenness metric tools have been designed, progressively improved and are increasingly being applied by most analytical chemists. Amomg them Green Analytical Procedure Index (GAPI)⁴, and Analytical GREEnness tool (AGREE)⁵ have been proposed and widely accepted by analytical chemists.

The first versions have been subsequently improved. For example, AGREEprep⁶ was introduced to evaluate the greenness of the sample preparation process. In a similar concept, Complementary Green Analytical Procedure Index (ComplexGAPI)⁷ was designed to expand GAPI by adding additional fields pertaining to the processes performed prior to the analytical procedure itself.

Since, both GAPI and ComplexGAPI provide no numerical value thus making them not quantitative to clearly indicate the weakest points of the procedure, modified versions were later designed. The modified GAPI tool (MoGAPI)⁸ and the ComplexMoGAPI⁹ are advanced versions of GAPI and ComplexGAPI respectively, using faster and more user-friendly software. The implementation of the total score in the modified versions provided an overall assessment of the method’s greenness, while also facilitated visualization and comprehension.

AGREE is the most widely used metric. Its main advantage is that it takes into account all 12 Green Analytical Chemisyty (GAC) principles¹⁰, making the assessment more comprehensive. But it also bears a limitation of subjectivity and/or confusion due to the choice of a weighing factor for each parameter. Though the latter can be overcome, if equal weighing factors are applied.

So, by looking at the literature, we can roughly say that currently two main trends have prevailed in most publications. These include: 1. The AGREE and/ or AGREEPrep tools and 2. the Green Analytical Procedure Index (GAPI)/ Complementary Green Analytical Procedure Index (ComplexGAPI)/MoGAPI/ComplexMoGAPI approaches.

In both cases application software is user-friendly, and freely available as open-source and downloadable. I would equally recommend them. Though in practice, I am more familiar with the use of the GAPI group. Since my research focuses on sample preparation by using novel materials, ComplexMoGAPI covers all the necessary evaluation aspects.

Do you think the proliferation of metric tools has improved method development—or created confusion (“Tower of Babel” effect)?

I am happy to see that you have adapted the term “Tower of Babel” effect, which I suggested in a Commentary recently published in Green Analytical Chemistry.¹¹

As I have written in this manuscript: Apparently, over time a proliferation of very often partially overlapping metric tools has been observed. Definitions and calculation approaches are identical or similar to a great extent, yet finally this diversity in their application yielded a new Tower of Babel, where analytical chemists could not compromise to a single use. Moreover, many researchers felt that each metric tool left a gap regarding several aspects based on their own experience or field of application and thus they opted to create a new tool. And this is a never-ending story, which hence must be slowed down and maybe changed in orientation. What is now more necessary than ever is a harmonization in the use of the already existing tools.

What I mean is that in the course of time scientists, in their effort to fill in the gap of a missing parameter, decide that new metrics are necessary, so they proceed in designing new tools, which in most cases are similar to existing ones with a ca 70–80% similarity in concept. On the other hand, the analytical scientist that wishes to evaluate their newly developed method is confused about which one to choose. Among many choices it is difficult to decide which one is more comprehensive or suitable to fit their requirements.

At what stage of chromatographic method development should sustainability metrics be applied?

This is a very good question.

To my opinion, the most reasonable approach would be the evaluation to be performed in intermediate stages incorporated in optimization step. For example, when a crucial green(er) approach is applied, analytical performance could be evaluated in terms of partial validation studying certain parameters, before full validation would be performed. So that if changes were necessary, no time, energy and consumables would be wasted.

Moreover, the use of these tools aims to showcase the strong but also the weak points of the methods. Thus, any weakness should be known in advance in order to improve the method by eliminating the drawbacks and optimizing overall performance.

What is “White Analytical Chemistry” How feasible is it to integrate “White Analytical Chemistry” (green + blue + red metrics) into routine chromatographic workflows?

White Analytical Chemistry¹² is a holistic approach complementary to Green Analytical Chemistry, based on three colors model: Green, Blue and Red. According to this concept, in addition to the green attributes, practicality (the blue part) and analytical performance of the method (the red part) should be also taken into account.

I believe it is feasible to integrate “White Analytical Chemistry” into routine chromatographic workflows. In research and development labs, integrating “White Analytical Chemistry” evaluation is more than mandatory. For example, in our laboratory we have already implemented this strategy in all methods we develop. We have chosen the most practical metric tools. According to my experience and personal opinion, based on familiarity and gained in practice, we have concluded that the combination of a green tool e.g. AGREE/AGREEPrep or MoGAPI/ComplexMoGAPI for greenness evaluation, BAGI¹³ for blue part (practicality and applicability) and RAPI¹⁴ for red part (analytical performance) is effective to evaluate the overall performance of the method and also provides the data to support comparison between methods.

This approach could be also the case for routine chromatographic workflows. Though in some cases (e.g. for accredited laboratories, or state laboratories) the flexibility to make changes after the WAC evaluation is limited. But at least the analytical chemists should be aware of the characteristics of the routine method they apply.

Would you support making metric evaluation mandatory for publication or regulatory submission of chromatographic methods?

Eventually yes, I would definitely support this approach to be mandatory, for publication or regulatory submission of chromatographic methods, because metric evaluation strengthens the conclusions. Any claims are supported by transparent data and the results are indisputable.

Especially for chromatographic methods metric tools may provide a more structured framework in order to choose the best conditions in terms of sustainability and circularity.

