Study of selectivity of molecularly imprinted polymers prepared under different conditions.

Molecularly imprinted polymers were prepared and tested in different ways. 1-Methyl-2-piperidinoethylester of 4-decyloxyphenylcarbamic acid was used as the template for imprints formation. Acrylamide, 4-vinylpyridine, and methacrylic acid as monomers and methanol and acetonitrile as a porogene were used. Non-imprinted polymers were prepared for each imprinted polymer by the same procedure. Polymers were employed as sorbents for solid-phase extraction. In this work the influence of polymerization mixture composition on polymer properties, such as capacity and selectivity, was investigated. The influence of alkoxy-chain length and the position on benzene ring on the selectivity of polymers was also investigated.

Selective extraction of derivates of p-hydroxy-benzoic acid from plant material by using a molecularly imprinted polymer.

Selective SPE of derivates of p-hydroxybenzoic acid (pHBA) from plant extract of Melissa officinalis is presented using a molecularly imprinted polymer (MIP) made with protocatechuic acid (PA) as template molecule. MIP was prepared with acrylamide as functional monomer, ethylene glycol dimethacrylate as crosslinking monomer and ACN as porogen. MIP was evaluated towards six phenolic acids: PA, gallic acid, pHBA, vanillic acid (VA), gentisic acid (GeA) and syringic acid (SyrA), and then steps of molecularly imprinted SPE (MISPE) procedure were optimized. The best specific binding capacity of MIP was obtained for PA in ACN (34.7 microg/g of MIP). Other tested acids were also bound on MIP if they were dissolved in this solvent. ACN was chosen as solvent for sample application. M. officinalis was extracted into methanol/water (4:1, v/v), the extract was then evaporated to dryness and dissolved in ACN before application on MIP. Water and ACN were used as washing solvents and elution of benzoic acids was performed by means of a mixture methanol/acetic acid (9:1, v/v). pHBA, GA, PA and VA were extracted with recoveries of 56.3-82.1% using this MISPE method. GeA was not determined in plant extract.