期刊
ANALYTICA CHIMICA ACTA
卷 754, 期 -, 页码 61-66出版社
ELSEVIER
DOI: 10.1016/j.aca.2012.10.010
关键词
pH controlled DLLME; Ochratoxin A; HPLC-FLD; Cereal; Sample preparation
A new sample preparation procedure, termed pH-controlled dispersive liquid-liquid microextraction (pH-DLLME), has been developed for the analysis of ionisable compounds in highly complex matrices. This DLLME mode, intended to improve the selectivity and to expand the application range of DLLME, is based on two successive DLLMEs conducted at opposite pH values. pH-DLLME was applied to determination of ochratoxin A (OTA) in cereals. The hydrophobic matrix interferences in the raw methanol extract (disperser. 1 mL) were removed by a first DLLME (I DLLME) performed at pH 8 to reduce the solubility of OTA in the extractant (CCl4, 400 mu L). The pH of the aqueous phase was then adjusted to 2, and the analyte was extracted and concentrated by a second DLLME (extractant, 150 mu L C2H4Br2). The main factors influencing the efficiency of pH-DLLME including type and volume of I DLLME extractant, as well as the parameters affecting the OTA extraction by II DLLME, were studied in detail. Under optimum conditions, the method has detection and quantification limits of 0.019 and 0.062 mu g kg(-1), respectively, with OTA recoveries in the range of 81.2-90.1% (n = 3). The accuracy of the analytical procedure, evaluated with a reference material (cereal naturally contaminated with OTA), is acceptable (accuracy of 85.6% +/- 1.7, n = 5). The applicability of pH-DLLME to the selective extraction of other ionisable compounds, such as acidic and basic pharmaceutical products was also demonstrated. The additional advantages of pH-DLLME are a higher selectivity and the extension of this microextraction technique to highly complex matrices. (C) 2012 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据