Determination of dimethylamine in biological samples by high-performance liquid chromatography

A reversed-phase HPLC method for the quantification of dimethylamine in serum and urine is presented. Dimethylamine (DMA) is converted into a stable fluorescent product by precolumn derivatization with fluorenylmethylchloroformate. The DMA derivative is resolved from derivatives of other amines and amino acids by gradient elution with a total run-time of 15 min. The lower limit of determination in biological samples is 0.1 micromol/l. Recoveries from spiked serum samples were 99-107%. Within- and between-run precision were better than 6%. Concentrations of DMA in serum from normal human subjects (n=8) and from continuous ambulatory peritoneal dialysis patients (n=15) were 3.3+/-1.5 and 29.1+/-12.1 micromol/l, respectively.