Studies On The Determination Of Three Kinds Of Carcinogenic Aromatic Amine By Interface Potentiometry With Double Poles Based On Imprinting

The current detection methods of carcinogenic aromatic amines include chromatography,spectroscopy,traditional electrochemical analysis and so on.Chromatography has relatively high selectivity,but the instrument is expensive and the sample pretreatment process is more complex,which making the testing cycle is longer and higher cost,do not adapt to the trend of rapid detection of modern.Although the high sensitivity of spectroscopy and traditional electrochemical analysis are,the selectivity is poorer and the detection range is narrower.In addition,it is also needed to synthesize the new reagent in the determination of spectroscopy,so that the measurement procedures become cumbersome.Therefore,it is necessary to develop a new technique which is simple operation,good selectivity and high sensitivity for the detection of carcinogenic aromatic amines.Interface potentiometry with double poles is a simple and sensitive new method to analyze the interfacial potential in recent years.It is based on the change of the interfacial potential by the interaction between the electrode material and the material to be measured,and then resulting the change of the potential of the current is zero,which is zero current potential(Zero Current Potential,ZCP)so as to realize the detection and analysis of the material to be measured.Molecular imprinted polymer(MIP)has high selectivity and specificity,which can identify the target molecule(template molecule).In this paper,a simple and sensitive method of interface potentiometry with double poles was combined with the high selectivity of molecular imprinted polymers,three kinds of carcinogenic aromatic amines molecularly imprinted polymers were prepared on the surface of graphite modified pencil core electrode by optimizing the best preparation conditions for interface potentiometry with double poles,which used three kinds of carcinogenic aromatic amines(4,4'-Oxydianiline,4,4'-Thiodianiline,3,3'-Dimethoxybenzidine dihydrochloride)as template molecule.The preparation conditions of molecular imprinted polyme were optimized by the interface potentiometry with double poles,we constructed 4,4'-Oxydianiline-MIP,4,4'-Thiodianiline-MIP and 3,3'-Dimethoxybenzidine dihydrochloride-MIP on the surface of graphene modified pencil electrode.With the help of high selective recognition molecularly imprinted polymers to template molecules,a new method for the determination of three kinds of carcinogenic aromatic amine by interface potentiometry with double poles based on imprinting was established.Besides,the adsorption kinetics and thermodynamic mechanism of three kinds of carcinogenic aromatic amines imprinted polymers were studied by interface potentiometry with double poles,the imprinted parameters(imprinting capacity and imprinting factor)of three kinds of carcinogenic aromatic amines were calculated.It is researched as follows:1.A new technique for the determination of three kinds of carcinogenic aromatic amine by interface potentiometry with double poles based on imprinting was established.(1)The preparation conditions were optimized by the interface potentiometry with double poles.The 4,4'-Oxydianiline-MIP was prepared by 5.0×10-3 mol·L-1 4,4'-Oxydianiline was used as template molecule,2.0×10-2 mol·L-1 acrylamide was used as functional monomer,pH6.81 phosphate buffer saline as the supporting electrolyte,using cyclic voltammetry to circular 18 times in scanning in the potential range of-1.2-1.2 V and the rate of 0.1 V·s-1.The 4,4'-Thiodianiline-MIP was prepared by 5.0×10-4 mol·L-1 4,4'-Thiodiani line was used as template molecule,3.0×10-3 mol·L-1 acrylic acid was used as functional monomer,pH6.64 phosphate buffer saline as the supporting electrolyte,using cyclic voltammetry to circular 16 times in scanning in the potential range of-1.2-1.2 V and the rate of 0.1 V·s-1.The 3,3'-Dimethoxybenzidine dihydrochloride-MIP was prepared by 6.0×10-4 mol·L-1 3,3'-Dimethoxybenzidine dihydrochloride was used as template molecule,3.6×10-3 mol·L-1 Methyl methacrylate was used as functional monomer,pH6.98 phosphate buffer saline as the supporting electrolyte,using cyclic voltammetry to circular 24 times in scanning in the potential range of-1.0-1.0 V and the rate of 0.1 V·s-1.