Trace lead analysis method
AssigneeMobil Oil Corporation
InventorCatherine A. Zelaskowski
Life of this patent
Estimating the term…
Abstract
The lead content of gasolines, particularly in concentrations of from 0.00 to 0.10 gram of lead per U.S. gallon of gasoline, is determined colorimetrically by mixing iodine and tetraorganoammonium halide solution with the gasoline, subjecting the mixture to ultraviolet light or heat, agiating the mixture with ammonium nitrate or nitric acid, passing the aqueous phase into 4-(2-pyridylazo)-resorcinol disodium and comparing the resulting color with a standard color scale or a colorimeter to determine the initial lead concentration.
Claims9
A method for colorimetrically determining the lead content in gasoline comprising (1) mixing a gasoline sample containing tetraalkyllead with iodine in the presence of a tetraorganoammonium halide and exposing the mixture to ultra-violet radiation from a 3660 A wavelength ultra-violet source for a period of from 30 seconds to about 10 minutes sufficient to convert the tetraalkyllead to dialkyllead diiodide, (2) mixing the resulting reaction mixture with an aqueous solution of an acidic compound selected from the group consisting of nitric acid and ammonium nitrate and separating the resulting aqueous phase from the organic gasoline phase, and (3) combining the aqueous phase with an alkali metal salt of 4-(2-pyridylazo)-resorcinol in an aqueous solution to produce a color corresponding to the initial lead concentration.
A method for colorimetrically determining the lead content in gasoline comprising (1) mixing a gasoline sample containing from 0 to over 0.10 grams of a tetraalkyllead compound per gallon of gasoline with iodine in the presence of a tetraorganoammonium halide and exposing the mixture to ultra-violet radiation from a 3660 A wavelength ultra-violet source for a period of from 30 seconds to about 10 minutes sufficient to convert the tetraalkyllead to dialkyllead diiodide, (2) mixing the resulting reaction mixture with an aqueous solution of an acidic compound selected from the group consisting of nitric acid and ammonium nitrate and separating the resulting aqueous phase from the organic gasoline phase, and (3) combining the aqueous phase with an alkali metal salt of 4-(2-pyridylazo)-resorcinol in an aqueous solution to produce a color corresponding to the initial lead concentration.
Dependencies are inferred from the claim text.