Determination of phthalates in food packing materials by electrokinetic chromatography with polymeric pseudostationary phase

Polymeric pseudostationary phase (PSP), formed by random copolymer poly (stearyl methacrylate-co-methacrylic acid) (P(SMA-co-MAA)), was used in electrokinetic chromatography (EKC) to separate 15 kinds of phthalates (PAEs). The organic solvent modifier is a key factor for the separation of PAEs. Without organic solvents, only four kinds of PAEs with smaller molecular weight could be separated in the running buffer containing 1% P(SMA-co-MM). The other eleven kinds of PAEs with larger molecular weight could be separated within 25 min by adding 40% (v/v) methanol and 2% (v/v) 1-butanol in the running buffer. The linear ranges of 15 kinds of PAEs were between 2 and 200 mg/L, and the limit of detection based on the ratio of signal to noise of 3 were between 1 and 3 mg/L. The method was applied to determination of PAEs in 6 kinds of food packing materials. The recoveries were between 81% and 118% with the RSD less than 4%. (C) 2015 Elsevier Ltd. All rights reserved.