Sensitive determination of tetrodotoxin using column-switching liquid chromatography-mass spectrometry with electrospray ionization in mouse serum

A liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method coupled with a column-switching technique was developed for the determination of tetrodotoxin (TTX) in serum. An on-column, column-switching technique was employed to analyze TTX without pretreatment of the serum. The combination of a multimode column with reversed phases and cation exchange for TTX provided successful separation and MS determination in the ESI-positive mode. A 100-microL serum sample was injected directly into a precolumn. For TTX monitored at m/z 320.1 in the selective ion monitoring mode, the calibration curve was linear within the range 0.1-100 ng/mL, and the limit of detection was 0.5 ng/mL. Recoveries were around 90% for TTX. The present method allows successful analysis of TTX in serum. In conclusion, this new method is simple, accurate, and useful for the determination of TTX and should be of benefit to both forensic and clinical toxicology.