V O L U M E 2 7 , NO. 1, J A N U A R Y 1 9 5 5 sulluric acid is green throughout the entire range of concentrations tested (from 2 to 500 y ) ; the color varies only in intensity. The smallest amount of m-terphenyl detectable is 2 y; the color is violet regardless of concentration and varies only in intensity. The lowest amount of p-terphenyl which is detectable in cyclohexane solution is 2 y; the color is magenta regardless of concentration. Interferences. Interferences between biphenyl and p-terphenyl are shown in Table VI. Three factors have an effect on the color reaction: the ratio of biphenyl to p-terphenyl (per cent by weight of biphenyl), the total quantity of biphenyl, and the total volume of the solution. When the total solvent volume is approximately 0.5 ml., 9 to 17% biphenyl (5 to 10 y of biphenyl per 50 y of p-terphenyl) can be detected. On the other hand, should the quantity of biphenyl exceed 10 y (as in 20 y per 100 y of p-terphenyl), then the p-tcrphenyl color would lmonie obscured by the more intense biDheny1 color. When the total solvent volume is 1 to 2 ml., 13 to 33% biphenyl (15 to 50 y of biphenyl per 100 y of p-terphenyl) can be detected. When the biphenyl concentration reaches 37% or more its color masks that of p-terphenyl regardless of dilution, so that small amounts of p-terphenyl could not be detected in greater amounts of biphenyl. Interferences between biphenyl and nt-terphenyl are s h o m in Table VII. The total quantity of biphenyl and the total volume of solvent are not so critical as in the detection of biphenyl in p-terphenyl. When the volume of solvent is approximately 0.5 ml., 9 to 37% biphenyl (10 to 60 y of biphenyl per 100 y of m-terphenyl) can be detected. When the total solvent volume is 1 ml. or more, 17 to 50% biphenyl (20 to 100 y of biphenyl per 100 y of m-terphenyl) can be detected. Above 60% the biphenyl color masks that of the m-terphenyl.
99 The work was not extended to mixtures of biphenyl and o-terphenyl. CONCLUSION
The value of this test lies in the fact that it may be used in conjunction with ultraviolet spectroscopy to follow the separation of polyphenyls by chromatographic or by other means. When two parallel chromatographic separations are made on paper, one of the strips can be analyzed wit,h the formaldehyde-sulfuric acid reagent after extraction into cyclohexane. Such analyses offer quick location of the separated materials by the R/ value nnd give clues to their nature. Ultraviolet analysis of the cyclohexane extracts of the other parallel strip serve to identify thc separated components further and provide a quantitative analyriv of the original sample. LITERATC!RE CITED (1) Fickleti, J. l3.. “Manual of Industrial Health Hazards,” p . 43. Lancaster, Pa., Science Press Printing Co., 1940. (2) Jacobs, >I. B., “Analytical Chemistry of Industrial Poisons. Hazards and Solvents,” pp. 521-55, Interscience Publishers. Kew York, 1941. (3) Le Rosen, R. L., hloravek, R. T., and Carltoii, J. I
