Molecularly imprinted polymers-based microextraction techniques

Sample preparation is still considered the bottle-neck of the whole analytical process. Nowadays, several sample preparation techniques are available, however all of them suffer of lack of the selectivity. At this regard, molecularly imprinted polymers (MIPs) are considered excellent materials able to perform selective extractions. MIPs are tailor-made stable polymers with molecular recognition abilities, provided by the presence of a template during their synthesis. Thus, MIPs are excellent materials to provide selectivity to sample preparation, being its use in solid-phase extraction, so-called “molecularly imprinted solid-phase extraction” (MISPE), well-stablished nowadays. Recently, new objectives in sample preparation have been set, including to use smaller initial sample sizes; to facilitate automation; and, to minimize the amount of glassware and organic solvents needed. MIP incorporation to other microextaction techniques, such as micro solid-phase extraction, solid-phase microextraction, stir bar sorptive extraction or liquid-phase microextraction offers a new strategy in order to fulfil current sample preparation requirements. Accordingly, the different recent approaches towards the development of MIP-based microextraction techniques are described in the present review. The advantages and drawbacks of each methodology as well as the future expected trends are discussed.