Direct Rapid Analysis of Tetrodotoxin Contained in Fugu Using DPiMS™-8060

Significance of the Topic

Fugu (pufferfish) is valued as a delicacy but poses a serious food safety risk due to tetrodotoxin (TTX), a potent neurotoxin present in various tissues. Rapid and simple detection of TTX is crucial for quality control in food production, regulatory inspections, and consumer protection, reducing the incidence of accidental poisoning.

Objectives and Study Overview

This study introduces a direct analysis method for TTX in fugu tissues using the Shimadzu DPiMS-8060 probe electrospray ionization tandem mass spectrometer. The aim was to develop a rapid approach that requires no sample pretreatment and delivers high sensitivity and selectivity for TTX detection in liver, ovaries, skin, and muscle.

Methodology

TTX standard solutions (1–300 ng/mL) were prepared in 50 % ethanol. Ten microliters of each solution were placed on a dedicated liquid sample plate and subjected to product ion scanning to optimize the characteristic fragment ion at m/z 162.1. Multiple reaction monitoring (MRM) was carried out using the transition m/z 320.2 → 162.1 with a collision energy of –30 V. Calibration curves were constructed, and detection and quantitation limits were determined.

For real samples, approximately 3 mm tissue pieces from muscle, skin, liver, and ovary of Takifugu poecilonotus were placed on a biological sample plate. A 50 % ethanol droplet (35 μL) was applied to facilitate ionization, and product ion scans were performed under the same MRM conditions.

Instrumentation Used

• Shimadzu DPiMS-8060 tandem mass spectrometer
• Probe electrospray ionization (PESI) source with 700 nm tip
• Dedicated liquid and biological sample plates
• MRM acquisition over a 0.5 min analysis time

Main Results and Discussion

Product ion scanning confirmed TTX fragmentation to m/z 162.1. The calibration curve showed excellent linearity (R2 = 0.997). The limit of detection was 0.47 ng/mL and the quantitative limit was 1.57 ng/mL. In tissue analyses, TTX was detected in all organs, with varying signal intensities reflecting tissue-specific toxin levels. Direct analysis without pretreatment proved effective across all sample types.

Benefits and Practical Applications

The PESI-MS/MS approach on the DPiMS-8060 eliminates lengthy sample preparation and chromatographic separation, delivering results in under one minute. This method is well suited for high-throughput screening in food safety laboratories, regulatory agencies, and point-of-use testing environments.

Future Trends and Applications

Emerging directions include integrating PESI-MS into portable mass spectrometry systems for on-site toxin screening, expanding the method to other marine and plant toxins, and automating sample handling for large-scale food safety monitoring. Coupling with imaging techniques may also enable spatial mapping of toxin distribution in tissues.

Conclusion

The Shimadzu DPiMS-8060 with PESI offers a fast, sensitive, and straightforward solution for direct TTX detection in fugu tissues without sample pretreatment. Its performance supports enhanced food safety inspections and potential consumer-level screening to prevent tetrodotoxin poisoning.

Reference

T. Murata, Direct Rapid Analysis of Tetrodotoxin Contained in Fugu Using DPiMS-8060, Shimadzu Application Note LAAN-A-TM-E072, July 2019.