Abstract:The aim of the present study was to investigate the pectenotoxin (PTX）profiles in seawater. Solid phase adsorption toxin tracking (SPATT) methods were adopted to adsorb toxins in seawater. The toxins absorption disks (TADs）containing the absorbent were hung at 3m depth in seawater at the sampling locations (36°12.428′N, 120°17.826′E) in Jiaozhou Bay of Yellow Sea from Jul. 28 to Aug. 29, 2006. After 4 days, the disks were taken out and a new disk was hung. The toxins in the resin were washed out with methanol. The methanol fraction was evaporated to dryness, then re-dissolved in 1.0 ml 80% methanol. The 80% methanol solution was analyzed on the LC-MS/MS system. The MS/MS system was equipped with an electrospray ion source (ESI) operating in positive ionization mode. Injection aliquots were separated on a Waters XTerra C18 column (50 × 2.1 mm, 3.5μm) connected to a C18 pre-column (10 × 2.1 mm, 3.5μm). The mobile phases consisted of 2mmol/L ammonium formate and 50mmol/L formic acid in 95% acetonitrile (mobile phase A) and 2mmol/L ammonium formate and 50mmol/L formic acid in water (mobile phase B). A gradient was run at 0.4ml/min from 35% A to 100% A for 11 min, followed by an isocratic period for 5.5 min at 100% A. The gradient was returned to 35% A over 0.5 min and left to equilibrate at 35% A for 3 min before the next injection.Chromatograms of PTX-2, PTX-2 SA, 7-epi-PTX-2 SA, PTX-11, PTX-12a and PTX-12b of extracts of seawater were given respectively. PTX-2, PTX-2 SA and 7-epi-PTX-2 SA were found in seawater of this area. The highest levels of PTXs (PTX-2, PTX-2 SA,and 7-epi-PTX-2 SA) in seawater were found on Aug. 1st, 2006. From Aug. 1st to Aug. 29th, the levels of PTX-2 and PTX-2 SA decreased. PTX-11, PTX-12a, and PTX-12b were not found in seawater of Jiaozhou Bay， Yellow Sea.
