Study On The Determination Of Trace Amounts Of Metal Impurities In High Purity Silver Nitrate

Silver nitrate is a very important product of chemical industry.lt is widely used in many industries.especially sensitive industry. As the raw materials in sensitive industry,some impurities in high purity silver nitrate will have a bad effect on sensitivity.Therefore,the manufacturing of high quality silver nitrate are very important for the development of sensitive industry.We must have the strict quality-control analysis for high purity silver nitrate.In the thesis,the determination of trace amounts of 11 metal impurities (Cu,Fe, Pb,Bi,Au,Pd,Ni,Mn,Cd,Cr and Hg) in high purity silver nitrate by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) was throughly studied.The optimum working conditions for determination of Cu,Fe,Pb,Bi,Au!.PdrNi, Mn,Cd,Cr and Hg in high purity silver nitrate after seperation by precipitation with hydrochloric acid or by complexing with EDTA and precipitation with ammonium chloride were studied.Under the optimum condition for ICP-AES,the detection limits of Cu,Fe,Pb,Bi,Au,Pd,Ni,Mn,Cd,Cr and Hg were 40ng/mL,50 ng/mL,75 ng/mL,65 ng/mL,70 ng/mL,110 ng/mL,25 ng/mL,50 ng/mL,65 ng/mL,50 ng/mL and 100 ng/mL respectively.The recoveries were found to be 86.6%~ 105.4% and the RSD to be 2.79%~4.33%. Under the optimum conditionfor ICP-MS, the detection limits of Cu,Fe,Pb,Bi,Au,Pd,Ni,Mn, Cd,Cr and Hg were 0.15ng/mL,0.15 ng/mL,0.3 ng/mL,0.3 ng/mL,0.25 ng/mL,0.6 ng/mL,0.1 ng/mL,0.2 ng/mL,0.4 ng/mL,0.2 ng/mL and 0.5 ng/mL respectively. The recoveries were found to be 85.4%~93.3% and the RSD to be 0.96%~ 2.54%.The method has been applied to analysis of trace amounts of metal impurities in high purity silver nitrate,and the results abtained are satisfactory.In the thesis,a new sample pretreatment method wich have not been published in leading scientific journals was brought forward.The method is simple,easy for use,low blank value,simultaneous determination for impurities and low acid operation.Based on the thesis,we constitute the method for determination of trace amounts of 11 metal impurities in high purity silver nitrate by ICP-MS. This method has been applied as control analysis in the producing process,and also in the identification of final products. This method is not only suitable for determination of trace amounts of impurities in high purity silver nitrate,but also in high purity silver and other high purity precious metals.