Designing of molecularly imprinted polymer with carboxylic acid functionality for chiral separation of (±)-3,4-methylenedioxymethamphetamine

In this work, we discuss the development of a long-lasting enantioselective material for the effective enantio-recognition of S-3,4-methylenedioxymethamphetamine (S-MDMA) and chiral separation of the (±)-MDMA racemate using a crosslinked poly(acrylic acid-4-vinylpyridine) copolymer. The first step was the synthesis and characterization of an acryloyl-S-MDMA amide. After that, the free radical initiator azobisisobutyronitrile was used to copolymerize the synthesized chiral amide with 4-vinylpyridine and divinylbenzene. The incorporated S-MDMA species were extracted from the polymeric particles by heating them with sodium hydroxide, followed by rinsing with hydrochloric acid. This developed the molecularly imprinted S-MDMA particles, which were visualized with a scanning electron microscope and Fourier transform infrared spectroscopy. The selectivity parameters indicated a higher affinity of the fabricated S-MDMA imprinted particles toward S-MDMA, around 10-fold higher than that related to R-MDMA. Results from Langmuir adsorption experiments at pH 6 demonstrated a maximal capacity of 142 mg g⁻¹. In addition, the values of enantiomeric excess were found to be 94.5% and 79.4% for R- and S-MDMA in the loading and eluant solutions, respectively, after optical separation was done using the column technique. © 2023 Society of Industrial Chemistry.