微波辅助水蒸汽结合上浮溶剂固化法快速萃取谷物中三嗪类除草剂

Rapid Extraction of Triazine Herbicides in Cereal by Microwave-assisted Steam Extraction Combined with Solidification of Floating Organic Drop Method

建立了简单、灵敏和绿色的方法用于谷物样品中6种三嗪类除草剂的快速分析。谷物样加入适量正十二醇,在微波辅助下,三嗪类除草剂被水蒸汽萃取出来,收集到含有NaCl的冷凝管中作为萃取液。萃取液经过充分搅拌,在冰水浴中冷冻后,将富集有三嗪类除草剂的正十二醇固体转移至离心管中,融化后,过滤,利用高效液相色谱-串联质谱检测三嗪类除草剂。对微波辅助水蒸汽萃取和上浮溶剂固化萃取的实验条件进行了优化,得到最优的实验条件为:微波萃取功率800 W;萃取液收集体积12 mL;上浮溶剂为140μL正十二醇;加入NaCl 2.0 g;萃取液p H=7。检测6种三嗪类除草剂的线性范围为2.0～200 ng/g,相关系数为0.9979～0.9998;方法的检出限为0.28～0.61 ng/g;回收率为82.2%～99.6%;日内和日间相对标准偏差为2%～7%和3%～6%。相比于常规方法,本方法结合了微波辅助、水蒸汽萃取和上浮溶剂固化萃取3种技术的优点,更环保、快速、简便,且具有处理成本低、富集倍数高、有机溶剂用量少等特点,适用于复杂固体样品中三嗪类除草剂的分析。

A simple sensitive and green method was established for the rapid determination of six kinds of triazine herbicides in cereal samples.The method combined the advantages of microwave assisted extraction,water steam extraction and floating solvent extraction.Certain amount of dodecanol was added to the sample in the extraction vessel,and then triazines were extracted by water steam under microwave energy,after that,sodium chloride was added into the extract liquor.After the extract liquor was thoroughly stirred and put into the ice-water bath,the sample scoop was taken out and the dodecanol solid of triazine herbicide was removed and transferred to the centrifuge tube.After thawing,the content was filtered,and then triazine herbicides were tested by liquid chromatography tandem mass spectrometry.In the experiment,the experimental conditions of microwave assisted water steam extraction and solidification of floating organic drop were optimized.Under the optimal experimental conditions such as 800 W of microwave extraction power,12 mL of extract liquor volume,140μL of dodecanol as floating solvent,2.0 g of NaCl and extract liquior at pH 7,the linearity region for detection of six triazine herbicides was 2-200 ng/g,with correlation coefficient of 0.9979-0.9998.The limits of detection and the recoveries of triazines were 0.28-0.61 ng/g and 82.2%-99.5%,respectively.The relative standard deviations of intra-day and inter-day variations were 2%-7%and 3%-6%,respectively.Compared with the traditional extraction method,the proposed method was more environmentally friendly,rapid in detection and simpler in operation.Besides,the method had many advantages such as low cost,high concentration fold and low organic solvent,and could be used for detection of triazine herbicides in complex solid samples.