Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
Anal Chim Acta. 2014 Mar 3;814:69-78. doi: 10.1016/j.aca.2014.01.037. Epub 2014 Jan 19.
A novel solid phase microextraction (SPME) fiber was prepared and coupled with gas chromatography corona discharge ion mobility spectrometry (GC-CD-IMS) based on polypyrrole/montmorillonite nanocomposites for the simultaneous determination of diazinon and fenthion. The nanocomposite polymer was coated using a three-electrode electrochemical system and directly deposited on a Ni-Cr wire by applying a constant potential. The scanning electron microscopy images revealed that the new fiber exhibited a rather porous and homogenous surface. The thermal stability of the fabricated fiber was investigated by thermogravimetric analysis. The effects of different parameters influencing the extraction efficiency such as extraction temperature and time, salt addition, stirring rate, the amount of nanoclay, and desorption temperature were investigated and optimized. The method was exhaustively evaluated in terms of sensitivity, recovery, and reproducibility. The linearity ranges of 0.05-10 and 0.08-10 μg L(-1), and the detection limits of 0.020 and 0.035 μg L(-1) were obtained for diazinon and fenthion, respectively. The relative standard deviation values were calculated to be lower than 5% and 8% for intra-day and inter-day, respectively. Finally, the developed method was applied to determine the diazinon and fenthion (as model compounds) in cucumber, lettuce, apple, tap and river water samples. The satisfactory recoveries revealed the capability of the two-dimensional separation technique (retention time in GC and drift time in IMS) for the analysis of complex matrices extracted by SPME.
一种新型固相微萃取（SPME）纤维被制备出来，并与基于聚吡咯/蒙脱土纳米复合材料的气相色谱电晕放电离子迁移谱（GC-CD-IMS）耦合，用于同时测定敌敌畏和倍硫磷。纳米复合材料聚合物通过三电极电化学系统进行涂覆，并通过施加恒电位直接沉积在镍铬丝上。扫描电子显微镜图像显示，新纤维具有相当多孔和均匀的表面。通过热重分析研究了制备纤维的热稳定性。考察和优化了不同参数对萃取效率的影响，如萃取温度和时间、加盐、搅拌速度、纳米粘土的量和解吸温度。该方法从灵敏度、回收率和重现性等方面进行了全面评估。对于敌敌畏和倍硫磷，分别获得了 0.05-10 和 0.08-10 μg L(-1)的线性范围和 0.020 和 0.035 μg L(-1)的检测限。日内和日间的相对标准偏差值分别计算为低于 5%和 8%。最后，该方法被应用于测定黄瓜、生菜、苹果、自来水和河水样品中的敌敌畏和倍硫磷（作为模型化合物）。令人满意的回收率表明二维分离技术（GC 中的保留时间和 IMS 中的漂移时间）对于通过 SPME 提取的复杂基质的分析具有能力。