(2)Linearity range,linear equation,detection limit of three kinds of carcinogenic aromatic amine.The linear range is 1.0×10-7-1.0×10-3 mol·L-1,the linear equation is:EZCP=(0.0237±0.0010)log[C4,4'-oxydianline]+(0.2320±0.0003)(R2=0.9940±0.0016,n=9)and the detection limit is 4.71×10-8mol·L-1 of 4,4'-Oxydianiline.The linear range is 1.0×10-8-1.0×10-4 mol·L-1,the linear equation is:EZCP(0.0162±0.0017)log[C4,4'-Thiodianiline]+(0.1881±0.0027)(R2=0.9924±0.0029,n=9)and the detection limit is 4.32×10-9 mol·L-1 of 4,4'-Thiodianiline.The linear range is 1.0×10-8-1.0×10-4 mol·L-1,the linear equation is:EZCP=(0.0182±0.0006)log[C3,3'-Dimethoxybenzidine dihydrochloride]+(0.1479±0.0030)(R2=0.9933±0.0029,n=9)and the detection limit is 6.49×10-9 mol·L-1 of 3,3'-Dimethoxybenzidine dihydrochloride.(3)Analytical applicationWhen was used to detect the 4 4'-Oxydianiline in wastewater samples,the recovery is 91.63%-101.21%,which is consistent with standard chromatography mothod.When was used to detect the 4,4'-Thiodianiline in wastewater samples,the recovery is 95.50%-103.25%,which is consistent with standard chromatography mothod.When was used to detect the 3,3'-Dimethoxybenzidine dihydrochloride in wastewater samples,the recovery is 98.50%-103.67%,which is consistent with standard chromatography mothod.2.Studies on the adsorption kinetics and thermodynamic of three kinds of carcinogenic aromatic amines and the imprinted parameters(imprinting capacity and imprinting factor)of imprinted polymers were calculated.(1)The adsorption kinetics and thermodynamicAt 298K,it is the Freundlich model of the adsorption between 4,4'-Oxydianiline and the imprinted polymer.The adsorption kinetic is in accordance with the pseudo-second model,and the rate constant is 0.0552 s-1.The obtaining the thermodynamic parameters were ?G=-7.7548 KJ/mol,?H=24.1487 KJ/mol,AS=103.7030 J/(mol·K).At 298K,it is the Freundlich model of the adsorption between 4,4'-Thiodianiline and the imprinted polymer.The adsorption kinetic is in accordance with the pseudo-first model,and the rate constant is 0.0115 s-1.The obtaining the thermodynamic parameters were?G=-8.4510KJ/mol,?H=24.0449 KJ/mol,?S=109.0466 J/(mol·K).At 298K,it is the Freundlich model of the adsorption between 3,3'-Dimethoxybenzidine dihydrochloride and the imprinted polymer.The adsorption kinetic is in accordance with the pseudo-first model,and the rate constant is 0.0093 s-1.The obtaining the thermodynamic parameters were ?G=-8.8920 KJ/mol,?H=24.1264 KJ/mol,?S=110.8000 J/(mol·K).(2)The imprinted parametersThe imprinting capacity of 4,4'-Oxydianiline and its structure of 4,4'-Thiodianiline,4,4'-Methylene-bis(2-chloroaniline),2,4-Diaminotoluene,5-nitro-o-toluidine,on the imprinted polymer were 0.4380±0.0170,0.1306±0.0061,0.1454±0.0057,0.0558±0.0039,0.0730±0.0036,and imprinting factor is 2.77,1.46,1.52,1.45,1.14.The imprinting capacity of 4,4'-Thiodianiline and its structure of 4,4'-Oxydianiline,5-nitro-o-toluidine,4,4'-Methylene-bis(2-chloroaniline),p-Aminoazobenzene,2,4-Diaminotoluene on the imprinted polymer were 0.7360±0.0199,0.5263±0.0199,0.399±0.0093,0.0454±0.0186,0.1495±0.0191,0.1040±0.0139 and imprinting factor is 1.74,1.36,1.33,1.29,1.19,1.17.The imprinting capacity of 3,3 '-Dimethoxybenzidine dihydrochloride.and its structure of 4,4'-Thiodianiline,4-Aminodiphenyl,o-methoxyaniline,4,4'-Oxydianiline,4-Chloroaniline on the imprinted polymer were 0.6815±0.0279,0.4242±0.0577,0.2427±0.0066,0.3222±0.0401,0.5411 ±0.0725,0.4014±0.0142 and imprinting factor is 2.04,1.48,1.23,1.36,1.03,1.17.