ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Determination of the carboxyl groups of pectin by the precipitation of insoluble copper pectates and pectinates

R. Kohn and V. Tibenský

Slovak Academy of Sciences, Bratislava

Abstract: The conditions for the detn. of free and total COOH groups of pectin by pptn. of insol. Cu pectates and pectinates (Tibensky, et al., CA 59, 11795b) were described. Pectins of various origin with the degree of esterification in the range 0-80% were tested. For the detn. of free carboxyl, pH must be adjusted to 7.0 by addn. of NaOH. For the detn. of total carboxyl after hydrolysis of esters, the pH must be adjusted to 5.3-5.5 by addn. of AcOH. HCO₃^--must be absent. When the concn. of free carboxy is 2 × 10_-2 -2 × 10^-3 equiv./1., the deviation is ±1.3%; When concn. of total carboxyl is 1 × 10^-2 equiv./l., the deviation is±1.0% (both relative to the acidimetric method).

Full paper in Portable Document Format: 192a98.pdf (in Slovak)

Chemical Papers 19 (2) 98–106 (1965)