Khajeh Mostafa, Yamini Yadollah, Hassan Jalal
Department of Chemistry, Tarbiat Modarres University, Tehran, Iran.
Talanta. 2006 Jul 15;69(5):1088-94. doi: 10.1016/j.talanta.2005.12.020. Epub 2006 Jan 18.
In the present work, a rapid method for the extraction and determination of chlorobenzenes (CBs) such as monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4-trichlorobenzene in water samples using the headspace solvent microextraction (HSME) and gas chromatography/electron capture detector (ECD) has been described. A microdrop of the dodecane containing monobromobenzene (internal standard) was used as extracting solvent in this investigation. The analytes were extracted by suspending a 2.5 microl extraction drop directly from the tip of a microsyringe fixed above an extraction vial with a septum in a way that the needle passed through the septum and the needle tip appeared above the surface of the solution. After the extraction was finished, the drop was retracted back into the needle and injected directly into a GC column. Optimization of experimental conditions such as nature of the extracting solvent, microdrop and sample temperatures, stirring rate, microdrop and sample volumes, the ionic strength and extraction time were investigated. The optimized conditions were as follows: dodecane as the extracting solvent, the extraction temperature, 45 degrees C; the sodium chloride concentration, 2M; the extraction time, 5.0 min; the stirring rate, 500 rpm; the drop volume, 2.5 microl; the sample volume, 7 ml; the microsyringe needle temperature, 0.0 degrees C. The limit of detection (LOD) ranged from 0.1 microg/l (for 1,3-dichlorobenzene) to 3.0 microg/l (for 1,4-dichlorobenzene) and linear range of 0.5-3.0 microg/l for 1,2-dichlorobenzene, 1,3-dichlorobenzene and from 5.0 to 20.0 microg/l for monochlorobenzene and from 5.0 to 30 microg/l for 1,4-dichlorobenzene. The relative standard deviations (R.S.D.) for most of CBs at the 5 microg/l level were below 10%. The optimized procedure was successfully applied to the extraction and determination of CBs in different water samples.
在本研究中，描述了一种采用顶空溶剂微萃取（HSME）和气相色谱/电子捕获检测器（ECD）快速萃取和测定水样中氯苯（CBs）的方法，这些氯苯包括一氯苯、1,2 - 二氯苯、1,3 - 二氯苯、1,4 - 二氯苯、1,2,3 - 三氯苯和1,2,4 - 三氯苯。本研究中使用含一溴苯（内标）的十二烷微滴作为萃取溶剂。通过将2.5微升萃取液滴直接从固定在带有隔膜的萃取瓶上方的微量注射器尖端悬垂下来进行萃取，使针头穿过隔膜且针尖出现在溶液表面上方。萃取完成后，将液滴缩回针头并直接注入气相色谱柱。研究了萃取溶剂的性质、微滴和样品温度、搅拌速率、微滴和样品体积、离子强度以及萃取时间等实验条件的优化。优化条件如下：十二烷作为萃取溶剂，萃取温度45℃；氯化钠浓度2M；萃取时间5.0分钟；搅拌速率500转/分钟；液滴体积2.5微升；样品体积7毫升；微量注射器针头温度0.0℃。检测限（LOD）范围为0.1微克/升（对于1,3 - 二氯苯）至3.0微克/升（对于1,4 - 二氯苯），1,2 - 二氯苯和1,3 - 二氯苯的线性范围为0.5 - 3.0微克/升，一氯苯为5.0至20.0微克/升，1,4 - 二氯苯为5.0至30微克/升。大多数氯苯在5微克/升水平的相对标准偏差（R.S.D.）低于10%。该优化方法成功应用于不同水样中氯苯的萃取和测定。
