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Electrochemical reduction of o ‐nitrophenol as a tool for the rough characterization of organic matter in seawater samples
Author(s) -
Gas̆parović Blaz̆enka,
Ćosović Božena
Publication year - 1995
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140071208
Subject(s) - seawater , chemistry , adsorption , electrochemistry , voltammetry , cyclic voltammetry , analytical chemistry (journal) , inorganic chemistry , electrode , chromatography , organic chemistry , oceanography , geology
Phase sensitive alternating current (AC) voltammetry with o ‐nitrophenol (ONP) as a probe is used as a simple nondestructive method for a rough characterization of organic substances in natural seawater samples. This is based on the measurement of the effects of adsorbed organic substances on the peak height and the potential of the ONP reduction peak. In this work further improvements are presented of the method which is achieved by introducing the measurement of the prepeak of ONP reduction obtained upon scan reversal. The height of the prepeak is extremely sensitive to the type of organic matter adsorbed on the mercury electrode at the pH of natural seawater. The ONP prepeak increases in the presence of adsorbed layers of negatively charged organic substances, such as humic and fulvic acids and proteins. In the presence of adsorbed polysaccharides of dextran type there is no increase of the ONP prepeak height. With increasing concentrations of the polysaccharides a small decrease of the prepeak is observed. The application of the method is demonstrated on different seawater samples from the north Adriatic sea.