Electrochemical Sensing Of Polycyclic Aromatic Hydrocarbons Exposure Biomarkers Based On Zeolitic Imidazolate Frameworks Composite Materials

Polycyclic aromatic hydrocarbons(PAHs)are recognized as persistent pollutants globally.Human exposure to PAHs through various ways such as respiratory tract,digestive tract and skin contact,which can lead to the declined pulmonary function,metabolic disorders and reproductive toxicity.In addition,they are also carcinogenic,teratogenic and mutagenic.In this paper,we constructed two new electrochemical sensors based on zeolitic imidazolate frameworks nanomaterials to analyze 1-hydroxypyrene,which was the metabolite of PAHs for evaluating the level of human exposure to PAHs.The research focused on the following aspects:(1)In this work,a simple sensor based on nano-carbon paste electrode modified with zeolitic imidazolate frameworks(ZIF-8)/ionic liquid composites was developed for convenient and fast electrochemical detection of 1-OHP.The structure of ZIF-8 and the morphologies of different electrodes were investigated by transmission electron microscopy(TEM)and scanning electron microscopy(SEM).The electrochemical behavior of l-OHP on the constructed modified electrode was studied using differential pulse voltammetry(DPV),and the results showed that the ZIF-8/nano-CILE presented better electrocatalytic activity towards 1-OHP.Under the best conditions,the prepared sensor gave a linear calibration curve of the concentration in the range of 0.05-20 μM with a detection limit of 0.01 μM for 1-OHP.The proposed method was successfully applied to the determination of 1-OHP in urine samples with the recoveries of 94.2%-103.2%.(2)In this work,we improved the properties of the modified material on the basis of the previous work.The colloidal gold was introduced to improve the electrical conductivity of zeolitic imidazolate frameworks-67(ZIF-67).A colloidal gold modified zeolitic imidazolate frameworks-67/carbon nanofiber paste electrode(Au@ZIF-67/CNFPE)was fabricated for the rapid and sensitive detection of 1-OHP.The morphologies of carbon nanofibers(CNF),ZIF-67,colloidal gold and colloidal gold@ZIF-67(Au@ZIF-67)were studied by transmission electron microscopy(TEM).The electrochemical behavior of 1-OHP was investigated by square wave voltammetry(SWV).The effect factors like pH value,amount of colloidal gold,accumulation potential and accumulation time were optimized.Under the optimal conditions,the constructed sensor responded to 1-OHP linearly in the concentration range of 0.0005-10 μM,and the detection limit was as low as 0.1 nM.The results demonstrated that the sensor exhibited good reproducibility,stability and selectivity.Finally,the electrode was successfully applied for the analysis of 1-OHP in human urine samples.