A handbook of sugar analysis : a practical and descriptive treatise for use in research, technical and control laboratories / C.A. Browne.

  • Charles Albert Browne
Date:
1912
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Licence: In copyright

Credit: A handbook of sugar analysis : a practical and descriptive treatise for use in research, technical and control laboratories / C.A. Browne. Source: Wellcome Collection.

    47/986 (page 31)
    Knowing the value of 7, the specific gravity dt at temperature t can be calculated from the specific gravity dt0 at temperature t0 by the equation dt = dto -f- dto X y (to — t). In the employment of temperature corrections in densimetric methods of analysis, it is more customary to apply the correction to the percentage of sugar (degrees Brix) rather than to the specific gravity. The correction is to be added in case the temperature is above, and to be subtracted in case the temperature is below, the standard degree of the table (17.5° C. for the old Brix tables and 20° C. for the new tables of the German Commission). Lists of such corrections are affixed to the standard tables of specific gravities.* Determination of Dissolved Solids by Use of Solution Factors. — In the investigation of starch-conversion products the percentage of solids in 100 c.c. of solution is frequently calculated from the specific gravity by means of a solution factor.” This method was introduced in 1876 by O’Sullivan, f who found that, when 10 gms. of maltose or dextrin were dissolved at 60° F. (15.5° C.) to 100 c.c., a solution of 1.0385 sp. gr. (jffs) was obtained. Assuming that the percentage of dissolved substance is always proportional to the specific gravity of the solution (which is only approximately true), a solution containing 1 gm. of maltose or dextrin in 100 c.c. should have a specific gravity of 1.00385 at 15.5° C. A solution of specific gravity d should contain at 15.5° C -1-000) 3.85 gms. of solids. Brown, Morris, and Millar J determined the solution factors of a number of different sugars for a uniform specific gravity of 1.055—1 with the following results: 15-5° Table VI Solution Factors of Sugars and Starch Conversions Anhydrous glucose Anhydrous sucrose Anhydrous invert sugar Anhydrous fructose Anhydrous maltose Low starch conversion ([a]^ = +149.7) Medium starch conversion ([aj^ =+173.9) High starch conversion ([a]^ = +188.6) Dextrin 3.825 3.859 3.866 3.907 3.916 3.947 3.985 4.000 4.206 * Appendix, Tnb.es 2 and 4. f J. Chen,. Soe. (1876), 129. I J. Chem. Soc. (1897), 71, 72.