Greenness assessment of exemplary US EPA and DIN standard analytical methods using the AGREEprep model

Abstract

Sustainable development principles have become a common consensus and a challenge to humanity, shifting the societal focus towards greener alternatives. The chemical sector, in particular analytical chemistry tends to attain a leading role in this initiative as it strives to incorporate green chemistry principles when designing and proposing new chemical solutions. Sample preparation is considered a critical stage in an analytical procedure regarding waste generation and resource consumption. The main goal of this work was to evaluate the sample preparation greenness of selected analytical standard procedures. Accordingly, three reference methods from the United States Environmental Protection Agency (EPA methods 523, 528, and 610) and one method from the German Institute for Standardization (DIN 38047–37), which use classical solid-phase and liquid-liquid extraction as the core of their sample preparation procedures, were evaluated via AGREEprep, a green metric tool designed specifically for evaluation of sample preparation greenness. In addition, the methods were compared with twenty novel analytical alternatives reported in the literature, including a variety of solid-phase and liquid-phase microextraction techniques. In all cases, the miniaturized sample preparation strategies showed superior greenness over the standard methods, while providing similar or better analytical performance. The main evidenced shortcomings of the standard methods were the large sample volume required for the extraction and the use of large volumes of organic solvents. The overall results confirmed that the shift toward green approaches for sample preparation integrating sustainable extraction protocols and greener methodologies has the potential to improve the environmental performance of the analytical method.