Determination of tetrodotoxin in seafood using graphitized carbon black clean-up with hilic ultra performance liquid chromatography-triple quadrupole mass spectrometry

Abstract

To develop a rapid hilic ultra performance liquid chromatography (UPLC)-mass spectrum (MS)/MS method for determination of tetrodotoxin in seafood. The sample of muscle and liver of puffer fish and nassarius were extracted with aqueous solution containing 0.2% (V/V) acetic acid (the extract of liver must be purified through HLB cartridge), and then cleanup of extract was accomplished by solid-phase extraction with a graphitized carbon black cartridge. The analysis of tetrodotoxin was carried out on a chromatographic column (Acquity UPLC BEH Amide, 100 mm×2.1 mm×1.7 µm) with gradient elution of 95% (V/V) acetonitrile-H2O both containing 0.1% (V/V) formic acid and 2.0 mmol/L ammonium formate, and detected by positive electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (MRM) mode, and quantified by matrix-match standard solution. The calibration curves were linear in the range of 30 - 10 000, 50 - 10 000 and 30 - 10 000 µg/kg of tetradotoxin in muscle and liver of puffer fish and in muscle of nassarius, respectively. The correlation coefficients were within 0.9963 - 0.9990. The limits of detection were 10, 20 and 10 µg/kg, and that of quantitation were 30, 50 and 30 µg/kg for muscle and liver of puffer fish and muscle of nassarius, respectively. The average recoveries were 81.5% - 93.1%, 82.3% - 106.0% and 83.5% - 95.2% for tetrodotoxin spiked in muscle and liver of puffer fish and in muscle of nassarius, respectively, with relative standard deviation (RSD) of 2.3% - 11%, 4.3% - 14.0% and 3.5% - 13.0% (n = 6). The method was simple, accurate and sensitive, and could be successfully applied to the measurement of tetrodotoxin in puffer fish and nassarius.