Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran.
J Sep Sci. 2012 Mar;35(5-6):742-9. doi: 10.1002/jssc.201100853. Epub 2012 Jan 24.
A simple and economic method for the analysis of phthalate esters, dimethyl phthalate, diethyl phthalate, di-iso-butyl phthalate, di-n-butyl phthalate, and di-2-ethylhexyl phthalate in cow milk samples by means of gas chromatography-flame ionization detection and gas chromatography-mass spectrometry has been developed. In this work, NaCl and ACN were added to 5 mL of the milk sample as the salting out agent and extraction solvent, respectively. After manual shaking, the mixture was centrifuged. In the presence of NaCl, a two-phase system was formed: upper phase - acetonitrile containing phthalate esters -and lower phase - aqueous phase containing soluble compounds and the precipitated proteins. After the extraction of phthalate esters from milk, a portion of supernatant phase (acetonitrile) was removed, mixed with 1,2-dibromoethane at microliter level and injected by syringe into NaCl solution. After the extraction of the selected phthalate esters into 1,2-dibromoethane, phase separation was performed by centrifugation and the enriched analytes in the sedimented phase were determined by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. Under the optimum extraction conditions, low limits of detection and quantification between 1.5-3 and 2.5-11 ng/mL, respectively was observed. Enrichment factors were in the range of 397-499. The relative standard deviations for the extraction of 100 ng/mL of each phthalate ester were in the range of 3-4% (n = 6). Finally, some milk samples were successfully analyzed using the proposed method and two analytes, di-n-butyl phthalate and di-2-ethylhyxel phthalate, were determined in them in nanogram per milliliter level.
已经开发出一种简单经济的方法，用于通过气相色谱-火焰离子化检测和气相色谱-质谱法分析牛奶样品中的邻苯二甲酸酯、邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二异丁酯、邻苯二甲酸二正丁酯和邻苯二甲酸二（2-乙基己基）酯。在这项工作中，将 NaCl 和 ACN 添加到 5 mL 牛奶样品中，分别作为盐析剂和提取溶剂。手动摇晃后，将混合物离心。在 NaCl 的存在下，形成两相体系：上层-含有邻苯二甲酸酯的乙腈相-和下层-含有可溶性化合物和沉淀蛋白质的水相。从牛奶中提取邻苯二甲酸酯后，去除一部分上清液（乙腈），与 1,2-二溴乙烷在微升水平混合，并用注射器注入 NaCl 溶液。在选择的邻苯二甲酸酯萃取到 1,2-二溴乙烷后，通过离心进行相分离，并通过气相色谱-火焰离子化检测和气相色谱-质谱法测定沉淀相中富集的分析物。在最佳提取条件下，观察到检测限和定量限分别为 1.5-3 和 2.5-11 ng/mL。富集因子在 397-499 范围内。以 100 ng/mL 的每种邻苯二甲酸酯的提取的相对标准偏差在 3-4%（n = 6）范围内。最后，使用所提出的方法成功分析了一些牛奶样品，并在其中测定了两种分析物，即邻苯二甲酸二正丁酯和邻苯二甲酸二（2-乙基己基）酯，其浓度均为纳克/毫升级。
