Quantitative Determination of Tetramethylammonium in Blood and Urine Samples by Liquid Chromatography-Tandem Mass Spectrometry

Tetramethylammonium (tetramine), a highly toxic compound, is found in high levels in the salivary glands of the sea snail, Neptunea. Tetramine neurotoxicity is fatal, and therefore, prompt determination of tetramine in patients’ biological samples is important in guiding proper and timely treatment. However, there are only a few reports on the quantitative determination of tetramine in human’s biological samples. In the present study, we developed a liquid chromatographytandem mass spectrometry (LC-MS/MS) method with simple protein precipitation for sample extraction. Using the method, we performed a quantitative determination of tetramine in blood and urine samples of a couple who were transferred to a hospital emergency room mentioned after consuming Neptunea. The validation parameters including linearity, accuracy, precision, matrix effect, and recovery were satisfactory. The concentrations of tetramine in the husband’s femoral vein blood and urine were 1.37 mg/L and 15.07 mg/L, respectively, and 0.57 mg/L and 5.85 mg/L, in the wife’s blood and urine, respectively. Since few studies have reported toxic and fatal levels of tetramine in blood, this study can be a reference to evaluate tetramine poisoning in the clinical and postmortem toxicology.