Determination of nitrosamines by liquid chromatography with post-column photolysis and electrochemical detection

The liquid chromatographic detection of nitrosamines at the ppb (10(9)) and sub-ppb levels is still a difficult problem. A significant improvement was achieved when a nitrosamine eluted from the column was photolysed by a UV lamp, the charged nitrite species being detected amperometrically. N-Nitrosodimethylamine (NDMA) was selected as a model solute to test the applicability of the detection device. The calibration graphs were linear over a wide concentration range. Optimal detection depended on the nature of the buffer used and the UV spectrum of the nitrosamine to be detected. An interesting application of the detection of a high-molecular-weight nitrosamine is given as an example.