Determination of stability constants of copper (II)-fulvate complexes

Date

1-1992

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Aloysius U Baes

Abstract

Stability constants (K) for the formation of Cu(II)- fulvates were determined using charge transfer absorption spectrometry combined with ion-selective electrode measurements. A reference fulvic acid extracted from a Spodosol (Typic Cryorthod) from Alaska was used for this study. Different concentrations of Cu(II)-fulvates were prepared at three pH levels (4.0, 5.0, and 6.0) while maintaining a fixed ratio [FA]/[Cu(11)] of 1.35. The UV difference spectra of the representative sets, one set for each pH levels, showed the same spectra with peaks at 240 nm and 300 nm. The observed peak at 240 nm was assigned to Cu(II)-dicarboxylate complexes and that at 300 nm to Cu(II)-phenolate complexes based on the peaks observed for Cu(II)-phthalate and Cu(II)-salicylate complexes. Absorbances at 240 nm and 300 nm vs Cu(II)-fulvate complex concentration follow the Beer-Lambert's law. Values for the stability constants of Cu(11),-fulvate complexes ranged from 2.05 x 10 to 9.55 x 10'. These results compared well with the results obtained from other techniques used in determining K.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 1992 C4 M35

Document Type

Thesis

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