ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Determination of four trace preservatives in street food by ionic liquid-based dispersive liquid-liquid micro-extraction

Peng Yang, Haixia Ren, Hongdeng Qiu, Xia Liu, and Shengxiang Jiang

Key Laboratory of Chemistry of North-Western Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 China

E-mail: sxjiang@lzb.ac.cn

Abstract: A rapid and simple ionic liquid-based dispersive liquid-liquid micro-extraction (DLLME) method has been developed to pre-concentrate four paraben preservatives (methylparaben, ethylparaben, propylparaben, and butylparaben) from street food (pancakes). Several potentially influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength, and the volume of the ionic liquid and disperser solvent were investigated. The optimum experimental conditions for the proposed micro-extraction process were: 0.1 mL of 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈MIM][PF₆]) as an extraction solvent, 0.1 mL of acetonitrile as a disperser solvent, 5 min extraction time, and sample ionic strength of 30 % sodium chloride in water sample at pH 6.0. The LODs and LOQs were in the range of 1.0–1.5 ng g⁻¹ and 3.5–4.5 ng g⁻¹, respectively. Spiking recoveries were in the range of 60.1–79.5 % and the associated RSDs were all in the range of 1.8–7.0 %. The results show that DLLME is a suitable method for the determination of parabens in pancake samples and ionic liquid is a good extractant in this process.

Keywords: parabens – ionic liquid – dispersive liquid-liquid micro-extraction – high performance liquid chromatography

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-011-0071-9

Chemical Papers 65 (6) 747–753 (2011)