TRIMETHYLAMINE-SPECIFIC ELECTRODE FOR FISH QUALITY-CONTROL

Trimethylamine (TMA) is one of the major components of the smell of spoiled marine fish. An increased TMA level is so characteristic of spoilage that the TMA levels have been used as an objective index of fish quality. A specific electrode was developed in order to simplify the measurement of TMA. The Orion ammonia electrode was made specific for TMA by replacing the inner filling solution with 0.01M TMA .cntdot. HCl in 0.04M KCl and by adding enough formaldehyde to the sample solution to obtain a concentration of 0.22% (0.075M). The electrode is suitable for the measurement of TMA in aqueous solutions and in homogenates of fish muscle. The use of this electrode is much simpler than the methods now used for TMA analysis and it may be applicable in commercial practice.