A rapid method for tetrodotoxin (TTX) determination by LC-MS/MS from small volumes of human serum, and confirmation of pufferfish poisoning by TTX monitoring.

A simple and rapid detection method for tetrodotoxin (TTX), a powerful sodium channel blocker, in small volumes of the serum of patients with pufferfish poisoning, was developed using an ultrafiltration spin column. The separation and identification of TTX was performed by liquid chromatography (LC) with a multi-mode ODS column and tandem mass spectrometry. TTX and an internal standard (voglibose) were monitored and quantitated using ion transitions: the respective precursor-to-product ion combinations, m/z 320/162 for TTX and 268/92 in MRM mode. The recoveries of TTX and voglibose were 91.0-110.8% and 104.7-107.4%, respectively, and with high accuracy (intra-run, 4.35-5.29%; inter-run, 2.95-5.79%) and linearity (0.5-200 ng/ml serum: r = 0.9994). The lower limit of quantification was 0.5 ng/ml serum. In patients, maximum serum TTX concentrations were 30.2 ng/ml serum for patient 1 on day 0 and 56.1 ng/ml serum for patient 2 on day 1. These results are important for the treatment of patients and for the identification of poisoning as well as for the determination of the cause of the food poisoning.