Identification of a new degradation product of the antifouling agent Irgarol 1051 in natural samples

A main degradation product of Irgarol [2-(methylthio)-4-(tert-butylamino)-6 -(cyclopropylamino)-s-triazine], one of the most widely used compounds in a ntifouling paints, was detected at trace levels in seawater and sediment sa mples collected from several marinas on the Mediterranean coast. This degra dation product was identified as 2-methylthio-4-tert-butylamino-s-triazine. The unequivocal identification of this compound in seawater samples was ca rried out by solid-phase extraction (SPE) coupled on-line with liquid chrom atography-atmospheric pressure chemical ionization-mass spectrometry (LC-AP CI-MS). SPE was carried out by passing 150 ml of seawater sample through a cartridge containing a polymeric phase (PLRP-s), with recoveries ranging fr om 92 to 108% (n=5). Using LC-MS detection in positive ion mode, useful str uctural information was obtained by increasing the fragmentor voltage, thus permitting the unequivocal identification of this compound in natural samp les. Method detection limits were in the range of 0.002 to 0.005 mug/l. Ove rall, the combination of on-line SPE and LC-APCI-MS represents an important advance in environmental analysis of herbicide degradation products in sea water, since it demonstrates that trace amounts of new polar metabolites ma y be determined rapidly. This paper reports the LC-MS identification of the main degradation product of Irgarol in seawater and sediment samples. (C) 2001 Elsevier Science B.V. All rights reserved.