Assessment of the greenness of molecularly imprinted polymers used in sample preparation

• AGREEMIP tool is used for assessing the greenness of MIP synthesis procedures • Scores obtained clearly show that there is an abuse of the use of green-related terms • Guidelines for greening MIPs used in sample preparation are provided • Reduction of the amounts of toxic solvents during MIP synthesis is one of the key aspects It is now widely accepted that the incorporation of molecularly imprinted polymers (MIPs) into sample preparation techniques has enabled unprecedented selectivity performance of analytical methods for the determination of a wide range of analytes in biological, food and environmental samples. However, according to the Principles of Green Chemistry and the subsequent Principles of Green Sample Preparation, it is clear that MIPs are far from being considered green materials, both due to the common harmful reagents and the experimental conditions used for their synthesis. Accordingly, new greener routes for MIP synthesis have been proposed in recent years. However, although the titles of some of the published papers include terms such as 'green MIP' or 'sustainable MIP', such improved properties have only been assessed intuitively and it is therefore unclear whether such claimed green or sustainable MIPs are actually so. Therefore, in the present review, published papers using apparently green MIPs in sample preparation were evaluated using the recently developed metric tool AGREEMIP. Such a tool is based on the assessment of 12 criteria related to the greenness of the different reagents used, energy requirements and other aspects of MIP synthesis procedures. The final values of performed AGREEMIP assessment ranged from 0.28 to 0.80. The scores obtained after the AGREEMIP assessment clearly show that, although slight improvements have been achieved in terms of greenness, there is an abuse of the use of green-related terms and further development is needed. In this context, some guidelines for greening MIPs are provided.