Determination of 2,2-bis-p-Chlorophenyl-1,1,1-trichloroethane in Technical DDT. A Microscopical Method

Microscopic Identification of Organic Compounds

“…Axial dispersion with change of sign (Figure 11) is illustrated in the interference figures of dimethylamine picrate (25). The optic axial angle of the a-0 section decreases with increase in wave length of the light, while that of the /3-y section increases, n-Propylamine picrate (Figure 12) represents an excellent example of strong crossed dispersion (24). Here with decrease in wave length from 6234 A,, the optic axial angle rotates around the optic axis, until at 4750 A. a rotation of approximately 80°has occurred.…”

Application of Fusion Methods in Chemical Microscopy

“…It may be used as well on organic compounds to follow purification by recrystallization, etc. Fusion methods can also be used in various ways for the quantitative analysis of mixtures. The properties of a mixture that can be used to determine the percentage composition of a mixture include: rate of crystal growth of the major component (5), refractive index of a binary melt (3), habit of crystals from the melt ondary Feathery Growth Due to Boundary Migration at Boundaries of Primary Spherites. 10 X (7), optical and geometrical properties of mixed crystals (1), and melting point composition diagram.…”

Light Microscopy.

“…Reimers (111) discusses the advantages and limitations of thermal analysis. Fusion methods have received considerable study' by McCrone and his collaborators (58,59,91,93), who have worked out a method of determining , 'in the technical grade of material, and have studied the kinetics of crystal growth from the melt of binary mixtures. A comparison slide technique for comparing the optical properties of a known with an unknown substance is given by Jellev (74).…”