LC–MS analysis of antifouling agent Irgarol 1051 and its decyclopropylated degradation product in seawater from marinas in Hong Kong

A method for the trace analysis of antifouling agent Irgarol 1051 and its decyclopropylated degradation product in seawater was developed by using reversed-phase LC–MS with quadrupole time-of-flight mass spectrometry detection. Atrazine-d5 was used as the internal standard for the LC–MS determination. Irgarol 1051 and the major degradation product were detected at trace levels in seawater samples collected from several marinas in Hong Kong. The water samples were pre-concentrated by solid-phase extraction with a polystyrene-divinylbenzene cartridge. Quadrupole time-of-flight tandem mass spectrometry in positive ion electrospray ionization was used for the identification and quantitation. The recoveries of Irgarol 1051 and degradation product were >85%. Method detection limits were 0.2 ng l−1 and 0.8 ng l−1 for the antifouling agent and the decyclopropylated degradation product, respectively.