Paul Vanden Branden, Director at SciMed, discusses how laboratories can update experimental methods and solvent selection to be more sustainable without harming results.

Research labs are complicated environments and it is not always clear what can be done to improve sustainability.

To date, most of the discussion around sustainability has focused on the energy efficiency of instruments and equipment, such as fume hoods and cryogenic freezers.

While this is important, it means that things like chemical and solvent selection are overlooked. But climate change is arguably the most pressing issue of our time, with many scientists warning that, if significant progress is not made towards becoming a more sustainable society, damage to the planet will become irreversible.

The UK Government has committed in legislation to achieve net-zero carbon emissions by 2050, but this is unlikely to happen unless there are substantial changes across industrial sectors such as the lab industry.

University College London’s sustainability report for 2021 reported that roughly half of the university’s emissions came from its laboratories. The findings of this report, and others like it, indicate that laboratories must do more. Ultimately, this means the lab industry will significantly impact the likelihood of meeting the ‘Net zero by 2050‘ goal. Therefore, laboratories must address problems such energy consumption as well as chemical and solvent selection.

Switching to green solvents

Organic solvents, such as hexane, are commonly used in various chemical processes, such as separations and extractions, but are quite environmentally harmful. Therefore, a key goal for the lab industry is to reduce their use in favour of green solvent alternatives.

Hexane is widely used for extracting oil contaminants from water and soil for analysis and for extracting edible oils from seeds and vegetables because of its efficiency in these experiments, which could not traditionally be matched by alternatives. However, supercritical CO2 systems now allow comparable results to be achieved without using such a harmful chemical.

For example, supercritical liquid CO2 is non-flammable, non-toxic, not environmentally harmful, easy to prepare and does not contribute to global warming because any process CO2 is recycled back into the system. Supercritical fluid extraction (SFE) is an area of growing interest and CO2 is the most common supercritical fluid used in SFE procedures as a replacement for traditional hexane use.

SFE is performed by pumping supercritical CO2 through a fixed bed of substrate where the CO2 flows through the substrate and dissolves soluble components until they are depleted. The loaded solvent is then passed through a separator where the soluble components are precipitated by adjusting the temperature and pressure before the CO2 is condensed and recirculated.

By controlling the density of supercritical CO2 fluids, they can replicate the performance of various organic solvents whose polarities range from n-pentane, at the lowest density, to pyridine, at the highest. This feature allows selective extraction, purification and fractionation procedures to be performed.

This just one of many examples of ways the lab industry can improve chemical and solvent selection in experimentation to improve sustainability without negatively impacting results.

The Sustainable Laboratory returns to Lab Innovations in November 2023, hosted by Andy Evans, director of Green Light Laboratories. SciMed is an exhibitor at the event and member of the show’s advisory board