Analysis of carbohydrates and amino acids in vegetable waste waters by ion chromatography

High-performance anion exchange chromatography coupled with pulsed amperometric detection was used for the quantitative determination of total and free sugars in olive oil mill waste waters (OMWW). Automated amino acid ion chromatography was employed to analyse total and free amino acids in the same OMWW. Sugars were analysed in samples pre-purified by means of a three-step purification procedure involving: (i) methanol precipitation of OMWW; (ii) dialysis of the obtained solid and liquid fractions; and (iii) chromatographic purification on RP18 phase followed by Amberlite resin. The amino acids were determined directly in samples obtained from the first two steps performed for sugar analysis. The analysis carried out with the reported methodologies allowed the quantitative determination of total sugars and amino acids and the differentiation between their free and bound forms. The sugars determined were arabinose, fructose, galactose, glucose, rhamnose, xylose, galacturonic and glucuronic acids, and the amino acids were Asp, Glu, Thr, Ser, Pro, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe, Lys, His, Arg and Cys. Asn, Gin, and Trp were not detected. The technological, biotechnological and environmental advantages arising from this analytical methodology applied to OMWW are briefly discussed.