The Determination of Glycollic Acid in Sea Water

Abstract

Glycollic acid is probably a major component of the extracellular organic fraction liberated during phytoplankton photosynthesis and presumably plays an important part in energy transfers in aquatic environments (Fogg, 1966). It has been difficult to investigate these possibilities, however, because of the lack of a reliable and convenient method for the determination of glycollate in natural waters. With fresh water, ionexchange resins have been used for separating and concentrating glycollate which may then be estimated colorimetrically using Calkins's method (Fogg, Eagle & Kinson, 1969). This method is time consuming and is much more difficult and laborious with sea water because of the presence of high concentrations of inorganic ions. Koyama & Thompson (1964) determined various organic acids after extraction from sea water with organic solvents but this method is also laborious and for glycollic acid yields ambiguous results. Andrews & Williams (1971) measured free amino acids and also glucose occurring in sea water in μtgl⁻¹ concentrations by retaining them on a copper chelating resin and a charcoal column respectively and eluting them with ammonium hydroxide or 10% ethanol as appropriate.