| Metal barium is almost not toxic, but soluble barium salt such as BaCl2, BaNO3,etc.（BaCO3formed BaCl2,when meet stomach acid, can absorb by thegastrointestinal） is virulent, can lead to serious poisoning after eating. Long-termcontact, or inhaled will also bring harm to the body. But barium is extensive widely inthe nature, including air, water, and food.Therefore, the detection of barium ion isparticularly important.This paper researches dissociate barium ion by two ways of electrochemicalsolid phase microextraction cyclic voltammetry and fluorescence spectrometry, andachieves the following results.Electrochemical solid phase microextraction is a powerful tool in samplepretreatment, and can be used in the electrochemical detection of electrochemicallyinactive substances. In the present paper, Barium ion was extracted electrochemicallyon a sodium rhodizonate modified carbon paste electrode based on the coordinationinteraction between sodium rhodizonate and Barium ion. The extraction process andits optimal experimental conditions were studied by cyclic voltammetry. Theextraction kinetics follows a sigmoidal model with the apparent first order kineticconstant of2.183min-1. The isothermal follows a Freundlich model with thethermodynamic adsorption constants of n=11.4，k=1.025. This study offers a basicdata for the electrochemical determination of barium cation.After the first theory, this paper determines the concentration of barium ion inbarium meal by electrochemical solid phase microextraction cyclic voltammetry.Under the optimization of the experimental conditions: pH is12, sweep speed is0.008V/s, the quiet time is50s, the sodium rhodizonate modified in carbon powder is5%,we can measured in the concentration of the barium ions for1.046×10-5mol/L,detection limit for1.05×10-5mol/L1.08×10-10mol/L. The result is consistent withconsistent with atomic absorption spectrometry. This method has low detection limit,high sensitivity, and is suitable for trace barium ion detection.The solubility of barium sulphate was determined by fluorescent spectrometrybased on the fluorescence of complex between barium and sodium rhodizonateunder the optimal conditions of pH11.2, reaction time of5min and ethanol volume ratio of15%in solvent. The fluorescence intensity of the complex shows two linearrelationships with the concentration of barium in the range of2.5×10-11～5.0×10-5mol/L with the lowest detection limit of2.5×10-11mol/L. The method wasused in the determination of solubility of barium sulphate in pure water, the result isaccord well with the value reported in the literature. |
PDF Full Text Request