However, due to proliferation of the available metric tools, harmonization should precede, to ensure the quality of the measurements and enhance the comparability and transferability of analytical methods.

What would an ideal harmonized framework look like?

As I mentioned before, there are many metric tools with slight modifications. The authors or the analytical scientists may choose what is more favorable to show the superiority of their method. This is subjective. On the other hand, reviewers may suggest the application of specific tools according to their knowledge. This may be biased. Conflicts of interest may also exist. Therefore, in my opinion accreditation of the already proposed metrics would be useful, so that the analytical scientist can choose among reliable tools and the results can be comparable.

Guidelines for harmonization could be set by organizations, such as ISO, Eurachem, IUPAC or Scientific Association Committees (RSC, ACS, EuChemS) from relevant divisions e.g. the Division of Analytical Chemistry. Task forces or working groups can evaluate the existing metric tools and provide a list of accepted or suggested ones for each case. Since we cannot have one universal metric tool that fits all applications, at least we can have a list of recommended or even better approved, so that we can choose which is suitable for routine analysis, for trace analysis, for food samples, for environmental monitoring, for bioanalysis, omics, regulatory, industry etc.

Any final thoughts on the future of sustainability in separation science?

Though in ultrahigh-performance liquid chromatography instruments (UHPLC) instruments the solvent consumption has significantly decreased, the overall solvent quantities remain a decisive figure due to the inevitable sample preparation steps. Sustainable approaches might involve the use of greener bio-based solvents, which, however, are sold at much higher prices than the regular ones. This increases the final cost and renders the method rather expensive and not feasible, especially in routine analysis.

So, sustainability should additionally be affordable otherwise it is not realistic.

But, as I have said in the past, as Analytical chemists we have all the solutions, and even if we don’t, we have the standards to prepare fresh ones! I am confident that analytical scientists can support or even guarantee a sustainable future in chromatographic separations. Metric tools may help to this direction.

References

1. Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice, Oxford University Press, 1998.
2. Keith, L. H.; Gron, L. U.; Young, J. L. Green Analytical Methodologies. Chem Rev 2007,107 (6), 2695–2708. DOI: 10.1021/cr068359e
3. Gałuszka, A.; Migaszewski, Z. M.; Konieczka, P.; J. Namieśnik. Analytical Eco-Scale for Assessing the Greenness of Analytical Procedures. Trends Anal Chem 2012, 37, 61–72. DOI: 10.1016/j.trac.2012.03.013
4. Płotka-Wasylka, J. A New Tool for the Evaluation of the Analytical Procedure: Green Analytical Procedure Index. Talanta 2018, 181, 204–209. DOI:10.1016/j.talanta.2018.01.013
5. Pena-Pereira, F.; Wojnowski, W.; Tobiszewski, M. AGREE—Analytical GREEnness Metric Approach and Software. Anal Chem 2020, 92 (14), 10076–10082. DOI: 10.1021/acs.analchem.0c01887
6. Wojnowski, W.; Tobiszewski, M.; Pena-Pereira, F.; Psillakis, E. AGREEprep – Analytical Greenness Metric for Sample Preparation. Trends Anal Chem 2022, 149, 116553. DOI:10.1016/j.trac.2022.116553.
7. Płotka-Wasylka, J.; Wojnowski, W. Complementary Green Analytical Procedure Index (ComplexGAPI) and Software. Green Chem 2021, 23, 8657. DOI: 10.1039/d1gc02318g rsc.li/greenchem
8. Mansour, F.R.; Płotka-Wasylka, J.; Locatelli, M. Modified GAPI (MoGAPI) Tool and Software for the Assessment of Method Greenness: Case Studies and Applications. Analytica 2024, 5(3), 451–457. DOI: 10.3390/analytica5030030
9. Mansour, F. R.; Omer, K. M.; Płotka-Wasylka, J. A Total Scoring System and Software for Complex Modified GAPI (ComplexMoGAPI) Application in the Assessment of Method Greenness. Green Anal Chem 2024, 10, 100126. DOI: 10.1016/j.greeac.2024.100126
10. Nowak, P. M.; Wietecha-Posłuszny, R.; Pawliszyn, J. White Analytical Chemistry: An Approach to Reconcile the Principles of Green Analytical Chemistry and Functionality. Trends Anal Chem 2021, 138, 116223. DOI: 10.1016/j.trac.2021.116223
11. Samanidou, V. Metric Tools in Analytical Chemistry: From Proliferation to Harmonization, Green Anal Chem 2026, 16, 100326. DOI: 10.1016/j.greeac.2026.100326
12. Gałuszka, A.; Migaszewski, Z.; Namieśnik, J. The 12 Principles of Green Analytical Chemistry and the SIGNIFICANCE Mnemonic of Green Analytical Practices. Trends Anal Chem 2013, 50, 78–84. DOI: 10.1016/j.trac.2013.04.010
13. Manousi, N.; Wojnowski, W.; Płotka-Wasylka, J.; Samanidou, V. Blue Applicability Grade Index (BAGI) and Software: A New Tool for the Evaluation of Method Practicality. Green Chem 2023, 25, 7598. DOI: 10.1039/d3gc02347h rsc.li/greenchem
14. Nowak, P.M.; Wojnowski, W.; Manousi, N.; Samanidou, V.; Płotka-Wasylka, J. Red Analytical Performance Index (RAPI) and Software: The Missing Tool for Assessing Methods in Terms of Analytical Performance. Green Chem 2025, 27, 5546. DOI: 10.1039/D4GC05298F