Determination of volatile basic nitrogen and trimethylamine nitrogen in fish sauce by flow injection analysis

A combination of flow injection analysis (FIA), gas diffusion cell and a laboratory built photometer were introduced and used for monitoring trimethylamine (TMA) and total volatile bases (TVB) in fish sauce. The FIA results were compared with commonly used methods. (Dyer method for TMA, Antonacopoulos and Vynke (steam distillation) for TVB). The results for TVB-N were the same by FIA and commonly used methods. However, the results for TMA-N showed significant differences between different methods. The values given by FIA were approximately half those obtained by the method. FIA appears to be an adequate methodology for quality control in fish sauce production with the advantages of reduced sample volume, energy consumption and cost.