Multivariate optimization of an extraction procedure based on magnetic molecular imprinted polymer for the determination of polycyclic aromatic hydrocarbons in sea water

Abstract

The present work deals with the optimization of a magnetic solid phase extraction of polycyclic aromatic hydrocarbons (PAHs) from sea water, based on molecular imprinted microparticles, for subsequent GC–MS analysis. The extraction efficiency of the magnetic molecular imprinted polymer (MIP) was compared with that of the corresponding non-imprinted polymer; only small differences in the recovery of the extraction procedure were shown, but higher repeatability was observed using MIP. An experimental design (Plackett-Burman) allowed a fast optimization identifying the only significant factor influencing the extraction recovery, namely the ratio between the amount of microparticles and the sample volume. Two optimal ratios, based on the PAHs molecular weight, were selected for 20 mL of sea water samples: 5 mg or 20 mg of microparticles for compounds ranging from 128 to 228 and from 252 to 278 Da, respectively. The recoveries ranges were 76–104% for the low molecular weight PAHs and 95–101% for the high molecular weight PAHs. The analytical method showed satisfactory figures of merit, with detection limits ranging from 30 to 375 ng L−1 and relative standard deviations on replicate extractions from 3.7 to 12.2%. The developed method, which is fast, easy and requires very small volumes of organic solvent, was applied for the determination of PAHs in selected sea water samples.