磁性石墨烯纳米粒子固相萃取与气相色谱-质谱相结合测定环境水样中的三嗪类除草剂

将磁性石墨烯作为磁性固相萃取的吸附剂与气相色谱-质谱(GC-MS)相结合建立了环境水样中7种三嗪类除草剂残留的测定新方法。对影响萃取效率的一些因素如吸附剂用量、萃取时间、样品溶液的pH值、离子强度和解吸条件等进行了优化。在优化的实验条件下,7种三嗪类除草剂的富集倍数在574~968之间。测定西玛津、扑灭津、嗪草酮、西草净、氰草津的线性范围为0.01~10.0μg/L,莠去津的线性范围为0.05~10.0μg/L,扑灭净的线性范围为0.01~8.0μg/L。线性相关系数为0.996 8~0.999 8,检出限(S/N=3)为1.0~5.0ng/L。将本方法应用于井水、自来水和湖水等实际水样的分析,在0.5μg/L和2.0μg/L下的加标回收率为79.8%~118.3%,相对标准偏差为3.6%~10.5%。该法操作简单、富集倍数高,可满足水样中三嗪类除草剂残留的检测要求。

Extraction of triazine herbicides from environmental water samples with magnetic graphene nanoparticles as the adsorbent followed by determination using gas chromatography-mass spectrometry

A novel method was developed for the determination of seven triazine herbicides in environmental water samples by magnetic solid-phase extraction with graphene-based magnetic nanoparticles (G-Fe₃O₄ MNPs) as the adsorbent coupled with gas chromatography-mass spectrometry detection. The main factors influencing the extraction efficiency including the amount of G-Fe₃O₄, the extraction time, the pH and the ionic strength of sample solution and the desorption conditions were optimized. Under the optimized experimental conditions, the enrichment factors of the method for the analytes were in the range from 574 to 968; the linearities of the method ranged from 0.01 to 10.0 μg/L for simazine, propazine, metribuzin, simetryn and cyanazine, from 0.05 to 10.0 μg/L for atrazine and from 0.01 to 8.0 μg/L for prometryn, with the correlation coefficients (r) ranging from 0.9968 to 0.9998. The limits of detection were in the range between 1.0 and 5.0 ng/L. Good reproducibilities were obtained with the relative standard deviations below 10.5%. The developed method was applied to the analysis of the triazine herbicides in different water samples (lake, well and tap). The recoveries of the method were in the range from 79.8% to 118.3% at the spiked levels of 0.5 μg/L and 2.0 μg/L. The results indicated that the developed method can be used as a simple and efficient technique for the determination of the triazine herbicides in environmental water samples.