New Protocols For Analysis Of Chloride Ion And Iodate Ion And Their Application

Halogen elements and their compounds play an important role in many fields such as being system,environmental testing and industrial production.It is an important significance to establish fast and accurate analysis method of halogen.In this work we have prepared a high-sensitive and selective chloride anion sensor and applied it to the determination of trace chloride anion in the photocatalytic degradation of organic pollutants.We have also synthesized the CdS quantum dots using Carboxyl methyl Cellulose sodium(CMC) as a stabilizer and used it as the fluorescent probe to detect iodate anion.The main contents as follows:(1) Polyvinyl chloride liquid membrane chloride anion selective electrodes based on a carrier phentobarbital chloride mercury(â…¡) were prepared in this paper.The interference of common anions was examined and it was found only I^-,Br^-,SCN^- and salicylate anion show a little interference,and the selectivity order of the electrode was I^-＞Br^-～SCN ^-～Salicylate^-＞＞ClO₄^-＞NO₃^-＞F^-＞H₂ PO₄^-＞HCO₃^-＞SO₄^2- At 25℃,the electrode has a linear response to chloride from 6.0×10^-3 to 3.5×10^-6mol/L,with a detection limit of 2.0×10^-6 mol/L and a slope of(57.6±2) mV/decade in 0.05 mol/L H₃PO₄-NaH₂PO₄,(pH 4.1) buffer solution.This method was applied to the determination of trace chloride anion in the solution of photo-degradation of chloroform with satisfactory results.(2) Inducing photo-degradation of chloroform by hydrogen peroxide has improved significan-tly in the presence of trace binary carboxylic acids(oxalic acid,1,3-propanedioic acid and succinic acid).The optimum conditions for the photo-catalysis degradation were as follows.The range of pH was 3.5 to 4.5,hydrogen peroxide was 3 to 10 mg/L and Fe(â…¢) was 0.2～0.45 mmol/L.Under the optimum conditions,the degradation rate of chloroform enhanced greatly.Chloride anion and hydrogen peroxide in the process of degradation of chloroform aqueous solution were monitored using Cl^- anion and H₂O₂ sensors respectively.(3) CdS QDs was synthesized in aqueous solution using CMC as a stabilizing agent via controlling the reaction time,pH and temperature of solution etc.The noval protocol for detection of IO₃^- anion was established based on the fluorescence quenching of the QDs. Under the optimum conditions,fluorescence quenching of the QDs was proportional to the concentration of IO₃^- anion,and the linear range of iodate anion concentration was 6×10^-8mol/L～5×10^-4 mol/L with a detection limit of 6×10^-8mol/L.