Fast Detection Of Heavy Metal Ions In Water System

The introduction of metal ions,conventional detection methods,electrochemiluminescence,fast-scan cyclic voltammetry were systematically reviewed.Fast-scan cyclic voltammetry is a powerful electrochemical analysis method,which can provide a fast response with subsecond temporal resolution.It has been used in the field of electrochemical analysis duo to fast detection speed and high sensitivity.In this paper,a series of methods for the detection of heavy metal ions based on fast-scan cyclic voltammetry were developed by the excellent electrochemical properties,which realized the highly sensitive detection of several heavy metal ions in the water system.The detailed contents were introduced as follows:1.Fast-scan anodic stripping voltammetry for detection of Pb?II?at picomolar levelFast-scan anodic stripping voltammetry?FSASV?was applied to sensitively detect Pb²⁺on a mercury film electrode?MFE?.The method was involved with a controlled preconcentration by accumulation of Pb²⁺on the MFE followed by FSASV measurement.At the scan rate of 500 V/s,a linear relationship between the anodic stripping peak current and the logarithm of Pb²⁺concentration in the solution was observed in the range from 0.1?mol/L to 0.1 pmol/L with a detection limit of 0.1 pmol/L.The proposed method was successfully applied for the determination of Pb²⁺in spiked water samples with satisfying recoveries in the range of 98.6 to 104.3%,and the corresponding relative standard deviation ranged from 3.7 to 5.5%.Therefore,FSASV is a sensitive,fast,cost-effective and simple method for the detection of Pb²⁺at picomolar level and would be very promising in heavy metal determination.2.Fast-scan adsorptive stripping voltammetry for selective detection of nickel ionsA fast,sensitive and selective electrochemical method was developed for the detection of nickel ion.This method was based on a complex of nickel ions and dimethylglyoxime?DMG?in an ammonium chloride electrolyte solution.Fast-scan adsorptive stripping voltammetry?FSAdSV?was applied to selectively detect Ni²⁺on a mercury film electrode?MFE?.At scan rate of 100 V/s,a linear relationship between the peak current and logarithm of Ni²⁺concentration was obtained in the range from 10^–66 mol/L to 10^–1414 mol/L with a detection limit of 10^–1414 mol/L.The method was successfully used for Ni²⁺determination in spiked tap water samples.A satisfactory recovery was acquired in the range of 94.8 to 105.2%with the corresponding relative standard deviation ranged from 4.3 to 6.4%.Therefore,FSAdSV is a sensitive,fast,selective and simple method for the Ni²⁺determination,and would be very promising in on-site analysis.3.An electrochemiluminescence/fast scan cyclic voltammmetry dual-mode electrochemical sensor detection of lead ions based on G-quadruplex DNAHerein,a novel electrochemiluminescence and fast scan cyclic voltammmetry dual-mode biosensor was successfully developed for the selective and highly sensitive detection of lead ion.The interaction between guanine residues and lead ions was confirmed by electrochemical impedance spectroscopy and cyclic voltammogram,and the G-quadruplex structure was formed.The results showed that the electron transfer between ferrocene labeled at the end of ssDNA and the electrode surface was enhanced by the folding of the oligonucleotides in the recognition layer due to the formation of the G-quadruplex structure.On the one hand,ferrocene signals were measured by fast-scan cyclic voltammetry?FSCV?to quantify lead ion concentration.On the other hand,DNA was folded on the surface of the gold electrode to prevent electron transfer between[Ru?bpy?₃]²⁺and the surface.Therefore,electrochemicalluminescence was used to determine the intensity of[Ru?bpy?₃]²⁺to quantify the concentration of lead ions.Under optimal conditions,the concentration of Pb²⁺could be determined by the FSCV within a linear range from 10^–66 mol/L to10^–1010 mol/L with a detection limit of 3.7×10^–1111 mol/L?S/N=3?as well as by monitoring the decreased ECL intensity of[Ru?bpy?₃]²⁺in a linear range of 10^–6mol/L to 10^–10mol/L with detection limit of 10^–1010 mol/L.Furthermore,the constructed dual mode biosensors was successfully applied for the Pb²⁺detection in spiked tap water samples.The satisfactory recovery varied from98.4%to 102.4%was presented,and the corresponding relative standard deviation?RSD?was obtained from 3.9%to 5.1%.Therefore,the dual mode electrochemiluminescence/voltammmetry electrochemical biosensors provided a potential for Pb²⁺analysis in real sample.