THE LEAD VALUE OF MAPLE PRODUCTS
Journal of the American Chemical Society
The addition of lead subacetate or lead acetate to maple products in solution and a determination of the resulting precipitate constitutes one of the most important and most frequently used tests for purity of these products. Lead acetate when added to a pure maple product precipitates the malic and other organic acids, as well as chlorides, sulphates and carbonates, coloring and other organic matters. In cane sugar solutions this precipitation does not take place, and in maple products
... ted with cane sugar the precipitate decreases as the cane sugar increases. The lead acetate precipitation methods may be divided into four classes: first, those in which the bulk or volume of precipitate is determined-Jones,l Hortvet,2 Sy second, where the weight of the total precipitate is determined;' third, where the amount of acid radicals combined with the lead in the precipitate is determined, Hill and Mosher;5 fourth, in which the amount of lead in the precipitate is determined, Winton," and the method to be described in the following. The Lead b'alue of M a p l e Pvoducts.-Since the preliminary note? on this method, sufficient data have accumulated and satisfactory results obtained on inspection samples of maple products, so that it is thought of interest to analysts to give the method in detail. By "lead value" is meant the amount of lead precipitated by adding a solution of lead acetate to IOO grams of sugar or IOO cc. of sirup. The preliminary results with this method were obtained by the following procedure: to j o grams of sugar or j o cc. of sirup about 2 0 0 cc. of water were added, the solution heated to boiling, excess of a saturated solution of lead acetate added, allowed to settle and filtered. The lead was then determined in the precipitate by the usual method, as lead sulphate, 17th Annual RPt. Vermont Ex$. Sta., p. 454.