Determination of methylamine, dimethylamine, and trimethylamine in air by high-performance liquid chromatography with derivatization using 9-fluorenylmethylchloroformate

An HPLC-UV method coupled with 9-fluorenylmethylchloroformate (FMOC) derivatization was developed for the determination of short chained amines in an environmental matrix. The basic reaction conditions among different target compounds (three methylated amines: mono- (MA), di- (DMA), and trimethylamine (TMA)) with the reagent (FMOC) have been investigated. Comparative calibration of TMA as an individual target and in a mixture (i.e., with MA and DMA) indicated enhanced sensitivity of the former (response factor (RF) of 7593) and a suppressed pattern for the latter (RF = 3732). According to the kinetics studies, a minimum of 40 min was required for their derivatization. The detection limits of MA, DMA, and TMA derived using liquid standards were 0.12, 0.08, and 0.05 ng, respectively. To validate the applicability of this method, an environmental sample was analyzed by derivatizing amines released from rotten fish. For this purpose, a simple impinger method based on dynamic headspace sampling was developed to collect the amine gas. For derivatization, the gas sample was passed through a train of three impingers (with FMOC in acetonitrile solution). The analysis of the real sample made using a rotten fish (thornback ray: Raja clavata) yielded significantly high concentrations of MA (61 ppm) and TMA (190 ppm) with their overall capture and derivatization efficiencies of 93 and 98%, respectively. Its spoilage level, evaluated in terms of the total volatile basic nitrogen (TVBN), corresponded to 38.2 mg N per 100 g of fish, confirming biodegradation of fish as the potent source of amine.