Analysis of Two Kinds of Tetrodotoxins in Puffer Fish and Nassarius by Ultra High Performance Liquid Chromatography – Tandem Mass Spectrometry with Direct Dilution Approach

Summary

An ultra high performance liquid chromatography – tandem mass spectrometric (UPLC – MS/MS) method was established for the determination of two tetrodotoxins (TTXs) , eg TTX and 4, 9-anhTTX, in puffer fish and nassarius with a direct dilution technique. Samples were extracted with acetic acid – methanol (1 : 99, by volume). After centrifuged and diluted by 80% methanol solution, the extract was separated on an ACQUITY BEH Amide (100 mm ×2. 1 mm, 1. 7 µm) column by gradient elution, with 0. 1% formic acid solution containing 0. 5 mmol/L ammonium formate – 0. 1% formic acid acetonitrile solution as mobile phases, analyzed in ESI mode under multiple reaction monitoring(MRM) mode and quantified by external standard method. There were good linear relationships in the range of 0. 5 – 100 μg/L for TTX and 0. 5 – 50 μg/L for 4, 9-anhTTX, with their correlation coefficients (r²) larger than 0. 99. The limits of detection (LOD) and limits of quantitation (LOQ) were in the ranges of 100 − 150 μg/kg and 300 − 450 μg/kg, respectively. Recoveries at three spiked levels ranged from 75.4% to 96. 8% , with intra-day relative standard deviations (RSD) and inter-day RSD of 2. 3% − 9. 5% and 5. 3% − 9. 2% , respectively. The method was simple and high sensitive, and was suitable for the determination of two TTXs in puffer fish and nassarius.