The analysis of trimethylamine in body fluids by a direct medium resolution mass spectrometric method

A simple, high throughput method of analysis of trimethylamine in body fluids has been developed to assist with the management of patients with the inherited metabolic disorder, trimethylaminuria. The headspace in sealed vials was analysed using perdeuterated (2H10)trimethylamine hydrochloride as an internal standard. The gas chromatograph inlet system of the mass spectrometer was adapted to suit this method of analysis. Medium resolving power was used to measure the ion ratio of the [M-H]+ ion of trimethylamine and the [M-2H]+ ion of the internal standard. The method is faster and more accurate than gas chromatographic methods. The concentrations of trimethylamine found in normal urine are similar to those reported previously.