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.