Zone refining provides a convenient and effective method for purifying nitrogen compounds for spectroscopic standards. These standards are required by American Petroleum Institute Research Project 52 in its study of the nitrogen constituents of petroleum (2). Two programs have been set up. A standard sample program to prepare 1 to 2 liters of compounds having purities of 99.9. mole percent; and a small sample program to purify available quantities to as high purities as are practical. The first program is designed to furnish samples for determining spectroscopic patterns of highest quality as well as physical and thermodynamic properties, and to provide calibration standards for quantitative work. The second program is designed to furnish samples so that a large catalog of spectral patterns can be obtained rapidly.