Microconcentric nebulizer for the coupling of micro liquid chromatography and capillary zone electrophoresis with inductively coupled plasma mass spectrometry

A concentric nebulizer designed to deliver less than 10 mu l min(-1) directly into an ICP-MS system is described, The influence of the liquid flow rate, the nebulizer gas flow rate and the distance from the nebulizer tip to the plasma was evaluated with regard to sensitivity and precision, The nebulizer was tested at liquid flow rates of 3-7 mu l min(-1). Samples of tetramethyllead and tetraethyllead dissolved in dimethylformamide were used for the evaluation of the nebulizer. The detection limit for Pb (m = 208) with a direct injection system was found to be 0.3 pg (S/N = 3) or 5 mu g l(-1), based on an injection volume of 60 nl, a liquid flow rate of 5 mu l min(-1) and a dwell time of 10 ms. The precision was found to be 1.9% (n = 10) based on peak area measurements, The responses of tetramethyllead and tetraethyllead were not significantly different (p = 0.05), The time needed for one determination was less than 15 s, owing to the quick rinse out of the nebulizer, The nebulizer can be used as part of a direct injection instrumental set-up. An application of the nebulizer to the coupling of packed capillary liquid chromatography with ICP-MS detection is demonstrated.