Studies On The Separation And Preconcentration Behavior Of Precious Metals In The Extraction Chromatography And Determination Of AAS

On the basis of numerous references, author has synthesized two types of extraction resin, namely dipped resin and levextrel resin. They have been used in the preconcentration and separation process of precious metals, respectively. The properties of extraction resins have been studied. The latter has been packed into the micro-columns, which was used in the FI-AA systems; on-line preconcentration and separation of precious metals have been achieved. In addition, the effect of matrix modifier agent, which was used in the direct determination of platinum, was discussed preliminarily.This paper consists of five chapters.In chapter 1, By means of extraction chromatography, the micro amounts of platinum and gold were separated from the common metal elements successfully. Using GDX501 resin dipped TBP as stationary phase. Platinum and gold preconcentrated in chromatographic column were eluted using 0.5mol/L HNO3-0.5mol/LNaClO3 and 0.1mol/LHCl-0.2mol/L thiourea as eluant respectively, and then separation and determination were carried out .The recoveries of platinum and gold were 89.5-113.9 % and 90.1-105.3 % ,3respectively.In chapter 2, a new synthetic method of Tri-n-octylamine (TOA) extraction resin and its analytical application to silver have been reported. This resin has been used in the preconcentration and separation process of silver in lead-zinc waste slag. Silver can be preconcentrated on the resin in Imol/LHCl, and separated from common metal elements; then eluted by 0.25mol/L NH4Cl-0.5mol/L thiourea, and determinated by FAAS. The recovery of silver was 99.44%~104.36%. The resin can preconcentrate 0.5ug/mL silver, and have a longer lifetime.In chapter 3, an efficient flow-injection on-line TO A extraction resin preconcentraction and separation system is proposed for the determination of trace silver by FAAS. The micro-column used was packed with TOA extraction resin, which was synthesized by author as stationary phase. Sample in 1.0mol/LHCl was pumped through a micro-column at the rate of 8.1mL/min. In the 60s sampling time and the 60s elution time, silver was absorbed and then eluted into the nebulizer of FAAS by 0.25mol/LHCl-0.5mol/Lthiourea. At the analytical frequency of 30/h, an enrichment factor of 26, a4concentration efficiency of 26/min and a consumptive index of 0.31mL were obtained. The linear calibration range was 0-1000μg/L. The detection limit (3ρ) was 1.2μg/L. The relative standard deviation at the 50μg/L levels was 1.4%. The proposed method has been applied to the determination of trace silver in lead-zinc waste slag and spectrum magnesium oxide reagent successfully.In chapter 4, a new manifold for on-line preconcentraction system with FAAS detection was progressed by author. The automatic preconcentraction and separation of trace palladium was achieved.The tri-iso-octylamine (TIOA) levextrel resin was packed into the micro-column as stationary phase. Sample in 0.5mol/LHCl waspumped through it at the rate of 7.8mL/min. In the 90s sampling time and the 45s elution time, palladium was absorbed and then eluted into the nebulizer of FAAS by 0.5mol/LHCl-0.1mol/L thiourea. At the sampling frequency of 40/h, an enrichment factor of 50, a concentration efficiency of 33/min and a consumptive index of 0.23mL were obtained. The linear calibration range was 0~1000μg/L. The detection limit (3ρ) was 0.34μg/L. The relative standard deviation at the ,50μg/L levels was 2.6%. The proposed method has5been applied in the catalyst sample analysis and recovery experiment. The recovery of Palladium was 99.27-101.2%.In chapter 5, a direct determination method of platinum in waste mine sand by graphite furnace atomic absorption spectrophotometerusing Vitamin C as a matrix modifier agent was reported. The effect of matrix modifier agent used was discussed preliminarily. The characteristic content was 1.3×10-10g/0.0044A. The linear range was 20~700ng-mL-1. The recovery was 93.9%~106 %.In a word, by numerous systematic and scrupulous experimental works, we...