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Chromatography and Sustainability: A Path Forward

Scientist in white lab coat holding a green earth to represent lab sustainability.
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Chromatography is an analytical technique used to separate and detect the chemical components in a sample. It is an incredibly versatile technique that can be used in essentially any scientific discipline, such as food analysis, environmental analysis, forensic and pharmaceutical analysis.


Chromatography has become extremely popular due to its separation capability, high sensitivity and ease of automation. These three characteristics collectively make chromatography well-suited for validated methods and routine analytical applications.


Despite its utility, traditional chromatographic techniques raise significant environmental concerns. Many chromatography techniques contribute to environmental pollution and resource depletion, which is increasingly at odds with the growing emphasis on sustainability in scientific research and industry. Addressing these issues is critical to making chromatography not only a powerful analytical tool but a more eco-friendly and responsible choice for future applications.

Understanding the environmental impact of chromatography

As chromatography is a routine method across multiple disciplines, hundreds and thousands of analyses are performed every day, meaning many instruments are running 24/7 – thus demanding a high amount of energy and electricity. Electricity consumption also depends on the detection method used for the analysis. Whether it's an ultraviolet (UV) detector or a mass spectrometer, there is a very big difference in electricity consumption – with mass spectrometry (MS) requiring much more energy.


In liquid chromatography (LC), a significant volume of solvent is used daily, with acetonitrile remaining the most common organic mobile phase component. However, acetonitrile is both toxic and environmentally harmful, leading to substantial volumes of toxic waste.


In contrast, gas chromatography (GC) does not use a liquid mobile phase; instead, it relies on gases, with helium being the most commonly used. Helium, however, is a finite resource on Earth and is produced only through the radioactive decay of certain heavy elements from the actinides. Once released into the atmosphere, it dissipates rapidly due to its volatility, highlighting its scarcity.

“Greener” solvents and methods in chromatography

Understanding the properties a solvent needs to have to make it “greener” is the first step to making chromatography more sustainable. When looking at the 12 Principles of Green Chemistry, there are 2 main options concerning solvents. One option is that you use a solvent from a bio-based resource and the other is that you use a solvent that is less hazardous or is a safer alternative to something that is used now.


There is a broad range of bio-based solvents on offer already, such as ethanol and isopropanol, which can be used for high-performance liquid chromatography (HPLC). Other solvents, such as propylene carbonate, dimethyl carbonate or even CyreneTM (dihydrolevoglucosenone) – a solvent based on cellulose waste – have also been considered. However, these bio-based solvents do have some drawbacks, such as having a very high back pressure, limited miscibility with water or having a high UV cutoff.


Currently, none of these bio-based solvents can be traded one-for-one with the current solvents used. Despite this, there are some solutions to the application of bio-based solvents, such as achieving a lower viscosity by increasing the column temperature (if the column allows to do so). Another solution could be using a monolithic material in the column, which has a significantly lower backpressure compared to the standardly used particle-packed columns – meaning the implementation of ethanol or isopropanol could be significantly easier. The issue with UV cutoff can be addressed by choosing a different detector. And lastly, a common workaround for limited miscibility with water is the addition of some ethanol (of course biobased) to the mobile phase.


Method optimization can also increase the sustainability of chromatography. One aspect that has a significant impact is the column’s internal diameter, or column size in general. Making a column shorter and with a smaller diameter significantly drops solvent consumption. For example, globally the most used standard column is still 25 cm x 4.6 mm. If we move to a column measuring 10 cm x 2.1 mm, we already save almost 90% of solvent usage. The loss in separation efficiency by reducing the column length can be compensated by using more efficient, smaller fully porous particles or by more efficient superficially porous particles (which additionally can be smaller to further increase efficiency) in the column. Of course, this would increase the backpressure and a different type of instrumentation would be needed – but it is easily possible with current UHPLC (ultra-high-performance liquid chromatography) instruments.

Other ways of making chromatography greener

Sample preparation is still considered as one of the steps in the analytical workflow with the highest consumption of reagents and solvents. Resultingly, miniaturization of sample preparation would significantly contribute to making chromatography greener in terms of reducing the large volumes of solvents for extraction that have been used in the past.


One example of such miniaturization is pesticide analysis: in the methods from more than 20 years ago, large amounts of hazardous solvents have been used for liquid-liquid extraction, gel permeation chromatography and column chromatography. With the QuEChERS method, this has been reduced to only 10 mL of acetonitrile – showing a tremendous improvement for sustainability.1 But even from there, you can further improve the sample prep. For example, solid phase microextraction is a completely solvent-free analytical technique that makes chromatography even greener, and it can be employed for greener pesticide analysis.2


My Green Lab – a non-profit organization aiming to improve the sustainability of scientific research – already issues ACTTM (accountability, consistency and transparency) labels to instruments, which includes assessing their energy consumption and allows for comparison between instruments. When a laboratory is thinking about investing in a new instrument, electricity consumption should be seriously considered. LC-MS usage should also be limited and only used where necessary, for example, where some compounds cannot be separated chromatographically and must be separated by mass. Non-targeted separations mainly require LC-MS because of significantly higher sensitivity and simultaneous compound identification. However, if you have compounds that are easily separated and are UV detectable, then LC-UV should be used because it has a lower electricity consumption.


More broadly, the packaging of solvents (e.g., returnable containers instead of one-way glass bottles significantly reduce the carbon footprint), how samples are stored (i.e., in a fridge or freezer) and other laboratory operating procedures all play a role in sustainability and need to be developed.


It is important to develop “green thinking” in general and make sure that every step we take, no matter where it is, is a step towards being more sustainable.

Developing a green future for chromatography

Miniaturization is always a question. How much can chromatography be miniaturized? Can we move to nanotechnology? It would be an incredible achievement if a droplet of solvent would be sufficient for these day-long, large number of analyses. But we should also aim to make future methods as green as possible by applying what is discussed above, to really change what we do at the moment.


Although there are a lot of examples and advice on how to become a greener lab, developing a mindset for reducing environmental impact should be at the heart of chromatography, and science as a whole. Whether it's sample collection, sample preservation, storage or the analytical run itself – keeping in mind how to act most sustainably is very important and a lot would be gained from this. 


  1. Anastassiades M, Lehotay S, et al., Fast and easy multiresidue method employing acetonitrile extraction/partitioning and “dispersive solid-phase extraction” for the determination of pesticide residues in produce. J. AOAC Int. 86/2. 2003. 412-431. doi: 10.1093/jaoac/86.2.412
  2. Souza-Silva ÉA, Lopez-Avila V, Pawliszyn J., Fast and robust direct immersion solid phase microextraction coupled with gas chromatography–time-of-flight mass spectrometry method employing a matrix compatible fiber for determination of triazole fungicides in fruits. J. Chromatogr. A. 1313. 2013. 139-146. doi: 10.1016/j.chroma.2013.07.071