The Application Of Gold Nanoparticles To The Detection Of Mercury Ions

Mercury ion as a highly toxic heavy metal pollutant damages the central nervous system of human.Hence,the determination of mercury ions is significant.Conventional methods for the detection of mercury ions including atomic absorption,atomic fluorescence spectrum,and inductively coupled plasma-mass spectrometry?ICP-MS?suffer from expensive instrument and complicated sample preparation processes.In recently,some new methods such as electrochemical,fluorescent,chemluminescent,and colorimetric method were developed for the detection of mercury ions In the present study,we developed two gold nanoparticles Au NPs)based methods for the detection of mercury ions.Firstly,we developed a colorimetric method for the detection of mercury ions based on Au NPs.We found that the speed of Au NPs aggregation induced by MPBA was much faster than that of BDBA.The reaction between MPBA and Hg²⁺ions resulted in the formation MPBA-Hg²⁺-MPBA which was similar to BDBA having two free boronic acid groups.Based on the above phenomenon,a sensitive and selective colorimetric method for detection of mercury ions(Hg²⁺)in aqueous solution was developed.The linear range for the detection of Hg²⁺ions was from 0.08 to 1.25?M with a detection limit of 37 nM.The strategy offered excellent selectivity toward Hg²⁺against other metal ions.Meanwhile,this simple and cost-effective sensor was applied to determine the Hg²⁺in the lake samples with satisfactory recoveries?91.3-100.7%?.The simple,rapid,and sensitive label-free colorimetric sensor for the determination of Hg²⁺ions provided an attractive alternative to conventional methods which usually involve sophisticated instruments,complicated processes,and long periods of time.Secondly,we developed a chemiluminescent?CL?method for the detection of Hg²⁺based on Au NPs.It was found that ethylenediamine?EDA?could quench the CL intensity of the luminol-AgNO₃-Au NPs system.However,in the prensenc of Hg²⁺in solution,EDA would react with Hg² resulting in the decrease of quenching effect on the luminol-AgNO₃-Au NPs CL system and subsequent CL recovering.Therefore,the concentration of Hg²⁺can be detected by determining the CL intensity of the luminol-AgNO₃-Au NPs system.The linear range for the detection of Hg²⁺ions was from 0.001 to 1 pM with a detection limit of 0.54 fM.The strategy offered excellent selectivity toward Hg²⁺against other metal ions.Meanwhile,this simple and cost-effective sensor was applied to determine the Hg²⁺in tap water samples with satisfactory recoveries?72.43-105.53%?.Compared with the above colorimetric method,the sensitivity for the determination of Hg²⁺was improved drastically by using CL method.Finally,we prepared nano-corannulene particles which can be dispersed in water stably using a ultrasonic phase transfer method.We investigated the effect of polarity of organic solvent,pH of aqueous phase,and initial concentration of corannulene on the size and morphology of nano-corannulene particles.Then,the prepared nano-corannulene particles were characterized using TEM,UV-vis,IR,etc.And we also speculated the possible mechanism for the formation of nano-corannulene particles.