Lead in gasoline

As shown in Table 2.4, atomic absorption is extremely sensitive. It is particularly suited to the analyses of arsenic and lead in gasolines, for sodium in fuel oils (where it is the only reliable method) and for mercury in gas condensates. 

Anon. (1983), Assessment of the energy balances and economic consequences of the reduction and elimination of lead in gasoline . Working Group ERGA (Evolutions of Regulations, Global Approach). CONCAWE, La Haye. 

Care must be used in handling lead as it is a cumulative poison. Environmental concerns with lead poisoning has resulted in a national program to eliminate the lead in gasoline. 

Much of the bromine output in the U.S. was used in the production of ethylene dibromide, a lead scavenger used in making gasoline antiknock compounds. Lead in gasoline, however, has been drastically reduced, due to environmental considerations. This will greatly affect future production of bromine. 

AT the path length, and P (A) the mass absorption coefficient at wavelength A. Between absorption edges, P (A) is proportional to Z A and is nearly independent of physical or chemical state. An absorption measurement on each side of an absorption edge is required for each element analyzed. X-ray absorption is especially useful in determining heavy elements in mixed materials of lower Z, such as lead in gasoline and uranium in aqueous solution. 

Very careful analysis of trace elements can have a major effect on human life. A notable example can be seen in the career of Clair Patterson (1922-1995) (memoir by Flagel 1996), who made it his life s work to assess the origins and concentrations of lead in the atmosphere and in human bodies minute quantities had to be measured and contaminant lead from unexpected sources had to be identified in his analyses, leading to techniques of clean analysis . A direct consequence of Patterson s scrupulous work was a worldwide policy shift banning lead in gasoline and manufactured products. 

Some heavy metals and semi-metals are quite toxic (chromium, lead, and antimony) and expensive care is needed to prevent them from being dispersed in the environment. Lead in gasoline and paint has been... 

Test Methods for Lead in Gasoline Method 1-Standard method test for lead in gasoline by atomic absorption spectrometry Yes 40 CFR 80, App. B EPA 1974... 

Method 2-Automated method test for lead in gasoline by atomic absorption spectrometry ... 

Eisenreich SJ, Metzer NA, Urban NR, et al. 1986. Response of atmospheric lead to decreased use of lead in gasoline. Environ Sci Technol 20 171-174. 

D. R. Lunam, The Past, Present and Future of Lead in Gasoline, Ethyl Corp., Baton Rouge, LA, 1988. 

It is the view of this writer that for certain Main Group metallic elements, methylation in or by the environment has been demonstrated conclusively. Tin joins mercury and arsenic in this category. An insufficient number of observations has been made in the case of germanium (and also of antimony). To date, the lead case seems hopelessly bound up with the use of lead in gasoline and the final decision is still awaited in that case. It is more difficult if this comes down to proving the negative. 

Country Maximum lead in gasoline (gl 1) Consumption of gasoline (million tons) Consumption of organoleads (thousand tons)... 

X-ray methods include x-ray diffraction, x-ray absorption, and x-ray fluorescence. X-ray diffraction is a technique for determining ultrasmall spacings in materials, such as the spacings between the atoms or ions in a crystal structure, or the thickness of a thin electroplated material. An example of the former is in soil laboratories in which the minerals in various soils need to be characterized. X-ray absorption is limited in application, but has been used to determine heavy elements in a matrix of lighter elements, such as determining lead in gasoline. X-ray fluorescence is much more popular and is used to determine elements in a wide variety of solid materials. 

Nuclear magnetic resonance spectroscopy has been developed as a standard method for the determination of hydrogen types in aviation turbine fuels (ASTM D3701). X-ray fluorescence spectrometry has been applied to the determination of lead in gasoline (ASTM D2599) as well as to the determination of sulfur in various petroleum products (ASTM D2622, D4294). 

In the following discussion, three types of air pollutant analytical data will be examined using principal component analysis and the K-Nearest Neighbor (KNN) procedure. A set of Interlaboratory comparison data from X-ray emission trace element analysis, data from a comparison of two methods for determining lead In gasoline, and results from gas chromatography/mass spectrometry analysis for volatile organic compounds In ambient air will be used as Illustrations. 

The ASTM-EFA standard method of analyzing lead In gasoline requires extraction of alkyl lead Iodide complexes Into methyllsobutylketone and a subsequent flame atomic absorption analysis of the extract A more direct method has been proposed ( ) which uses Zeeman atomic absorption analysis after sample dilution. Both methods were used to analyze a set of five field collected samples. The results showed a bias (average difference between method results) of 0.0012 g/gal with the standard flame results higher. The correlation coefficient between the results was 0.9998 0.0009, and a pairwise t-test showed no difference between the methods (6). 

In other words, some uncertainty in the data should not be used as an excuse for inaction. This approach is being given more consideration in Europe than in the United States. The approach gains credibility when one considers how its application years ago would have prevented the tragic effects of lead in gasoline and paint. 

Lead aerosol in the air is poisonous to breathe, especially for young children. Many people called for the abolition of lead in gasoline. In the 1970s, the photochemical smog in California was attributed to unburned hydrocarbons and carbon monoxide from automobile tailpipes, and the best solution was the catalytic converter which works with finely divided platinum particles deposited on alumina monoliths. When leaded gasoline is used, these platinum atoms would be quickly covered by a barrage of lead aerosols. This finally led to the abolishment of TEL as a gasoline additive. 

Unfortunately for Houdry, the lead in gasoline used at the time fouled the catalyst. After operating for a short period, the catalyst lost its ability to filter out noxious gases. Houdry s company failed. Two decades later, however, after lead had been banned in gasoline, his idea was reinvented and became the basis of nearly all modern catalytic converters. 

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