Development of magnetic micro-solid phase extraction for analysis of phthalate esters in packaged food

A novel, simple and low cost magnetic multi-walled carbon nanotubes-poly (vinyl alcohol) cryogel-micro-solid phase extraction (magnetic-MWCNTs-PVA cryogel-mu-SPE) sorbent was synthesized by incorporating magnetic particles and MWCNTs into a PVA cryogel. The magnetic-MWCNTs-PVA cryogel-mu-SPE sorbent developed, with a large surface area and macro-porous structure, provided good sorbent-to-sorbent reproducibility (%RSD < 8) and each sorbent could be used up to 30 times (%RSD < 6). This sorbent was applied for the extraction of dibutyl phthalate (DBP) and di-2-(ethylhexyl) phthalate (DEHP) in packaged food prior to analysis by gas chromatograph coupled with flame ionisation detector (GC-FID). The concentration of DBP and DEHP in hot-water samples from plastic bags were found in the range 0.04-0.15 mu g mL(-1) and 0.03-0.20 mu g mL(-1), respectively, but only DEHP was found in clear chicken soup samples in the range 0.02-0.07 mu g mL(-1). (C) 2014 Elsevier Ltd. All rights reserved.