Quantification of TMA in fishery products by direct sample analysis with high resolution mass spectrometry

Seafood freshness is a quality key parameter due to the short shelf life of this highly perishable foodstuff in relation to safety, nutritional value, availability, and edibility. A variety of physical, microbiological, and chemical methods are used for assessing and predicting seafood quality. Chemical analyses to assess seafood freshness quality are based on the determination of substances like volatile amines that are structurally similar to ammonia and responsible for the fishy odour fish give off several days after catch. Here we report the results of a method to detect and quantify trimethylamine (TMA) by means of direct sampling analysis (DSA) coupled with a high-resolution mass spectrometer with a time of flight detector (TOF). Three different seafood products, Sea bream (Sparus aurata), Octopus (Octopus vulgaris), and Red mullet (Mullus barbartus) purchased fresh from a wholesale fish market (Savona, Ligurian Sea, Italy) were analyzed. The TMA adduct was correctly identified in all samples. Monitoring of TMA levels in the wholesale products from day 0 to day 20 showed an increase in all samples, confirming deterioration of freshness quality. This innovative, simple, and rapid method may prove useful for routine screening analysis and holds promise as a tool to evaluate seafood freshness quality and protect consumers from potential health risks.