| The pollution of automobile exhaust had became one of the main pollutions in the cities. In order to control the pollution, all countries were taking some measures to decease the release of harmful components in the waste gases, such as CO, NOX, and so on. The platinum group elements, including platinum, palladium and rhodium, were effective components in " three effect catalyzer". They could convert the harmful gases to harmless materials. However, a part of platinum group metals would release to the environment at the same time. They might be absorbed by plants, animals and human beings. The paper included five parts:Chapter one introduced the physiological function, analytical methods and the principles of platinum, palladium and rhodium, summarized the recent advance of analysis of platinum, palladium and rhodium in the world and the content in the environmental dust in city areas and highway.Chapter two studied and established a simple method for the determination of trace Pt(IV) by the spectrophotometry with 5-[(5 -chloro - 2-pyridinal)azo]-2,4-diaminotoiuene as color reagant. The Pt in GBW07293 earth chemical standard material of noble group elements was determined. Beer's law was obeyed in the concentration range of 0.03-1.1 ng/mL and the limit of detection was 13.8 ng/mL.Chapter three studied the selective absorption of the polyurethane foam plastics to palladium. Palladium could be enriched on the foam plastics. The foam plastics were decomposed by HNO3, HCIO4. The final solution is determined by GFAAS. The linear relation between concentration and signal was found in the range of 0-72 ng/mL, R=0.99843. The developed method was implied in analysis of ore and soil samples and the recoveries were 98.1 %-107.6%.Chapter four studied and established the method for determination of Pt Rh Pd in street dust by inductively coupled plasma mass spectrometry (ICP-MS). The digested method for the samples was studied digests and aqua regia was selected to digest the samples. The linear relation and parallel were found fine. The limit of detection were Pt 0.48ng/g Rh 0.42ng/g Pd 4.22ng/g and the recoveries were Pt 87.6%-88% Rh93%-95% Pd 85.2%-87.8% with satisfactory. Chapter five studied the contents of Pt, Rh, Pd in dust samples from city area and part of suburb. The samples were collected from the second ring, the third ring road and the fifth ring road in Beijing City area, and the soil in farmland and in Wu Ling Mountain in Mi Yun suburb. Pt, Rh, Pd in samples were determined by ICP-MS developed in Chapter four. The result showed that it contained reletive high level of Pt, Rh, Pd in the environmental dust in Beijing, and the content of Pt was 10.4-235.95 ng/g, Pd 6.61-115.82 ng/g, Rh 4.21-39.48 ng/g. The content of determined elements were very low in suburb, as the backgound value. The contents in second ring and third ring roads were higher than in fifth ring road. Among them, the content was highest in Fuxing Men to Guanyuan Bridge to Xizhi Men and the concentration of Rh was 16.7 times of the backgound value, Pd was 5.6times, Pt was 194.4 times. It had close relation with its heavy traffics. More cars, more release of the platinum group metals. |
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