Buffered solutions, carbohydrate oxidation

Bromine water, III, 133, 140, 150 p-Bromophenylhydrazine, in identification of uronic acids, I, 339 Brucella melitensis, antigens, II, 166, 200 Brucellosis, III, 339 Brucine D-altronate, I, 73 Brucine L-altronate, I, 73 Brucine salts, III, 143, 144, 164 —, with uronic acids, I, 339 Buffered solutions, carbohydrate oxidation in, III, 151... 

Although the Tollens reaction is a useful test for reducing sugars, it doesn t give good yields of aldonic acid products because the alkaline conditions cause decomposition of the carbohydrate. For preparative purposes, a buffered solution of aqueous Br2 is a better oxidant. The reaction is specific for aldoses ketoses are not oxidized by aqueous Br2. 

Certain solubility factors are to be considered in work with periodate at different pH values. Above pH 5, disodium paraperiodate (Na2HJ06) tends to crystallize from aqueous solutions.246 Below pH 5, the sodium salt of periodic acid is more soluble, whereas above pH 5, the potassium salt is best employed. Phosphate-buffer solutions cause erroneous results,23 69a 60 61 and should be avoided in oxidations of carbohydrates. 

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