Organic acids in seawater

Quinn, J. G. and Meyers, P. A. (1971). Retention of dissolved organic acids in seawater by various filters. Limnol. Oceanogr, 16, 129-131. 

Yang, X. H., Lee, C., and Scranton, M. I., Determination of nanomolar concentrations of individual dissolved low molecular weight amines and organic acids in seawater. Anal. Chem., 65, 572-576, 1993. 

One of the earliest applications of gas chromatography to marine problems was in the measurement of fatty acids in seawater. In general, the gas chromatographic method has employed extraction into organic solvent, followed by the... 

Simply on the basis of the normal composition of marine organisms, we would expect proteins and peptides to be normal constituents of the dissolved organic carbon in seawater. While free amino acids might be expected as products of enzymic hydrolysis of proteins, the rapid uptake of these compounds by bacteria would lead us to expect that free amino acids would normally constitute a minor part of the dissolved organic pool. This is precisely what we do find the concentration of free amino acids seldom exceeds 150 xg/l in the open ocean. It would be expected that the concentration of combined amino acids would be many times as great. There have been relatively few measurements of proteins and peptides, and most of the measurements were obtained by measuring the free amino acids before and after a hydrolysis step. Representative methods of this type have been described [245-259]. Since these methods are basically free amino acid methods, they will be discussed next in conjunction with those methods. 

Blumer M (1970) Dissolved organic compounds in seawater. Saturated and olefinic hydrocarbons and singly branched fatty acids. In Hood DW (ed) Organic matter in natural waters. Publication no. 1. Institute of Marine Science, University of Alaska, pp 153-167... 

Repeta DJ, Hartman NT, John S, Jones AD, Goericke R (2004) Structure Elucidation and Characterization of Polychlorinated Biphenyl Carboxylic Acids as Major Constituents of Chromophoric Dissolved Organic Matter in Seawater. Environ Sci Tech 38 5373... 

Well-defined organic compounds. Some of the relatively few organic molecules in seawater with a known structure have been examined for their binding ability with trace metals, e.g. amino acids (Simoes Goncalves et al., 1982, 1983 Valenta et al., 1984) and phtalic-, citric- and salycilic acid (Stumm and Brauner, 1975). 

Goncharova and Khomenko [339] have described a column chromatographic method for the determination of acetic, propionic and butyric acids in seawater and thin layer chromatographic methods for determining lactic, aconitic, malonic, oxalic, tartaric, citric and malic acids. The pH of the sample is adjusted to 8-9 with sodium hydroxide solution. It is then evaporated almost to dryness at 50-60°C and the residue washed on a filter paper with water acidified with hydrochloric acid. The pH of the resulting solution is adjusted to 2-3 with hydrochloric acid (1 1), the organic acids are extracted into butanol, then back-extracted into sodium hydroxide solution this solution is concentrated to 0.5-0.7ml, acidified, and the acids separated on a chromatographic column. 

Mills et al. [17] have reported that tetraphenylboron and diphenyboric acid in seawater samples can be preconcentration on Ci8 reverse phase resin. Naturally occurring organic matter in a black water coastal plain stream did not interfere. 

Armstrong and co workers observed that organic matter in seawater could be oxidized to carbon dioxide on exposure to U.V. radiation. This approach has also been used to decompose for o-arsanilic acid and for sodium cacodylate giving recoveries 97 and 108% respectively. 

Figure 8.113 SIM traces for six low-molecular weight organic acids in synthetic seawater from MS Peaks (1) acetate, (2) propionate, (3) formate, (4) butyrate, (S) pyruvate, and (6) valerate.

Structual steel in aqueous environments (e.g., oil-production platforms in the Gulf of Mexico) undergoes corrosive dissolution via a number of chemical reactions. The protective oxide coating [Fc203] is especially susceptible to removal by the acids, salts, and organic matter in seawater, which leaves an exposed iron surface. Two ther-... 

Important applications for titanium have been developed in processes involving acetic acid, malic acid, amines, urea, terephthalic acid, vinyl acetate, and ethylene dichloride. Some of these represent large scale use of the material in the form of pipework, heat exchangers, pumps, valves, and vessels of solid, loose lined, or explosion clad construction. In many of these the requirement for titanium is because of corrosion problems arising from the organic chemicals in the process, the use of seawater or polluted cooling waters, or from complex aggressive catalysts in the reaction. 

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