[Determination of tetrodotoxin in nassarius by solid-phase extraction, ultrafiltration and liquid chromatography-mass spectrometry].

A method for the determination and analysis of tetrodotoxin (TTX) in nassarius using liquid chromatography-mass spectrometry (LC-MS) has been developed. The homogenized sample was extracted with 0.03 mol/L acetic acid by heating in a boiling water-bath for 10 min and then was cleaned up on a Sep-Pak C18 cartridge column and filtered through a M(r) 3 000 cut-off ultrafree microcentrifuge filter. Chromatographic separation was performed on an Insertsil ODS-3 column using 30 mmol/L heptafluorobutyric acid in 1 mmol/L ammonia formate buffer-methanol (99 : 1, v/v) as mobile phase at a flow rate of 0.3 mL/min. TTX was identified by retention time in positive mode with selected ion monitoring (SIM). The results showed that TTX and its analogs can be separated with the method. The linear range was 0.01 - 10.0 mg/L and the correlation coefficients were greater than 0.995 with a detection limit of 2 microg/L (S/N = 3). The average recoveries were in the range of 72.5% - 80.4% and the relative standard deviations were 4.48% - 8.87%. TTX of 0.04 - 0.50 mg/kg was found in nassarius that was collected from Fujian Province after red tide.