2-hydroxyethyl methacrylate HEMA incorporation

A means to avoid such tedious optimization can be envisaged by employing stoichiometric monomers to develop strong interactions with the template as mentioned above. The other way is to incorporate hydrophilic comonomers (2-hydroxyethyl methacrylate (HEMA), acrylamide) or cross-linkers (pentaerythri-toltriacrylate, methylene bisacrylamide) in the polymer. This results in an increase of the hydrophilicity of the polymer. Indeed, the use of HEMA for a MIP directed towards the anesthetic bupivacaine resulted in high imprinting factors due to reduced non-specific hydrophobic adsorption in aqueous buffer. This was not the case when HEMA was omitted from the polymerization mixture [27]. These conditions were exploited for the direct and selective extraction of bupivacaine from blood plasma samples. 

Hydroxyl functional groups may be incorporated into latex particles by using monomers such as 2-hydroxyethyl methacrylate (HEMA) or hydroxypropyl methacrylate (HPMA). Both monomers are liquid, have approximately the same boiling point (95 and 96 °C at 10 mm Hg, respectively), and are moderately soluble in water [9]. 

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