粮谷中残留硝基苯的固相萃取前处理方法研究

Study on Pre-treatment Method of Nitrobenzene Residues in Grain by Solid Phase Extraction

根据不同种类粮谷的特点,低脂肪含量的样品采用正己烷直接提取的模式,高脂肪含量的样品先用乙腈作为提取剂,然后进行液-液分配,使硝基苯转移至正己烷相,正己烷提取液再利用固相萃取技术进行净化和浓缩处理;固相萃取选择氧化铝作为主要填料,用5ml正己烷和5ml乙酸乙酯-正己烷(6+4)淋洗杂质,最后乙酸乙酯进行洗脱并浓缩至5ml,使样品的浓缩和净化同步进行,解决了前处理过程中不能浓缩的问题,并用气相色谱-质谱进行了验证。实验本着简单、有效及节省成本的原则,利用固相萃取技术,解决了硝基苯净化和浓缩的问题,建立了一套理想的前处理方法,具有处理后杂质干扰少、实用性强等特点,通过对方法回收率进行验证,说明该方法准确、可靠,符合前处理要求。

A pre-treatment method of nitrobenzene was studied by solid phase extraction in grain. According to characteristic of different kinds of grain, nitrobenzene in low fatty grain was directly extracted by n-hexane, and high fatty grain was extracted with acetonitrile in pre-treatment procedures, then extraction of acetonitrile was transferred into n-hexane by liquid extraction method. Aluminum oxide was used as main stuffing in solid phase extraction, and weaker polar impurity was washed with nhexane and stronger polar particulate was washed with reagent of ethyl acetate- hexane （6＋4） respectively. Elution of stronger polar reagent that 5 ml ethyl acetate was used because of concentration demand, and the effect was perfect. Concentration and purity of the determination method of nitrobenzene were isochronous and the loss problem was resolved in pre-treatment procedures of concentration. The pre-treatment method was also confirmed by gas chromatographicmass spectrometry. A simple, available and economic pre-treatment method was established with the characteristics of low disturbance, convenience and high sensitivity in this study.