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从色谱条件、溶剂置换条件和萃取液浓缩方式等对水中16种PAHs的液液萃取-液相色谱方法进行了优化研究.结果显示,超高压液相色谱的分析时间(20 min)和消耗的有机溶剂(6.6 mL)分别为高效液相色谱的59%和18%,其标准曲线的线性关系、仪器的精密度和灵敏度也优于高效液相色谱,但对部分PAHs不能实现基线分离.二氯甲烷会引起苯并(a)芘和苯并(g,h,i)苝荧光信号的显著增强,加入5 mL乙腈可使溶剂中的二氯甲烷置换充足,避免荧光信号的异常.氮吹过程中,剩余体积需保持在0.2 mL以上,以减少2—3环PAHs的损失.对于大体积萃取液的浓缩方式,旋转蒸发法可减少2—3环PAHs的损失,使16种PAHs的平均回收率(99.6%)高于氮吹法(77.6%).两种加标水平的实验结果显示16种PAHs的回收率为84.2%—108.5%(RSD 2.2%—7.3%).优化后的方法稳定可靠,可为广大环境监测及科研人员准确分析水中16种PAHs提供参考.
The liquid-liquid extraction (HPLC) method of 16 PAHs in water was optimized from the aspects of chromatographic conditions, solvent replacement conditions and the concentration of extraction solutions. The results showed that the analysis time of ultra-high pressure liquid chromatography (20 min) The organic solvent (6.6 mL) was 59% and 18% of the HPLC respectively. The linearity of the standard curve and the precision and sensitivity of the instrument were also better than that of the HPLC, but some PAHs could not be separated by baseline. Methylene chloride causes a significant increase in the fluorescence signal of benzo (a) pyrene and benzo (g, h, i) perylene, adding 5 mL of acetonitrile can make sufficient replacement of methylene chloride in the solvent to avoid the abnormal fluorescence signal. In the process, the remaining volume should be kept above 0.2 mL, in order to reduce the 2-3 ring PAHs loss.For large volume extract concentrated, rotary evaporation method can reduce the 2-3 ring PAHs loss, the average of 16 PAHs The recoveries (99.6%) were higher than those for nitrogen (77.6%). The experimental results of the two spiked levels showed that the recoveries of 16 PAHs ranged from 84.2% to 108.5% (RSD 2.2% -7.3%). Stable and reliable, for the majority of environmental monitoring and scientific research personnel accurate analysis of 16 PAHs in water provide a reference.