Determination of Tetrodotoxin in Shellfish from Eastern Fujian by Using the Dispersive Solid Phase Extraction Combined with UPLC-MS/MS

In this paper, a confirmation method for the determination of tetrodotoxin content in shellfish in eastern Fujian by using the dispersive solid phase extraction combined with UPLC-MS/MS was established. The pretreatment for the samples was carried out and the chromatographic conditions were optimized. The homogeneous samples of shellfish were extracted with 90% methanol and 0.5% acetic acid solution. After the centrifugation, the supernuant was quickly purified with the mixed powder of graphitized carbon black (GCB) and C18. Then, the supernatant was filtered through the nylon membrane and separated by using the Waters AQUITY UPLC BEH HILIC chromatographic column. The acetonitrile-0.1% formic acid solution was used as the mobile phase for the gradient elution. And the UPLC-MS/MS analysis was performed and quantified by using the matrix-matched standard curve of external standard method. The results showed that under the optimized experimental conditions, the separation and analysis of chromatography of tetrodotoxin from shellfish were completed within 5.4 min. The linear relationship was good in the range of 0.5-100 ng·mL^-1, with the correlation coefficient (r²)=0.995. The limit of detection (LOD) of the method was 5 μg·kg^-1, and the lower limit of quantitation (LOQ) was 15 μg·kg^-1. At three different spiked levels of 15, 30, 150 μg·kg^-1, the recoveries of tetrodotoxin in shellfish were 89.4%-99.0%, and the relative standard deviations (RSD, n=6) were 7.2%-15.2%. The method was accurate, simple and fast, with low pretreatment cost and strong practicability, which could meet the technical requirements of the rapid quantitative detection of tetrodotoxin content in shellfish.