Affinity chromatography - a natural tool for green separations and analysis: a perspective and mini-review

Analytical methods using liquid chromatography, such as reversed-phase or normal-phase separations, are often hindered in their extent of environmental friendliness by their use of organic solvents in the mobile phase. Affinity chromatography is an alternative approach for chemical separations that frequently uses biologically-based stationary phases and aqueous mobile phases, thus providing a better fit with the goals of green analytical chemistry. In this perspective and mini-review, various greenness tests (i.e., NEMI, AGP, EcoScale and Analytical EcoScale) and related tools that have been developed for green analytical chemistry (i.e., AGREE, MoGAPI, Complex MoGAPI, BAGI, RGBfast) will be used to evaluate five recently-reported affinity chromatographic methods that represent various applications for this separation and analysis technique. The assessment results for each method will be examined in terms of the observed strengths and limitations with regards to its greenness and environmental impact. Although the emphasis in this report and cited examples is analytical applications involving biological agents, extension of the same assessment approaches to other types and formats of affinity chromatography will also be considered. The results should be useful in determining the potential of affinity chromatography as a green analytical method and in identifying ways in which this method may be further improved and employed in future work for this purpose.