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固相萃取-液相色谱/质谱法测定地下水中三嗪类和

Determination of Herbicide Residues in Groundwaters Using Liquid/Liquid Extraction and Off-line Purification with Liquid Chromatography-Mass Spectrometry

  • 摘要: 固相萃取-液相色谱/质谱法是三嗪类和酰胺类除草剂常用的检测方法。本文针对现有分析方法仪器分析时间较长的缺点,以HLB柱为固相萃取柱,二氯甲烷-丙酮混合液(V : V=4 : 1)为洗脱剂,氟罗里硅土柱为净化柱,采用快速液相色谱柱,建立了固相萃取-液相色谱/质谱法快速测定地下水中14种三嗪类和2种酰胺类除草剂的方法。实验考察了固相萃取柱、定量离子扫描时间、富集柱洗脱溶剂、净化柱等因素对三嗪类和酰胺类除草剂测定的影响。通过延长定量离子的扫描时间,可以降低大部分目标化合物的相对标准偏差,提高仪器的稳定性;富集柱洗脱溶剂的极性对目标化合物回收率有较大影响,使用较强极性的二氯甲烷-丙酮(V : V=4 : 1)洗脱剂可以获得较高的目标化合物回收率;采用氟罗里硅土柱对萃取液进行净化,可除去干扰物,降低基体效应的影响。研究结果表明,14种三嗪类除草剂和2种酰胺类除草剂的检出限均小于0.40 μg/L,在低、中、高三种添加浓度下,回收率均满足要求。本方法虽然色谱峰重叠较多,但仪器分析时间为5.10 min,与现有方法的仪器分析时间(15 min以上)相比,分析时间短,检出限低,能够满足日常环境水样中农药残留分析检测的需要。

     

    Abstract: Solid phase extraction-Liquid Chromatography-Mass Spectrometry is a commony method for the determination of triazine and amides herbicides in groundwater. In order to overcome the disadvantage of the long processing time for current analysis procedure and instruments, a new method has been established, which uses HLB solid-phase extraction, elution reagents of methylene chloride-acetone (V : V=4 : 1) and a fluorine florisil column as the purification column. 14 kinds of triazine and 2 amides herbicides in groundwater were measured by Liquid Chromatography-Mass Spectrometry. The influence factors of mass spectrum conditions, solid-phase extraction column, elution solvents and purification columns were studied. Extending the scanning time of quantitative ions can reduce the relative standard deviation for most of the target components, and improve the stability of the instrument. The polarity of elution solvents greatly influences the recoveries of target components. Methylene chloride-acetone (V : V =4 : 1), which is more polar solvent, can obtain higher recoveries. The fluorine florisil column was used to remove interfering substances, reducing the matrix effect. The results show that the detection limits of 14 kinds of triazine herbicide and 2 amide herbicideare are less than 0.40 μg/L. The results are accurate and stable, with the recoveries of all herbicides between 85.8%-103.1% at 0.50 μg/L, and relative standard deviations between 5.2%-8.6%. However, this method has a lot of overlap peaks, but the analysis time is significantly shorter than current methods (5 min compared to 15 min or more), and meets the daily needs of large quantities of water sample testing.

     

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