A highly sensitive dispersive microextraction method with magnetic carbon nanocomposites and two miscible stripping solvents followed by GC-µECD for quantification of 32 polychlorinated biphenyls in various real samples

Polychlorinated biphenyls (PCBs) are an important class of organic pollutants consists of 209 different species. Due to their wide distribution, persistence and toxicity in the environment, PCBs are an environmental problem has been more than three decades as the main indicators of environmental quality and human health are considered. [1]. Owing to their very poor aqueous solubility, PCBs concentration levels in water are usually very low. Also due to lipophilicity of PCBs, fishes can absorb, retain and concentrate them, particularly in fatty tissues [2]. In the present research, a highly sensitive dispersive microextraction method was performed with magnetic carbon nanocomposite and two miscible organic solvents (MSPE-DLLME) prior to gas chromatography equipped with micro electron capture detector (GC-µECD) for simultaneous determination of 32 polychlorinated biphenyls (PCBs) in various real samples. In order to obtain high extraction efficiency, the parameters affecting MSPE-DLLME such as the pH of sample solution for both MSPE and DLLME steps, amount of sorbent, extraction time, type and volume of two miscible organic solvents and salt addition were optimized. Comparing to the previous procedures, the proposed method performs high sensitivity and pre-concentration factor and good accuracy. The proposed method was applied to the simultaneous analysis of residues in real samples. The results showed that this method is simple, rapid, and highly sensitive compared to all previous reported analysis methods accomplished in the meanwhile.