Molecular and Equivalent Weights of the Organic Matter of a Podzol

Abstract

AbstractThe number‐average molecular weights of the organic matter of the A0 and Bh horiozons of a Podzol, determined by freezing point depression in sulfolane, were 1684 and 669, respectively. From the molecular weights, in conjunction with ultimate and functional group analyses, molecular formulae were calculated. These were C75H33O17N3 (COOH)3(OH)12(CO)2 for the A0 and C21H12(COOH)6(OH)5(CO)2 for the Bh organic matter. The presence of relatively large numbers of functional groups in the Bh molecule offers interesting possibilities for metallo‐organic interactions.The equivalent weights of the same organic matter preparations, measured by discontinuous potentiometric titrations, were 165 for the A0 and 76 for the Bh organic matter. The ratio of molecular to equivalent weight was 10 for the A0 and 9 for the Bh material. These ratios were in both cases equal to the sum of carboxyl plus phenolic hydroxyl groups in the two molecules.