DETERMINATION OF TRIMETHYLAMINE OXIDE IN SEAWATER AND SMALL VOLUMES OF SEAFOOD TISSUE-EXTRACT USING FLOW-INJECTION ANALYSIS

A method is described for the indirect determination of trimethylamine oxide (TMAO) in small volumes of seawater (300 mu l) and in seafood t issue extracts (100 mu l). After simple TMAO reduction to trimethylami ne (TMA), the samples were directly injected into the flow injection s ystem enabling the TMAO to be measured as TMA. Calibration of the meth od with acidic TMAO standard solutions in the range of 10-200 mu mol l (-1) (n=10) and with seawater TMAO standard solutions in the range of 10-100 mu mol l(-1) (n=8) gave linear calibration curves (r=0.999 in e ach case). The minimum detectable level for the method was 6 mu mol l( -1) while using the acidic standard solutions and 2.5 mu mol l(-1) for seawater TMAO standard solutions. Relative standard deviations were f ound to be <2% in all instances.