Freshness evaluation of grass carp by volatile biogenic amines monitored by secondary electrospray ionization ion mobility spectrometry

In this paper, a secondary electrospray ionization ion mobility spectrometry (SESI-IMS) method using ammonium acerate was evaluated for rapid determination of the various volatile biogenic amine contents in grass carp (Ctenopharyngodon idella). The ammonium ion generated by electrospray ionization source functions as reactant ion to react with volatile biogenic amines in gas phase and separated in the drift tube. The SESI-IMS method requires minimum sample preparation and minimum interferences, and volatile biogenic amines show their unique drift times without overlapping. The content of volatile biogenic amines demonstrates good correlations with storage times at 4 degrees C and 8 degrees C cold storage. It is shown that trimethylamine and putrescine are the dominant biogenic amines during the cold storage process. Other freshness indicates including sensory evaluation, hardness, pH and total volatile basic nitrogen (TVB-N) also show good consistency with volatile biogenic amines. The developed method is a rapid, simple, and sensitive method for the determination of volatile biogenic amines in grass carp.