植烟土壤中16种多环芳烃的洗脱净化技术及含量测定

Elution and purification of 16 polycyclic aromatic hydrocarbons in tobacco-planting soil and the content determination

为测定植烟土壤中16种多环芳烃(PAHs)的含量,建立并优化了土壤样品的洗脱净化方法,比较了不同洗脱剂、净化方法及净化条件的提取效果。结果表明,3种洗脱剂中正己烷-二氯甲烷混合液(体积比1∶1)洗脱效果最好,四通道色谱分离仪法在提取效果、溶剂耗量、操作时间上均优于硅胶柱法。在最佳操作条件下(洗脱剂用量2 m L/次、洗脱时间50 s/次)洗脱5次后采用气相色谱—质谱联用仪对16种PAHs进行检测,16种PAHs均在20~2 000μg/L内呈线性关系(R>0.99),仪器检出限为0.72~2.09μg/L,植烟土壤中16种PAHs的加标回收率为80.3%~114.4%,相对标准偏差为4.2%~12.3%。该方法简便、高效,能准确测定出植烟土壤中16种PAHs的含量。

In order to determine the content of 16 polycyclic aromatic hydrocarbons（ PAHs） in tobacco-planting soil,a method for elution and purification of soil sample was established and developed. The effect of different eluent,purification method and purification conditions on purification efficiency was studied. Results showed that n-hexane-methylene chloride mixture（ volume ratio 1∶ 1） achieved the best purification efficiency in 3 eluents. The method of using four-channel purification chromatography instrument presented the better performance in purifying effect,solvent consumption and operation time compared with silica gel column method. Eluting the soil samples under the optimum operating conditions（ eluent flow rate of 2 m L/time and elution time of 50 s/time） for 5 times,and then gas chromatography（ GC）-mass spectrum（ MS） was applied to detect the 16 PAHs in soil. Results showed that all the 16 PAHs were well separated and purified,the calibration curves had a good linear relationships（ R〉0. 99） between 20-2 000 μg/L. The detection limit was ranged 0. 72-2. 09 μg/L,the recovery rate of 16 PAHs in soil sample was 80. 3%-114. 4% and the relative standard deviation（ RSD） was 4. 2%-12. 3%.The established method was convenient and efficient,which could determine the content of 16 PAHs in tobacco-planting soil accurately.